Advertisement

Assessment of air quality, health status and lung function of workers from selected poultry management systems in Ogun State, Nigeria

Open AccessPublished:October 18, 2022DOI:https://doi.org/10.1016/j.cegh.2022.101159

      Abstract

      Background/Objectives

      This study assessed the air quality, health status and lung function of workers from intensive poultry production systems in selected areas of Ogun State.

      Methods

      Air samples were monitored monthly between November 2017 and April 2018 from six pens in three selected poultry zones of Ogun State. The air pollutants (CO2, CH4, NO2, NH3, H2S, SO2, PM2.5) and the microclimatic parameters around the poultry pens were determined. Copies of structured questionnaires were administered to assess the impacts of air pollutants on the health status of the poultry workers. Lung function parameters [Forced Expiratory Volume in 1 s (FEV1), Forced Vital Capacity (FVC), FEV1/FVC and Peak Expiratory Flow Rate (PEFR)] were measured to assess the pulmonary health of the poultry workers and the control group.

      Results

      The levels of NH3, PM2.5, CO2 and CH4 were higher than the permissible standards while NO2, H2S and SO2 were below the permissible limits of the World Health Organization. Regression analysis between pollutants and microclimatic parameters showed that relative humidity and windspeed had negative effects on PM2.5, NO2, H2S and SO2. FEV1/FVC measured for poultry workers was 86.84 ± 18.32% with 10.0% having obstructive lung function, while the control group had 98.82 ± 1.52% with 100% normal lung function pattern. The predicted PEFR for poultry workers was significantly lower at 61.12 ± 27.85% with 13.3% having severe airway restrictions, while the predicted PEFR for the control group was significantly higher at 88.41 ± 21.76% with no severe airway narrowing.

      Conclusions

      This study established that air quality around the poultry operations affected the workers’ health.

      Keywords

      1. Introduction

      The Nigerian poultry industry is estimated at ₦80 billion ($600 million) and is comprised of approximately 165 million birds, with a few large commercial players in the sector located in southwestern Nigeria.
      • Sahel
      An Assessment of the Nigerian Poultry Sector.
      The expansion of poultry production as confined feeding animal operations (CAFOs) is increasingly regarded as a source of air pollution with significant environmental and health impacts in and around the facilities.
      • Copeland C.
      Air Quality Issues and Animal Agriculture: A Primer.
      This result mainly from the litter and manure generated from the production, which poses serious air pollution hazards. The poultry environment contains toxic gases, odours, dust and micro-organisms, which are known to directly attenuate the poultry health; and thus affects the birds’ welfare and productivity and the general wellbeing of the workers and those living close to the poultry farms.
      • Olanrewaju H.A.
      • Dozier W.A.
      • Purswell J.L.
      • et al.
      Growth performance and physiological variables for broiler chickens subjected to short-term elevated carbon dioxide concentrations.
      ,
      • Taiwo A.M.
      • Arowolo T.A.
      • Adekunle I.M.
      • Adetunji M.T.
      Evaluating the environmental impacts of poultry farming on stream water quality: a study from Abeokuta, Nigeria.
      The conditions in the poultry houses depend on physical (temperature, relative humidity, luminance, ventilation and dust) and chemical (components of the air such as ammonia, carbon dioxide and oxygen) factors.
      • Kocaman B.
      • Yaganoglu A.V.
      • Yanar M.
      Combination of fan ventilation system and spraying of oil-water mixture on the levels of dust and gases in caged layer facilities in Eastern Turkey.
      ,
      • Liang Y.
      • Xin H.
      • Li H.
      • et al.
      Ammonia Emissions from U.S. Laying Hen Houses in Iowa and Pennsylvania.
      Studies have reported that the main air pollutants emitted from poultry houses are NH3, CH4, N2O, and inhalable and respirable dust (PM10 and PM2.5).
      • Fournel S.
      • Pelletier F.
      • Godbout S.
      • Lagace R.
      • Feddes J.J.R.
      Odour emissions, hedonic tones and ammonia emissions from three cage layer housing systems.
      IPPC
      Integrated Pollution Prevention and Control) Reference Document on Best Available Techniques for Intensive Rearing of Poultry and Pigs.
      • Pereira J.L.S.
      Assessment of ammonia and greenhouse gas emissions from broiler houses in Portugal.
      The concentrations and emissions of dust particles from the livestock activities are generally determined by the characteristics of the adopted housing system.
      • Heber A.J.
      • Lim T.T.
      • Gallien J.Z.
      • et al.
      Secondary particulate matter (PM) is the main component of livestock dust formed as a result of reactions between ammonia and sulphate/nitrate.
      • Robarge W.P.
      • Walkerb J.T.
      • McCulloch R.B.
      • Murray G.
      Atmospheric concentrations of ammonia and ammonium at an agricultural site in the southeast United States.
      ,
      • Baek B.H.
      • Aneja V.P.
      Measurement and analysis of the relationship between ammonia, acid gases, and fine particles in eastern North Carolina.
      Lung function is an assessment of the respiratory health using an investigative tool known as spirometer. The ratio of the Forced Expiratory Volume (1 s) to Forced Vital Capacity determines if there is any restrictive/obstructive impairment of the lung function. Reduction of both the FEV1 (FEV1< 75% predicted for age and height) and FVC (FVC <80.0% predicted for age and height) indicates a restrictive lung impairment.
      • Barreiro T.J.
      • Perillo I.
      An Approach to Interpreting Spirometry.
      • Akanbi O.G.
      • Ismaila O.
      • Olaoniye W.
      • Oriolowo K.T.
      • Odusote A.
      Assessment of post-work peak expiratory flow rate of workers in cement company.
      reported that peak flow readings were higher when workers are well and lower when the airways are constricted.
      • Iversen M.
      • Kirychuk S.
      • Drost H.
      • Jacobson L.
      Human health effects of dust exposure in animal confinement buildings.
      demonstrated that there was significantly higher prevalence of chronic cough, chronic phlegm, chronic bronchitis, and chest tightness in poultry workers than in control workers. Poultry workers are at greater risk, because most of them do not use Personal Protective Equipment (PPE) especially for respiratory and eye protection when working in these enclosed facilities. The use of PPE aimed at preventing workers from the potential impact of various working conditions is inappropriately lacking in most poultry farms in Nigeria.
      • Adebowale O.O.
      • Adeyemo O.
      Assessment of workplace health and safety measures among poultry workers in a southwestern state of Nigeria.
      ,
      Therefore, the extent of the exposure of poultry workers to potential health hazards in the work environment is not fully understood.
      Air pollutants emanating from poultry operations can initiate numerous health problems ranging from respiratory diseases (asthma), shortness of breath, wheezing, fatigue, headaches, nausea, irritation of eyes and the lungs to premature death.
      • Najjar Y.S.
      Gaseous pollutants formation and their harmful effects on health and environment.
      ,
      • Taiwo A.M.
      • Harrison R.M.
      • Shi Z.
      A review of receptor modelling of industrially emitted particulate matter.
      These pollutants also affect the environment in diverse ways through acid rain formation, disruption of rainfall pattern, climate change and global warming, soiling of monuments and artefacts, environmental pollution (water, soil, air), cloud condensation nuclei, and smog.
      • Taiwo A.M.
      • Harrison R.M.
      • Shi Z.
      A review of receptor modelling of industrially emitted particulate matter.
      ,
      • Taiwo A.M.
      Characteristics of particulate matter collected at an urban background site and a roadside site in Birmingham, United Kingdom.
      Presently, there is little information on the concentration of air pollutants within and around poultry houses in Nigeria (koli et al., 2004;
      • Adebowale O.O.
      • Adeyemo O.
      Assessment of workplace health and safety measures among poultry workers in a southwestern state of Nigeria.
      ,
      • Nwagwu C.
      • Ede P.N.
      • Okoli I.C.
      • Chukwuka O.K.
      • Okoli G.C.
      Study on late rainy season aerial pollutant gases concentrations in tropical poultry pen environment in Nigeria.
      • Okiki P.A.
      • Ogbimi A.O.
      • Edafiadhe W.E.
      Effects of air-borne hazards on the physical and psychological health of Nigerian poultry workers.
      • Uyo C.N.
      • Njoku J.D.
      • Iwuji M.C.
      • Ihejirika C.E.
      • Njoku-Tony R.F.
      Assessment of air quality in livestock farms and abattoirs in selected LGAs of Imo State.
      • Nwagwu C.
      • Ede P.N.
      • Okoli I.C.
      • Chukwuka O.K.
      • Okoli G.C.
      Evaluation of aerial pollutant gases concentrations in poultry pen environments during early dry season in the humid tropical zone of Nigeria.
      stated that research on the concentration and emission rates of aerial pollutant gases in tropical livestock buildings is needed to establish the baselines for exposure limits in the context of animal and human welfare in the tropical environments. Furthermore, comprehensive studies on air pollutants, health status and lung function of workers in confined feeding operations poultry houses in Nigeria are rarely reported.
      This study is therefore important to bridge the existing gaps and to protect public health by assessing the air quality, health status and the lung functions of workers from intensive poultry production systems, and to determine the microclimatic effects on air pollutants.

      2. Materials and methods

      2.1 Study area

      The poultry farms were selected from Ogun state, located in the south western region of Nigeria. The state was created in February 1976 and currently has twenty Local Government Areas (LGA) and thirty-seven Local Council Development Areas (LCDAs). It lies on latitudes 6.2 °N to 7.8 °N and longitudes 3.0 °E to 5.0 °E. Ogun state has a land area of about 16,981 km2 with an estimated population of 7.1 million inhabitants.
      • Ogun State Government
      Ogun State Brief.
      NPC (National Population Commission)
      Bulletins on Population Census Figures.
      The state has a tropical climate with rainfall ranging between 900 and 1600 mm annually, and temperature variation between 28 and 35 °C.The map showing the study area is presented in Fig. 1.
      Fig. 1
      Fig. 1Map of Ogun State, Nigeria, showing the sampled pens in the study area.

      2.2 Study design

      The study combines prospective air pollutant assessment, and cross-sectional health status and lung function assessment of poultry workers. Air pollutant assessment was conducted in three poultry farms representatives of small, medium and large sized poultry in Nigeria. Concentrations of NH3, CH4, NO2, H2S, and CO2 and PM2.5were obtained from the direct reading measurements of hand held air quality monitoring equipments. Meteorological parameters such as relative humidity and temperature and wind speed were also measured.
      Descriptive cross-sectional study to evaluate poultry workers’ health and safety practices on poultry was conducted using a questionnaire that contained information on their socio-demographical personal assessment and reported symptoms on the impacts of poultry and their health experiences including a lung function test.
      A control group which constituted individuals that were healthy individuals neither occupationally nor environmentally exposed to poultry were also screened for the lung function test, and administered the questionnaire.

      2.3 Sample collection and analysis

      Three poultry farms in three zones namely: Egba, Remo and Mowe, denoted with letters E, R and M, respectively were purposively selected out of the 6 poultry zones classification of the Poultry Association of Nigeria, Ogun State (PANOG). Two poultry pens were sampled monthly at each poultry house for a period of six months between November 2017 and April 2018.
      Indoor sampling and outdoor sampling were carried out in these poultry houses. Both indoor and outdoor sampling points were identified based on the site survey to get the entire coverage of the surroundings for representative results. The characteristics of the pens (E1, E2 M1, M2, R1 and R2) and the sampled locations outside the pens (E3, M3 and R3) are shown in Table S1 (in the supplementary information).
      The gaseous pollutants [ammonia (NH3), methane (CH4), nitrous oxide (NO2), hydrogen sulphide (H2S), sulphur dioxide (SO2) and carbon dioxide (CO2)] were measured using a hand held air quality monitoring equipment (KanoMax and iTX multigas Analysers) over a period of 1 h at 10 min intervals, while particulate matter (PM2.5) was determined using a Thermo metric sampler (Model PDR 1250). Relative humidity and temperature were obtained from the attached probe on the Kanomax gas analyser, while wind speed was measured with a Multifunctional Microprocessor digital meter Anemometer (Model Am-4836C).

      2.4 Questionnaire administration

      A purposive sampling technique was adopted for respondents’ selection. The targeted respondents were thirty-eight active workers in the three selected poultry farms. This sample size is a typical representation of the population of workers in small, medium and large poultry farms across Nigeria.
      The questionnaire was adapted as a standard from the study of
      • Okiki P.A.
      • Ogbimi A.O.
      • Edafiadhe W.E.
      Effects of air-borne hazards on the physical and psychological health of Nigerian poultry workers.
      ethically approved by the ethical committee of the Faculty of Life Sciences, University of Benin. The targeted respondents were the total population of poultry workers in the three poultry farms who were actively involved with the daily poultry farm activities.
      Participation was offered to all poultry workers who gave their consents. These individuals were asked structured questions to determine the impacts of air pollutants from poultry production on their health. The questionnaire also included the socio-demographic details of the respondents. Questionnaire was self administered to poultry workers, and the control group. In cases where participants were unable to fill the questionnaire due to lack of education and language barrier; they were guided by interpreting the questions and responses were marked as given.

      2.5 Anthropometric characteristics

      The weight was measured using a weighing scale and the heights of workers were measured using a portable stadiometer.

      2.6 Lung function assessment

      Respiratory function parameters (FVC, FEV1, FEV1/FVC% and PEFR) were evaluated using a handheld spirometer (SP10) according to the ATS standard.
      • Miller M.R.
      • Hankinson J.A.T.S.
      • Brusasco V.
      • et al.
      Standardisation of spirometry.
      A demonstrative exercise showing the manoeuvre was explained to each respondent to enable them to do the right thing. They were encouraged to practice this manoeuvre before performing the lung function tests. Each person was examined in a sitting position. A disposable mouthpiece was inserted to the inlet of spirometer for each participant, where air was blown to avoid contamination. The subjects were instructed to inspire deeply and rapidly and then exhaled with a blast and fully into the device. The age, weight, height and gender of the poultry workers and control group were inputted into the device. Three readings were taken and the highest values of FVC, PEFR and FEV during 1 s were recorded and expressed as percent of predicted. A set of prediction equations for the adults using regression analysis was used to calculate the expected values.
      • Reddy U.N.
      • Khan M.A.U.
      • Anjum S.
      • et al.
      Evaluation of mean peak expiratory flow rate (PEFR) of healthy children belonging to urban areas of hyderabad.
      ,
      • Olujimi O.O.
      • Ana G.R.E.E.
      • Ogunseye O.O.
      • Fabunmi V.T.
      Air quality index from charcoal production sites, carboxyheamoglobin and lung function among occupationally exposed charcoal workers in south western Nigeria.
      Lung function conditions are categorised into four types: normal, obstructive, restrictive, and mixed patterns.
      • Pellegrino R.
      • Viegi G.
      • Brusasco V.
      Interpretative strategies for lung function tests.
      Table S2 (in the supplementary information) shows the different spirometry parameters and their interpretation. Subjects with (FEV1/FVC) less than 70% were categorised as having an obstructive pattern of lung function defect.
      • Ibhafidon L.I.
      • Obaseki D.O.
      • Erhabor G.E.
      • Akor A.A.
      • Irabor I.
      • Obioh I.B.
      Respiratory symptoms, lung function and particulate matter pollution in residential indoor environment in ile-ife, Nigeria.
      ,
      • Lopez J.R.
      • Somsamouth K.
      • Mounivong B.
      • et al.
      Environmental exposures, lung function and respiratory health in rural Lao PDR.
      The equations for prediction are presented in Table S3. Lung functions were tested for 30 poultry workers and 30 non-poultry workers (control group).

      2.7 Ethical approval

      Clearance for examination of lung function of the workers was obtained from the Poultry Association of Nigeria, Ogun State (PANOG). The poultry workers who gave their consents were enrolled for the study.

      2.8 Data analysis

      Data obtained from the assessment was subjected to descriptive (Frequency, Percentage, Mean and Standard deviation) and inferential (Analysis of variance ANOVA, Duncan Multiple Range Test DMRT, Student t-test and regression analysis) statistics using SPSS for Windows Version 22.0. ANOVA was used to determine the variations in concentrations of the pollutants levels and means were separated by use of DMRT. Student test was adopted to compare the means of two variables. The multiple regression model (equation (1)) was adopted to determine the quantified relationship between pollutants and microclimatic parameters.
      • Obayelu A.E.
      • Adeniyi A.
      The effect of climate on poultry productivity in ilorin kwara state, Nigeria.
      ,
      • Nwagwu C.
      • Ede P.N.
      • Okoli I.C.
      • Chukwuka O.K.
      • Okoli G.C.
      • Moreki J.C.
      Effect of environmental factors and structural dimensions on aerial pollutant gas concentrations in tropical poultry pen in Nigeria.
      Y = a + x1b1 + + x2b2+ + x3b3 + e ------------------
      Equation 1


      Where, Y = dependent variables (air pollutants), x = independent variables (x1 = relative humidity, x2 = temperature, x3 = wind speed), a = regression constant, b = regression coefficient, e = error term.

      3. Results and discussion

      3.1 Concentrations of gaseous pollutants and particulate matter

      Table 1 shows the air pollutant data obtained at the poultry pens in Ogun state. CO2 ranged from 1273.52 ± 221.71 to 1545.65 ± 279.30 mg/m3 with the highest level at the M1 monitoring site and the lowest amount at M3. CO2 concentrations were significantly higher inside the pens than outdoors. This is because CO2 result mainly from the respiration of birds. The mean concentration obtained from these sites was 1476.04 mg/m3 and was higher than the World Health Organisation (WHO) exposure limit of 100and 10 mg/m3 for 8 h and 15 min, respectively.
      • World Health Organization
      WHO guidelines for indoor air quality: selected pollutants.
      Table 1Mean concentrations of air pollutants in poultry sites.
      Sampled LocationsCO2 (mg/m3)CH4 (mg/m3)NO2 (mg/m3)NH3 (mg/m3H2S ((mg/m3)SO2 (mg/m3)PM2.5 (μg/m3)
      M1 (indoor)1545.65 ± 279.30a0.81 ± 1.37a0.03 ± 0.001b2.73 ± 1.86ab0.04 ± 0.05c0.03 ± 0.78b222.94 ± 228.46c
      M2 (indoor)1466.82 ± 295.91a0.06 ± 0.40b0.03 ± 0.001b2.00 ± 1.5c0.34 ± 0.83b0.33 ± 0.06b222.77 ± 259.26c
      M3 (outdoor)1273.52 ± 221.7bBDL0.03 ± 0.001bBDL0.02 ± 0.02c0.04 ± 0.05b97.90 ± 50.54d
      R1 (indoor)1493.94 ± 206.81aBDL0.03 ± 0.001c2.38 ± 1.36b0.02 ± 0.03c0.01 ± 0.01b434.39 ± 399.05b
      R2 (indoor)1476.04 ± 262.18a0.18 ± 0.45b0.03 ± 0.001b2.20 ± 1.48c0.4 ± 0.88a0.38 ± 0.83a269.92 ± .241.61b
      R3 (outdoor)1303.97 ± 128.82bBDL0.03 ± 0.001b0.23 ± 0.43e0.33 ± 0.67b0.44 ± 0.90a125.61 ± 91.63d
      E1 (indoor)1353.22 ± 225.0bBDL0.03 ± 0.002a1.36 ± 1.12dBDLBDL1469.70 ± 423.44a
      E2 (indoor)1475.17 ± 264.85aBDL0.03 ± 0.001b3.04 ± 1.64a0.02 ± 0.03c0.04 ± 0.9b321.88 ± .278.52b
      E3(outdoor)1353.19 ± 226.03bBDL0.03 ± 0.001b0.25 ± 0.44eBDL0.01 ± 0.03b179.07 ± 212.98d
      Mean1476.040.200.032.220.100.10337.28
      SD262.180.720.0011.670.420.42420.19
      Range1273.52–1545.650.06-0.810.032-0.0340.23-3.040.02-0.40.01-0.4497.90–1469.70
      NESREA (2020)NANA0.04-0.060.30.100.10250
      WHO (2005)9000.060.110.190.0625
      M − Mowe zone, R – Remo zone; E − Egba zone; Means with the similar superscripts along the same column are not significantly different at p > 0.05 according to Duncan Multiple Range Test; BDL- Below Detection limit; NA- Not Available; SD- Standard deviation.
      Methane (CH4) ranged from 0.06 ± 0.40 to 0.81 ± 1.37 mg/m3; and was however, not detected at sites M3, R1, R3, E1, E2 and E3. The highest mean value of CH4 was significantly determined at M1, while the lowest amount was obtained at R2. The battery cage system operated at M1 location allows collection of manure in slurry form in the pit, which provides anaerobic condition resulting in CH4 production, unlike manure in the solid form at E2 site. The mean concentration of CH4 was 0.20 mg/m3, far higher than the 0.06 mg/m3 indoor exposure limit (WHO, 2005).
      Nitrogen dioxide (NO2) varied from 0.032 ± 0.001 and 0.034 ± 0.002 mg/m3. The highest concentration was observed at E1, while the lowest was documented at R1. There was no statistical significance in the concentrations of NO2 at the nine poultry pens. The average NO2 concentration (0.033 ± 0.001 mg/m3) across the locations was lower than the National Environmental Standards and Regulations Enforcement Agency (NESREA)
      NESREA (National Environmental Standards and Regulations Enforcement Agency)
      National environmental (air quality control) regulation.
      and the WHO
      • World Health Organization
      WHO guidelines for indoor air quality: selected pollutants.
      standards of 0.04–0.06 and 0.11 mg/m3, respectively.
      Ammonia (NH3) concentration ranged between 0.23 ± 0.43 and 3.04 ± 1.64 mg/m3. NH3 was below detection limit at M3, while the lowest and highest amounts were observed at sites R3 and E2, respectively. This may be attributed to the manure management practices. Manure is held back at E2, while the wastes from other battery cage pens are disposed within 2–3 days. A similar observation was reported by
      • Heber A.J.
      • Lim T.T.
      • Gallien J.Z.
      • et al.
      ; where the poultry manure was frequently removed.
      Hydrogen sulphide (H2S) concentration ranged from 0.02 ± 0.03 to 0.4 ± 0.88 mg/m3 similar to the findings of.
      • Guarrasi J.
      • Trask C.
      • Kirychuk S.A.
      Systematic review of occupational exposure to hydrogen sulphide in livestock operations.
      The average concentration of H2S at all the sites was within the recommended limit. Sulphur dioxide (SO2) varied from 0.01 ± 0.01 and 0.44 ± 0.90 mg/m3. It was below detection limit at E1, lowest at R1 and was significantly higher at R2 and R3 compared to others, probably due to additional emissions from the generating set.
      • Iyogun K.
      • Lateef S.A.
      • Ana G.R.E.E.
      Lung Function of Grain Millers Exposed to Grain Dust and Diesel Exhaust in Two Food Markets in Ibadan Metropolis, Nigeria.
      The average values of H2S (0.10 mg/m3) and SO2 (0.10 mg/m3) were within the recommended air quality standards of NESREA
      NESREA (National Environmental Standards and Regulations Enforcement Agency)
      National environmental (air quality control) regulation.
      and WHO.
      • World Health Organization
      WHO guidelines for indoor air quality: selected pollutants.
      Fine particulate matter (PM2.5) concentrations ranged from 97.90 ± 50.54 μg/m3 (M3) to 1469.70 ± 423.44 μg/m3 (E1). The variations in the level of PM2.5 at the different locations can be attributed to the poultry management systems. Pullets were raised on litter (wood shavings and dust) of 6 months, and bird activities in this system raised more dust. Bird activities usually increase the aerial dust concentration.
      • Heber A.J.
      • Lim T.T.
      • Gallien J.Z.
      • et al.
      • Huneau-Salaun A.
      • Guillam M.T.
      • Bouquin S.
      Aerial exposures of workers in poultry houses for laying hens and their impacts on respiratory health in europe.
      reported that ambient dust levels in on-floor systems were higher than those in cages. M2 and M3 had the lowest PM2.5 concentrations across the pens, because of combined mechanical and natural ventilation, while other pens had only natural ventilation. Therefore, increase in air velocity helps to disperse pollutants, and reduce their concentrations as observed in M1 and M2. The mean value of PM2.5 (337.28 ± 420.19 μg/m3) was however, higher than the air quality standards of NESREA
      NESREA (National Environmental Standards and Regulations Enforcement Agency)
      National environmental (air quality control) regulation.
      and WHO.
      • World Health Organization
      WHO guidelines for indoor air quality: selected pollutants.
      The air pollutants were generally measured at higher levels indoor than outdoor. The air pollutants of concern around and inside the poultry pens are CO2, CH4, NH3 and PM2.5. A strong relationship has been established between PM2.5 and human mortality in the US six cities.
      • Schwartz J.
      • Laden F.
      • Zanobetti A.
      The concentration–response relation between PM2.5 and daily deaths.
      Furthermore, a high level of particulate matter has been linked to increased adverse respiratory cardiac effects.
      USEPA
      ,
      • Taiwo A.M.
      Receptor Modelling of Industrial Air Pollutants.
      Human exposure to high level of NH3 through inhalation may result into bronchiolar and alveolar edema, nasopharyngeal and tracheal burns, and airway destruction resulting in respiratory failure.
      ATSDR (Agency for Toxic Substances and Disease Registry)
      Medical Management Guidelines for Ammonia.
      Furthermore, ailments such as headaches, hearing loss, sweating and fatigue, rapid pulse rate, and blood acidosis had been associated with exposure to high level of CO2.
      • Bierwirth P.N.
      Carbon Dioxide Toxicity and Climate Change: A Major Unapprehended Risk for Human Health.
      The health problems associated with CH4 are slurred speech, memory loss, nausea, mood changes, vision problems, facial flushing, vomiting, and headache.

      3.2 Effect of microclimatic parameters on the air pollutants

      Table S4 (in the supplementary information) shows the summary of microclimatic parameters at the poultry sites during the monitoring of the air quality. The relative humidity (RH) ranged from 32.75 ± 8.53 to 59.57 ± 11.44%. The highest and the lowest RH were obtained at M2 and E1 sites. The average relative humidity (51.39%) was within 50–70.0% as recommended by
      • Prodanov M.
      • Radeski M.
      • Ilieski V.
      Air quality measurements in laying hens housing.
      and.
      • Xiong Y.
      • Meng Q.
      • Gao J.
      • Tang X.
      • Zhang H.
      Effects of relative humidity on animal health and welfare.
      The average value of temperature ranged between 30.74 ± 3.50 and 34.08 ± 2.71 °C. The mean temperature measured (31.59 °C) during the study was similar to 32.8 °C obtained by
      • Nwagwu C.
      • Ede P.N.
      • Okoli I.C.
      • Chukwuka O.K.
      • Okoli G.C.
      Study on late rainy season aerial pollutant gases concentrations in tropical poultry pen environment in Nigeria.
      and
      • Hamid A.
      • Ahmad A.S.
      • Khan N.
      Respiratory and other health risks among poultry- farm workers and evaluation of management practices in poultry farms.
      at poultry pens during dry season/summer. The mean temperature was higher than the optimal temperature for animal welfare and performance recommended by.
      • Hulzebosch J.
      Effective heating systems for poultry houses.
      The high temperature may be attributed to the weather condition in the early months of dry season of the sampling period.
      • Nwagwu C.
      • Ede P.N.
      • Okoli I.C.
      • Chukwuka O.K.
      • Okoli G.C.
      Evaluation of aerial pollutant gases concentrations in poultry pen environments during early dry season in the humid tropical zone of Nigeria.
      Wind speed range at the poultry sites was between 0.05 ± 0.22 and 1.8 ± 0.9 m/s. This value may be linked to low or still air movement since temperature was high during sampling period. Pens M1 and M2 had significantly higher wind speed, which can be attributed to the combination of mechanical and natural ventilation system adopted compared to other pens. However, the mean wind speed value (0.54 ± 1.54 m/s) was lower than the 2.5–3.0 m/s recommended for poultry facilities by.
      • Dalolio F.S.
      • Nogueira da Silva J.
      • Albino L.F.T.
      • Moreira J.
      • Mendes L.B.
      Air pollution and their mitigation measures in Brazilian poultry production.
      The quantified relationships among relative humidity, temperature and wind speed on CO2, CH4, NO2, NH3, H2S, and SO2 and particulate matter (PM2.5) using regression analysis are presented in Table 2. Relative humidity had significance effect on PM2.5 and all the gases except NH3. Relative humidity had a negative relationship on NO2 and CH4, and this confirms the findings of.
      • Srivastava R.K.
      • Sarkar S.
      • Beig G.
      Correlation of various gaseous pollutants with meteorological parameter (temperature, relative humidity and rainfall).
      Relative humidity also had a negative effect on SO2. This finding agreed with the report of
      • Nwagwu C.
      • Ede P.N.
      • Okoli I.C.
      • Chukwuka O.K.
      • Okoli G.C.
      • Moreki J.C.
      Effect of environmental factors and structural dimensions on aerial pollutant gas concentrations in tropical poultry pen in Nigeria.
      who stated that as humidity increases, SO2 concentration in the pen decreases.
      Table 2Multiple regression analysis of microclimatic parameters on air pollutants.
      Air pollutants (Y)Prediction EquationCoefficient of Determination (R2)Coefficient of Correlation (R)Standard Error
      CO21192.46* + 4.550RH* + 1.661T–4.986WS0.6820.836253.419
      CH41.107* + 0.005RH* - 0.036T* + 0.009WS0.5830.7640.702
      NO20.032*-1.356E-5RH*+5.652E-5T*+6.839E-5WS*0.7540.8630.001
      NH35.851* + 0.001RH-0.115T*-0.081WS*0.8340.9131.606
      H2S−0.217 + 0.003RH*+0.005T-0.018WS**0.1850.4270.421
      SO2−0.453* + 0.003RH*+0.013T*-0.019WS*0.2580.5080.413
      PM2.5−1.727-3.802RH*+17.021T*-5.899WS***0.5470.740409.202
      RH- Relative Humidity; T-Temperature; WS-Wind speed; *Significant at p < 0.01; **Significant at p < 0.05 ***Significant at p < 0.10.
      Temperature has no significant effect on CO2 and H2S concentrations. Temperature has a positive correlation with CH4 as previously documented by.
      • Srivastava R.K.
      • Sarkar S.
      • Beig G.
      Correlation of various gaseous pollutants with meteorological parameter (temperature, relative humidity and rainfall).
      Temperature also has a positive relationship with PM2.5. PM2.5 is usually positively correlated with the concentration of airborne particles as reported in previous studies by
      • Gustafsson G.
      • Von Wachenfelt E.
      Airborne dust control measures for floor housing system for laying hens.
      and.
      • Nimmermark S.
      • Lund V.
      • Gustafsson G.
      • Eduard W.
      Ammonia, dust and bacteria in welfare-oriented systems for laying hens.
      Wind speed was anti-correlated with PM2.5, NO2, NH3, H2S and SO2. Thus, increase in wind speed has a significant reduction on the concentrations of PM2.5, NO2, NH3, H2S and SO2. High ventilation rates decrease the indoor dust concentration by dilution. In most studies, this relationship has been observed stating that increased ventilation may also dilute the indoor gaseous and dust concentration especially in dry season.
      • Mostafa W.
      • Buescher W.
      Indoor air quality improvement from particle matters for laying hen poultry houses.
      ,
      • Kilic I.
      • Yaslioglu E.
      Ammonia and carbon dioxide concentrations in a layer house.
      This also conforms to the studies of
      • Xu W.
      • Zheng K.
      • Meng L.
      • et al.
      Concentrations and emissions of particulate matter from intensive pig production at a large farm in North China.
      who also observed decreased indoor PM concentrations at increasing ventilation rate and indoor relative humidity.

      3.3 Socio-demographic, work, and farm characteristics of poultry workers

      The socio-demographic and farm characteristics of the respondents are shown in Table 3b, Table 3c, Table 3aa–c . The large fractions of the poultry workers were 21–30 years, which is a productive age. This shows that youths were more involved in poultry production, similar to the past study of.
      • Ajetomobi J.O.
      • Ajagbe F.A.
      • Adewoye J.O.
      Occupational hazards and productivity of poultry farmers in osun state of Nigeria.
      Most respondents were male (84.2%). Poultry activities are labour intensive, hence mostly dominated by young men, which are perceived to have more strength for such activities. About 68.4% of the respondents were single, while 26.3% were married. Most of the poultry workers were youths (30 years) who are yet to start a family. This study also revealed that most of the poultry workers attended secondary school (73.7%) similar to the study of.
      • Adebowale O.O.
      • Adeyemo O.
      Assessment of workplace health and safety measures among poultry workers in a southwestern state of Nigeria.
      Good education is important in poultry operation to handle challenges and make certain decisions in the management of the poultry.
      Table 3aSocio-demographic characteristics of poultry workers.
      CharacteristicsFrequencyPercentage (%)
      Age of respondent (years)
      <20821.1
      21–302155.3
      31–40718.4
      >5125.3
      Gender
      Male3284.2
      Female615.8
      Marital status
      Married1026.3
      Single2668.4
      Separated25.3
      Education
      Primary615.8
      Secondary2873.7
      Tertiary410.5
      Smoking status
      Smokers37.9
      Non- smokers3592.1
      Table 3bWork characteristics of poultry workers.
      CharacteristicsFrequencyPercentage (%)
      Workers' residence
      On- farm3284.2
      Off- farm615.8
      Work experience(years)
      ≤11847.4
      1.01–4.001334.2
      4.01–7.0037.9
      ≥7.01410.5
      Work hours per week
      11–201642.1
      ≥402257.9
      Workdays per week
      62360.5
      71539.5
      Primary poultry activity
      Feeding3284.2
      Egg collection615.8
      Exposure to dust
      Mild1231.6
      Moderate2257.9
      Severe410.5
      Use of respiratory protection
      Never3284.2
      Sometimes615.8
      Importance of PPE for health protection
      Somewhat important37.9
      Very important3592.1
      Table 3cCharacteristics of poultry farms.
      CharacteristicFrequencyPercentage (%)
      Age of farm (years)
      ≤61436.8
      ≥102463.2
      Poultry type
      Broilers1026.3
      Layers2668.4
      Pullet25.3
      Number of birds
      ≤5000410.5
      5001–100001744.7
      10000–150001026.5
      ≥20001718.4
      Poultry management type
      Litter821.2
      Battery cage2568.8
      Both513.2
      Frequency of waste disposal
      ≤1 week2668.4
      Fortnightly25.3
      Monthly821.1
      >2 months25.3
      The work characteristics of respondents are presented in Table 3b. Most of the workers resided on the farm (84.2%) and only 15.8% lived off-farm. About 47.0% of the poultry workers had less than one-year work experience, while 34.2, 7.9 and 10.5% had working experience of 1–4, 4–7 and over 7 years, respectively. Less than 50.0% worked 11–20 h per week, while more than half of the workers (57.9%) worked for at least 40 h per week. Over 60.0% worked 6 days/week, while 39.5% worked 7 days/week.
      The farm characteristics of the respondents are shown in Table 3c. Approximately 63.2% worked in farms that were more than 10 years in poultry operations; out of which 68.4% were raising layers, 26.3% broilers and 5.3% pullets. Layers formed a higher percentage breed of birds than broilers in Nigeria.
      • Adebowale O.O.
      • Adeyemo O.
      Assessment of workplace health and safety measures among poultry workers in a southwestern state of Nigeria.
      About half of the respondents (44.7%) were from the poultry farm size having birds between 5001 and 10,000, while the least fraction of the respondents (10.5%) had birds below 5000. Battery cage system was operated by many of the poultry farmers (68.8%); 21.2% operated litter management system, while 13.2% operated both management types. About 68.4% of the farms disposed wastes weekly, 21.1% monthly, 5.3% fortnightly, and 5.3% for more than two months.
      The primary poultry activity by 84.2% of the workers mostly males was feeding of birds, while the main poultry activity engaged by the females (15.8%) was egg collection. Other activities the workers engaged in include litter filling, litter removal, sweeping and cleaning of pen and manure disposal.
      The highest percent of dust exposure reported by the workers was moderate (57.9%), only 10.5% reported a severe exposure to dust. Although, 92.1% stated that it was important to use Personal Protective Equipment (PPE); approximately 84% had never used PPE, while only 15.8% used it sometimes.
      The study of
      • Adebowale O.O.
      • Adeyemo O.
      Assessment of workplace health and safety measures among poultry workers in a southwestern state of Nigeria.
      showed that 8.4% of poultry workers had a complete set of PPE for use in poultry farms in Ogun State. The use of appropriate respiratory protection equipment is a prevention measure for the workers to avoid exposure to pollutants, which potentially affect their health.
      • Kearney G.D.
      • Shaw R.
      • Prentice M.
      • Tutor-Marcom R.
      Evaluation of respiratory symptoms and respiratory protection behaviour among poultry workers in small farming operations.
      However, many workers do not use it, probably due to physical inconveniences, ignorance, or personal choices.
      • Carruth A.K.
      • Duthu S.G.
      • Levin J.
      • Lavigne T.
      Behavior change, environmental hazards and respiratory protection among a southern farm community.

      3.4 Respiratory symptoms among poultry workers

      Respiratory symptoms reported by the workers are shown in Fig. 2. This indicated that almost half of workers had dry cough (47.4%), cough with phlegm (39.5%), nasal irritation (71.1%) and throat irritation (31.6%). A similar result was reported by
      • Kearney G.D.
      • Shaw R.
      • Prentice M.
      • Tutor-Marcom R.
      Evaluation of respiratory symptoms and respiratory protection behaviour among poultry workers in small farming operations.
      in his evaluation of respiratory symptoms among 32 poultry workers in North Carolina, USA. Nasal irritation (71.1%) indicates a high prevalence of respiratory symptom, which is expression of airways inflammation.
      • Rylander R.
      • Fernan da Carvalheiro M.
      Airways inflammation among workers in poultry houses.
      • Radon K.
      • Weber C.
      • Iversen M.
      • Danuser B.
      • Pedersen S.
      • Nowak D.
      Exposure assessment and lung function in pig and poultry farmers.
      also reported airway narrowing or irritation, shortness of breath, wheezing, and dry cough in workers.
      Fig. 2
      Fig. 2Reported symptoms and characteristics of poultry workers.
      Eye irritation was experienced by 47.7% of the workers, corresponding to the report of
      • Omland O.
      Exposure and respiratory health in farming in temperate zones – a review of the literature.
      for 72 workers in Denmark. Reason may be linked to exposure to dusts from feed by workers that could irritate the eye and nose.
      HSE
      About 73.7% of the workers stated that their breathing improved when away from work; this suggests an association of respiratory disturbances with working activities, corresponding to the report of
      • Viegas S.
      • Faísca V.M.
      • Dias H.
      • Clérigo A.
      • Carolino E.
      • Viegas C.
      Occupational exposure to poultry dust and effects on the respiratory system in workers.
      among 47 poultry workers in Portugal.
      Other major symptoms reported by the workers include dizziness (50.0%), headache and pains (86.8%), tiredness (86.8%). These are systemic symptoms of airways inflammation disease, which are likely caused by inflammatory mediators produced in the lung after inhalation and distributed to different parts of the body via the blood.
      • Okiki P.A.
      • Ogbimi A.O.
      • Edafiadhe W.E.
      Effects of air-borne hazards on the physical and psychological health of Nigerian poultry workers.
      ,
      • Michel O.
      • Duchateau J.
      • Plat G.
      • et al.
      Blood inflammatory response to inhaled endotoxin in normal subjects.

      3.5 Lung function assessment of poultry workers and control group

      The spirometry lung function test of poultry workers and control group are presented in Table 4. There was significant variation (p > 0.05) in the mean anthropometric characteristics of the poultry workers and control group. Both groups were mostly men, 76.7% for poultry workers and 76.7% for control (all participants were within the range of 21–30 years). Most of the poultry workers weighed 51–60 kg (43.3%) and were 161–170 cm (27.5%) tall, while the control group weighed 51–60 kg (47.6%) and 161–170 cm (27.5%) in height. There was also no significant difference (p > 0.05) in the anthropometric variables (height and weight) between the two groups as observed by.
      • Iyogun K.
      • Lateef S.A.
      • Ana G.R.E.E.
      Lung Function of Grain Millers Exposed to Grain Dust and Diesel Exhaust in Two Food Markets in Ibadan Metropolis, Nigeria.
      Table 4Lung function status among poultry workers and control group.
      Poultry workersControlP- value
      N(%)MeanN(%)Mean
      Age of respondent (years)26.53 ± 6.9425.93 ± 4.15NS
      <20516.7310
      21–352376.71550
      36–5013.3723.3
      >5113.3516.7
      Gender
      Male2376.72376.7
      Female723.3723.3
      Weight (kg)60.6 ± 7.7960.97 ± 7.01NS
      5031026.7
      51–601343.31447.6
      61–7012401240
      <7126.726.7
      Height (cm)163.1 ± 9.05162.33 ± 7.72NS
      ≤150410410
      151–160820820
      161–1701127.51127.5
      171717.5717.5
      FVC (% of predicted)
      Normal246099.96 ± 30.642376.7100.11 ± 122.71NS
      Mild12.513.3
      Moderate12.5620
      Severe410
      FEV1(% of predicted)99.94 ± 36.76107.16 ± 23.76NS
      Normal2152.52480
      Mild37.5620
      Moderate37.5
      Severe37.5
      FEV1/FVC86.84 ± 18.3298.82 ± 1.52S
      Obstructive310
      Normal279030100
      PEFR (% of predicted)61.12 ± 27.85588.41 ± 21.76S
      Normal1756.72996.7
      Mild93013.33
      Severe413.3
      NS- Not significant, S- significant at p < 0.05.
      Spirometry parameters were determined to assess the lung function of 30 poultry workers and controls with exclusion of smokers, and those with a history of asthma. Table 4 shows significant variation in FVC and FEV1 in both groups. FEV1 measured as a percent of the predicted, had a mean 107.16 ± 23.76 l for the control group and 99.94 ± 36.76 l for poultry workers. It was observed that 80% of the control group had normal FEV1 condition with no moderate or severe lung reduction, unlike the poultry workers with only 52.5% showing normal lung condition.
      The lung function test indicates that the mean FVC percent of the predicted is 100.11 ± 122.7 1, with 76.7% having normal lung function, while the poultry workers had 60.0% with normal condition. The FEV1/FVC (86.84 ± 18.32 l) of the poultry workers was significantly lower than the control group (98.82 ± 1.52 l). The FEV1/FVC showed that only 10.0% of the poultry workers had obstructive lung function pattern, while the control group showed a 100% normal lung function (Fig. S1, in the supplementary information). The predicted PEFR percentage was normal for 96.67% of the control group, while only 56.67% of the poultry workers had a normal pattern, indicating a constricted lung airway for others. The predicted mean PEFR value (61.12 ± 27.86%) of poultry workers was significantly lower than that of the control group (88.41 ± 21.76%) corresponding to the observation of.
      • Akanbi O.G.
      • Ismaila O.
      • Olaoniye W.
      • Oriolowo K.T.
      • Odusote A.
      Assessment of post-work peak expiratory flow rate of workers in cement company.
      There was no statistical significance in the observed and predicted FVC and FEV1values, while PEF and FEV1/FVC (%) levels were significant (Table S5, in the supplementary information). It was observed that FVC, which is the maximal amount of air that can be exhaled following a maximal inspiratory effort in poultry workers, was 2.03 L higher than the predicted value of 1.92 L. The average FVC in poultry workers was 99.64% of the predicted value. In the control group the FVC observed was the same as the predicted value of 1.87 L. The average FVC of control group was 100% of the predicted value.
      FEV1, which is the volume of air exhaled in a 1 s during a forced vital capacity effort in poultry workers (1.76 L) was more than the predicted (1.74 L); these values were 1.84 and 1.72 L, respectively in control group. The FEV1 in poultry workers was 99.94% of the predicted value and 106.98% in control group. The mean % predicted FEV1 of the control group was significantly higher than those of the poultry workers. This was similarly observed by
      • Mustajbegovic J.
      • Zuskin E.
      • Schachter E.N.
      • et al.
      Respiratory findings in livestock farm-workers.
      in farmers and the controls.
      Although the FEV1 was significantly higher in control group than the poultry workers; the ratio values above 80% suggest the incidence of minimal obstructive lung function for both groups.
      • Hamid A.
      • Ahmad A.S.
      • Khan N.
      Respiratory and other health risks among poultry- farm workers and evaluation of management practices in poultry farms.
      ,
      • Viegas S.
      • Faísca V.M.
      • Dias H.
      • Clérigo A.
      • Carolino E.
      • Viegas C.
      Occupational exposure to poultry dust and effects on the respiratory system in workers.
      The predicted mean PEFR data of the poultry workers was significantly lower than the control group similar to the study of
      • Akanbi O.G.
      • Ismaila O.
      • Olaoniye W.
      • Oriolowo K.T.
      • Odusote A.
      Assessment of post-work peak expiratory flow rate of workers in cement company.
      who established higher peak flow values when workers were well, and lower values, when the airways were constricted. This also aligns with the research work of.
      • Kirychuk S.P.
      • Senthilselvan A.
      • Dosman J.A.
      • et al.
      Respiratory symptoms and lung function in poultry confinement workers in Western Canada.
      The difference in pulmonary function between the two groups can be associated with the possibility of work-related respiratory symptoms.
      • Woldeamanuel G.G.
      • Mingude A.B.
      • Yitbarek G.Y.
      • Taderegew M.M.
      Chronic respiratory symptoms and pulmonary function status in Ethiopian agricultural workers: a comparative study.
      A significance difference (p < 0.05) observed in PEFR between poultry workers and the control group indicates an evident reduction in PEFR values among poultry workers. This also signifies increased respiratory symptoms, because of exposure to respiratory hazards in their work environment.
      • Olujimi O.O.
      • Ana G.R.E.E.
      • Ogunseye O.O.
      • Fabunmi V.T.
      Air quality index from charcoal production sites, carboxyheamoglobin and lung function among occupationally exposed charcoal workers in south western Nigeria.
      ,
      • Tzanakis N.
      • Kallergis K.
      • Bouros D.E.
      • Samiou M.F.H.
      • Siafakas N.M.
      Short-term effects of wood smoke exposure on the respiratory system among charcoal production workers.

      4. Conclusion

      The assessment of air quality around the poultry farms revealed higher levels of CO2, CH4, NH3 and PM2.5 than the permissible limits of the NESREA indicating unsafe environment. The microclimatic parameters measured during the study were below the recommended standards in most pens across all zones. Correlation coefficient between air pollutants and microclimatic parameters were relatively low. This study also showed that poultry workers are more vulnerable to respiratory symptoms, because of their exposure to pollutants in their work environment. The respiratory symptoms reported by most respondents were dry cough, cough with phlegm, nasal irritation and throat irritation. These symptoms indicate airway inflammation exposing most workers to chronic bronchitis.
      The assessment of lung function recorded lower observed and predicted values of FEV1, FVC, FEV1/FVC and PEFR in poultry workers compared to the control group. The comparison of lung function parameters between poultry workers and non-poultry workers indicated that poultry workers have more lung impairment and experienced airway obstructions resulting from exposure to air pollutants in poultry work environment than the non-poultry workers.
      This study therefore recommends that poultry owners and workers must adopt the necessary management practices and strategies for their production to create and improve the air quality in the pens. They should also be provided with necessary Personal Protection Equipment (PPE). Periodic lung function assessment of persons involved in poultry production is important to know the health status of the poultry workers.

      Funding

      None.

      Authors' contributions

      TAA, AMT and TFA designed and supervised the study. TJO collected the data, and drafted the manuscript. LOO assisted in data collection and technical issue. All the authors read and approved the manuscript.

      Declaration of competing interest

      None.

      Acknowledgements

      The authors acknowledged the financial support from the Centre of Excellence for Agricultural Development and Sustainable Environment (CEADESE), Federal University of Agriculture, Abeokuta. We appreciate Dr Femi Oyediran, the Principal Consultant of Environmental Laboratory Limited, for the assistance rendered during the field sampling. We are also grateful to the management and members of staff of the Poultry Farms used for this study.

      Appendix A. Supplementary data

      The following is the Supplementary data to this article:

      References

        • Sahel
        An Assessment of the Nigerian Poultry Sector.
        (Volume 11)
        www.sahelcp.com
        Date: 2015
        Date accessed: January 24, 2020
        (Accessed)
        • Copeland C.
        Air Quality Issues and Animal Agriculture: A Primer.
        Congressional Research Service Report, 2014
        • Olanrewaju H.A.
        • Dozier W.A.
        • Purswell J.L.
        • et al.
        Growth performance and physiological variables for broiler chickens subjected to short-term elevated carbon dioxide concentrations.
        Int J Poultry Sci. 2008; 7: 738-742
        • Taiwo A.M.
        • Arowolo T.A.
        • Adekunle I.M.
        • Adetunji M.T.
        Evaluating the environmental impacts of poultry farming on stream water quality: a study from Abeokuta, Nigeria.
        Environ Qual Manag. 2013; 22: 79-93
        • Kocaman B.
        • Yaganoglu A.V.
        • Yanar M.
        Combination of fan ventilation system and spraying of oil-water mixture on the levels of dust and gases in caged layer facilities in Eastern Turkey.
        J Appl Anim Res. 2005; 27: 109-111https://doi.org/10.1080/097121 19.2005.9706551
        • Liang Y.
        • Xin H.
        • Li H.
        • et al.
        Ammonia Emissions from U.S. Laying Hen Houses in Iowa and Pennsylvania.
        2005
        • Fournel S.
        • Pelletier F.
        • Godbout S.
        • Lagace R.
        • Feddes J.J.R.
        Odour emissions, hedonic tones and ammonia emissions from three cage layer housing systems.
        Biosyst Eng. 2012; 112: 181-191
        • IPPC
        Integrated Pollution Prevention and Control) Reference Document on Best Available Techniques for Intensive Rearing of Poultry and Pigs.
        2016 (Available online:) (Accessed on)
        • Pereira J.L.S.
        Assessment of ammonia and greenhouse gas emissions from broiler houses in Portugal.
        Atmos Pollut Res. 2017; 8: 949-955https://doi.org/10.1016/j.apr.2017.03.011
        • Heber A.J.
        • Lim T.T.
        • Gallien J.Z.
        • et al.
        Quality Assured Measurement of Animal Building Emissions: Part 2. Particulate Matter Concentrations. Symposium on Air Quality Measurement Methods and Technology. AWMA (Pittsburgh, PA), San Francisco, CA2002 (November 13-25)
        • Robarge W.P.
        • Walkerb J.T.
        • McCulloch R.B.
        • Murray G.
        Atmospheric concentrations of ammonia and ammonium at an agricultural site in the southeast United States.
        Atmos Environ. 2002; 36: 1661-1674
        • Baek B.H.
        • Aneja V.P.
        Measurement and analysis of the relationship between ammonia, acid gases, and fine particles in eastern North Carolina.
        J Air Waste Manag Assoc. 2004; 54: 623-633
        • Barreiro T.J.
        • Perillo I.
        An Approach to Interpreting Spirometry.
        Ame Family Phys. 2004; 169: 1107-1114
        • Akanbi O.G.
        • Ismaila O.
        • Olaoniye W.
        • Oriolowo K.T.
        • Odusote A.
        Assessment of post-work peak expiratory flow rate of workers in cement company.
        Sigurnost. 2014; 56: 315-322
        • Iversen M.
        • Kirychuk S.
        • Drost H.
        • Jacobson L.
        Human health effects of dust exposure in animal confinement buildings.
        J Agric Saf Health. 2000; 6: 283-288
        • Adebowale O.O.
        • Adeyemo O.
        Assessment of workplace health and safety measures among poultry workers in a southwestern state of Nigeria.
        Italian J Occup Environ Hygiene. 2016; 7: 66-71
      1. Hawkes C. Ruel M.T. Understanding the Links between Agriculture and Health. International Food Policy Research Institute, Washington, DC2020 (Accessed)
        • Najjar Y.S.
        Gaseous pollutants formation and their harmful effects on health and environment.
        Innov Energy Policies. 2011; 1: 1-9
        • Taiwo A.M.
        • Harrison R.M.
        • Shi Z.
        A review of receptor modelling of industrially emitted particulate matter.
        Atmos Environ. 2014; 97: 109-120
        • Taiwo A.M.
        Characteristics of particulate matter collected at an urban background site and a roadside site in Birmingham, United Kingdom.
        Atmósfera. 2017; 30: 323-335
        • Nwagwu C.
        • Ede P.N.
        • Okoli I.C.
        • Chukwuka O.K.
        • Okoli G.C.
        Study on late rainy season aerial pollutant gases concentrations in tropical poultry pen environment in Nigeria.
        Inter J Tropical Agric Food Syst. 2010; 4: 188-194
        • Okiki P.A.
        • Ogbimi A.O.
        • Edafiadhe W.E.
        Effects of air-borne hazards on the physical and psychological health of Nigerian poultry workers.
        J Biol Agric Healthcare. 2013; 3: 102-110
        • Uyo C.N.
        • Njoku J.D.
        • Iwuji M.C.
        • Ihejirika C.E.
        • Njoku-Tony R.F.
        Assessment of air quality in livestock farms and abattoirs in selected LGAs of Imo State.
        Inter J Adv Acad Res. 2021; 7: 54-68
        • Nwagwu C.
        • Ede P.N.
        • Okoli I.C.
        • Chukwuka O.K.
        • Okoli G.C.
        Evaluation of aerial pollutant gases concentrations in poultry pen environments during early dry season in the humid tropical zone of Nigeria.
        Nat Sci. 2011; 9: 37-42
        • Ogun State Government
        Ogun State Brief.
        2021
        https://www.ogunstate.gov.ng/ogun-state/
        Date accessed: August 25, 2021
        (Accessed)
        • Miller M.R.
        • Hankinson J.A.T.S.
        • Brusasco V.
        • et al.
        Standardisation of spirometry.
        Eur Respir J. 2005; 26: 319-338
        • Reddy U.N.
        • Khan M.A.U.
        • Anjum S.
        • et al.
        Evaluation of mean peak expiratory flow rate (PEFR) of healthy children belonging to urban areas of hyderabad.
        Asian Pac J Health Sci. 2014; 1 (2014): 113-119
        • Olujimi O.O.
        • Ana G.R.E.E.
        • Ogunseye O.O.
        • Fabunmi V.T.
        Air quality index from charcoal production sites, carboxyheamoglobin and lung function among occupationally exposed charcoal workers in south western Nigeria.
        SpringerPlus. 2016; 5: 1-18
        • Pellegrino R.
        • Viegi G.
        • Brusasco V.
        Interpretative strategies for lung function tests.
        Eur Respir J. 2005; 26: 948-968
        • Ibhafidon L.I.
        • Obaseki D.O.
        • Erhabor G.E.
        • Akor A.A.
        • Irabor I.
        • Obioh I.B.
        Respiratory symptoms, lung function and particulate matter pollution in residential indoor environment in ile-ife, Nigeria.
        Niger Med J. 2014; 55: 48-53
        • Lopez J.R.
        • Somsamouth K.
        • Mounivong B.
        • et al.
        Environmental exposures, lung function and respiratory health in rural Lao PDR.
        Southeast Asian J Trop Med Publ Health. 2014; 45 (198–06)
        • Obayelu A.E.
        • Adeniyi A.
        The effect of climate on poultry productivity in ilorin kwara state, Nigeria.
        Int J Poultry Sci. 2006; 5: 1061-1068
        • Nwagwu C.
        • Ede P.N.
        • Okoli I.C.
        • Chukwuka O.K.
        • Okoli G.C.
        • Moreki J.C.
        Effect of environmental factors and structural dimensions on aerial pollutant gas concentrations in tropical poultry pen in Nigeria.
        Inter J Applied Poultry Res. 2012; 1: 15-20
        • World Health Organization
        WHO guidelines for indoor air quality: selected pollutants.
        in: World Health Organization. Regional Office for Europe. 2010 (Accessed)
        • Guarrasi J.
        • Trask C.
        • Kirychuk S.A.
        Systematic review of occupational exposure to hydrogen sulphide in livestock operations.
        J Agromed. 2015; 20: 225-236
        • Iyogun K.
        • Lateef S.A.
        • Ana G.R.E.E.
        Lung Function of Grain Millers Exposed to Grain Dust and Diesel Exhaust in Two Food Markets in Ibadan Metropolis, Nigeria.
        Safety Health Work, 2018: 1-7https://doi.org/10.1016/j.shaw.2018.01.002
        • Huneau-Salaun A.
        • Guillam M.T.
        • Bouquin S.
        Aerial exposures of workers in poultry houses for laying hens and their impacts on respiratory health in europe.
        World Poultry Sci J. 2013; 69: 15-19
        • Schwartz J.
        • Laden F.
        • Zanobetti A.
        The concentration–response relation between PM2.5 and daily deaths.
        Environ Health Perspect. 2002; 110: 1025-1029
        • USEPA
        Air Quality Criteria for Particulate Matter. ume I. U.S. Environmental Protection Agency, Research Triangle Park, NC2004
        • Taiwo A.M.
        Receptor Modelling of Industrial Air Pollutants.
        (PhD Thesis) Division of Environmental Health Risk Management, University of Birmingham, United Kingdom2013: 408p
        • ATSDR (Agency for Toxic Substances and Disease Registry)
        Medical Management Guidelines for Ammonia.
        2014 (Accessed)
        • Bierwirth P.N.
        Carbon Dioxide Toxicity and Climate Change: A Major Unapprehended Risk for Human Health.
        2018 (Accessed)
        • Public Health
        England methane general information.
        (20019) (7th December 2020)
        • Prodanov M.
        • Radeski M.
        • Ilieski V.
        Air quality measurements in laying hens housing.
        Maced Vet Rev. 2016; 39: 91-95https://doi.org/10.1515/macvetrev-2016-0071
        • Xiong Y.
        • Meng Q.
        • Gao J.
        • Tang X.
        • Zhang H.
        Effects of relative humidity on animal health and welfare.
        J Integr Agric. 2017; 16: 60345-60347
        • Hamid A.
        • Ahmad A.S.
        • Khan N.
        Respiratory and other health risks among poultry- farm workers and evaluation of management practices in poultry farms.
        Brazil J Poultry Sci. 2018; 20: 111-118
        • Hulzebosch J.
        Effective heating systems for poultry houses.
        World Poultry Sci J. 2006; 2: 18-19
        • Dalolio F.S.
        • Nogueira da Silva J.
        • Albino L.F.T.
        • Moreira J.
        • Mendes L.B.
        Air pollution and their mitigation measures in Brazilian poultry production.
        Afr J Agric Res. 2015; 10: 4522-4531
        • Srivastava R.K.
        • Sarkar S.
        • Beig G.
        Correlation of various gaseous pollutants with meteorological parameter (temperature, relative humidity and rainfall).
        Glob J Sci Front Res (GJSFR): H Environ Earth Sci. 2014; 14: 57-65
        • Gustafsson G.
        • Von Wachenfelt E.
        Airborne dust control measures for floor housing system for laying hens.
        in: Paper Presented at the VIII Agricultural Engineering International Conference. 2006
        • Nimmermark S.
        • Lund V.
        • Gustafsson G.
        • Eduard W.
        Ammonia, dust and bacteria in welfare-oriented systems for laying hens.
        Ann Agric Environ Med. 2009; 16: 103-113
        • Mostafa W.
        • Buescher W.
        Indoor air quality improvement from particle matters for laying hen poultry houses.
        Biosyst Eng. 2011; 109: 22-36
        • Kilic I.
        • Yaslioglu E.
        Ammonia and carbon dioxide concentrations in a layer house.
        Asian Australas. J Animal Sci. 2014; 27: 1211-1218
        • Xu W.
        • Zheng K.
        • Meng L.
        • et al.
        Concentrations and emissions of particulate matter from intensive pig production at a large farm in North China.
        Aerosol Air Qual Res. 2016; 16: 79-90
        • Ajetomobi J.O.
        • Ajagbe F.A.
        • Adewoye J.O.
        Occupational hazards and productivity of poultry farmers in osun state of Nigeria.
        Int J Poultry Sci. 2010; 9: 330-333
        • Kearney G.D.
        • Shaw R.
        • Prentice M.
        • Tutor-Marcom R.
        Evaluation of respiratory symptoms and respiratory protection behaviour among poultry workers in small farming operations.
        J Agromed. 2014; 19: 162-170https://doi.org/10.1080/1059924X.2014.886536
        • Carruth A.K.
        • Duthu S.G.
        • Levin J.
        • Lavigne T.
        Behavior change, environmental hazards and respiratory protection among a southern farm community.
        J Agromed. 2008; 13: 49-58
        • Rylander R.
        • Fernan da Carvalheiro M.
        Airways inflammation among workers in poultry houses.
        Int Arch Occup Environ Health. 2006; 79: 487-490
        • Radon K.
        • Weber C.
        • Iversen M.
        • Danuser B.
        • Pedersen S.
        • Nowak D.
        Exposure assessment and lung function in pig and poultry farmers.
        Occup Environ Med. 2001; 8: 405-410
        • Omland O.
        Exposure and respiratory health in farming in temperate zones – a review of the literature.
        Ann Agric Environ Med. 2002; 9: 119-136
        • HSE
        Controlling Exposure to Poultry Dust: An Occupational Hygiene Standard of Good Working Practice for Poultry Farmers. 2009 (03/09-WEB39) (Accessed 20th March, 2018)
        • Viegas S.
        • Faísca V.M.
        • Dias H.
        • Clérigo A.
        • Carolino E.
        • Viegas C.
        Occupational exposure to poultry dust and effects on the respiratory system in workers.
        J Toxicol Environ Health, Part A. 2013; 76: 230-239
        • Michel O.
        • Duchateau J.
        • Plat G.
        • et al.
        Blood inflammatory response to inhaled endotoxin in normal subjects.
        Clin Exp Allergy. 1995; 25: 73-79
        • Mustajbegovic J.
        • Zuskin E.
        • Schachter E.N.
        • et al.
        Respiratory findings in livestock farm-workers.
        J Environ Manag. 2001; 43: 576-584
        • Kirychuk S.P.
        • Senthilselvan A.
        • Dosman J.A.
        • et al.
        Respiratory symptoms and lung function in poultry confinement workers in Western Canada.
        Can Res J. 2003; 10: 375-380
        • Woldeamanuel G.G.
        • Mingude A.B.
        • Yitbarek G.Y.
        • Taderegew M.M.
        Chronic respiratory symptoms and pulmonary function status in Ethiopian agricultural workers: a comparative study.
        BMC Pulm Med. 2020; 20: 1-9
        • Tzanakis N.
        • Kallergis K.
        • Bouros D.E.
        • Samiou M.F.H.
        • Siafakas N.M.
        Short-term effects of wood smoke exposure on the respiratory system among charcoal production workers.
        Chest. 2001; 119: 1260-1265
        • NESREA (National Environmental Standards and Regulations Enforcement Agency)
        National environmental (air quality control) regulation.
        • NPC (National Population Commission)
        Bulletins on Population Census Figures.
        2006