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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.
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.
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.
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.
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.
The concentrations and emissions of dust particles from the livestock activities are generally determined by the characteristics of the adopted housing system.
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
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.
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.
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.
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.
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.
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. 1Map of Ogun State, Nigeria, showing the sampled pens in the study area.
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
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.
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.
Air quality index from charcoal production sites, carboxyheamoglobin and lung function among occupationally exposed charcoal workers in south western Nigeria.
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.
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.
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.
Table 1Mean concentrations of air pollutants in poultry sites.
Sampled Locations
CO2 (mg/m3)
CH4 (mg/m3)
NO2 (mg/m3)
NH3 (mg/m3
H2S ((mg/m3)
SO2 (mg/m3)
PM2.5 (μg/m3)
M1 (indoor)
1545.65 ± 279.30a
0.81 ± 1.37a
0.03 ± 0.001b
2.73 ± 1.86ab
0.04 ± 0.05c
0.03 ± 0.78b
222.94 ± 228.46c
M2 (indoor)
1466.82 ± 295.91a
0.06 ± 0.40b
0.03 ± 0.001b
2.00 ± 1.5c
0.34 ± 0.83b
0.33 ± 0.06b
222.77 ± 259.26c
M3 (outdoor)
1273.52 ± 221.7b
BDL
0.03 ± 0.001b
BDL
0.02 ± 0.02c
0.04 ± 0.05b
97.90 ± 50.54d
R1 (indoor)
1493.94 ± 206.81a
BDL
0.03 ± 0.001c
2.38 ± 1.36b
0.02 ± 0.03c
0.01 ± 0.01b
434.39 ± 399.05b
R2 (indoor)
1476.04 ± 262.18a
0.18 ± 0.45b
0.03 ± 0.001b
2.20 ± 1.48c
0.4 ± 0.88a
0.38 ± 0.83a
269.92 ± .241.61b
R3 (outdoor)
1303.97 ± 128.82b
BDL
0.03 ± 0.001b
0.23 ± 0.43e
0.33 ± 0.67b
0.44 ± 0.90a
125.61 ± 91.63d
E1 (indoor)
1353.22 ± 225.0b
BDL
0.03 ± 0.002a
1.36 ± 1.12d
BDL
BDL
1469.70 ± 423.44a
E2 (indoor)
1475.17 ± 264.85a
BDL
0.03 ± 0.001b
3.04 ± 1.64a
0.02 ± 0.03c
0.04 ± 0.9b
321.88 ± .278.52b
E3(outdoor)
1353.19 ± 226.03b
BDL
0.03 ± 0.001b
0.25 ± 0.44e
BDL
0.01 ± 0.03b
179.07 ± 212.98d
Mean
1476.04
0.20
0.03
2.22
0.10
0.10
337.28
SD
262.18
0.72
0.001
1.67
0.42
0.42
420.19
Range
1273.52–1545.65
0.06-0.81
0.032-0.034
0.23-3.04
0.02-0.4
0.01-0.44
97.90–1469.70
NESREA (2020)
NA
NA
0.04-0.06
0.3
0.10
0.10
250
WHO (2005)
900
0.06
0.11
0.19
0.06
25
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)
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
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
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.
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.
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
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
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.
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.
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.
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
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
at poultry pens during dry season/summer. The mean temperature was higher than the optimal temperature for animal welfare and performance recommended by.
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.
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.
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
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.
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.
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.
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.
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.
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.
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
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.
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
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.
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.
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.
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
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.
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.
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.
Air quality index from charcoal production sites, carboxyheamoglobin and lung function among occupationally exposed charcoal workers in south western Nigeria.
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:
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)
Air quality index from charcoal production sites, carboxyheamoglobin and lung function among occupationally exposed charcoal workers in south western Nigeria.
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