Distribution Characteristics Of Particulate Matter And Microbial Aerosol In Different Types Of Pigsties

In recent years,with the increasing intensification of animal husbandry,the problem of air pollution in livestock and poultry houses is becoming more and more serious due to the high feeding density.Microbial aerosols,particulate matter(PM)and harmful gases are the main air pollutants in livestock houses,which adversely affecting the health of the workers,the welfare of the animals and the surrounding environment.Recently,there are few studies on the analysis and comparison of the concentration of air pollutants in different types of pigsties,especially on the concentration analyze and types of microbial aerosols and particulate matter in pregnancy house,maternity house and nursery house.The purpose of this study was to investigate the distribution characteristics of microbial aerosols,PM,ammonia(NH3)and carbon dioxide(CO2)in different types of pigsties in winter and the correlation between harmful gases and particulate matter and microbial aerosols.The influencing factors of microbial aerosol and PM concentration provide scientific data for the management and control of pig house environmental production.1.Comparative analysis of concentration distribution of environmental particulate matter in different types of pigstiesThe TSI dust monitor,RC-4HC temperature-humidity meter and Testo 425 anemometer were used to monitor the concentration,temperature,humidity and wind speed of particles of different sizes(TSP,PM10,PM4,PM2.5 and PM1)in the three types of pigsties.The monitoring height was set at 0.8 m and 1.5 m from the ground.The particles and wind speed were monitored 7 times a day(3:00,7:00,9:00,11:00,15:00,17:00 and 22:00),the temperature and humidity are monitored automatically every 30 minutes for 3 consecutive days.The results showed that the temperature and humidity in the maternity house were the highest,followed by the nursery house,and the lowest in the pregnancy house;while the wind speed was opposite,the wind speed in the pregnancy house was the highest,followed by the nursery house,and the maternity house was the lowest;The mean mass concentrations of TSP,PM10,PM4,PM2.5 and PM1 in the pregnancy house were 1.734 mg/m3,0.760 mg/m3,0.313 mg/m3,0.270 mg/m3 and 0.249 mg/m3,respectively.The mean mass concentrations of TSP,PM10,PM4,PM2.5 and PM1 in the maternity house were 3.102 mg/m3,1.385 mg/m3,0.492 mg/m3,0.408 mg/m3 and 0.369 mg/m3,respectively.The mean mass concentrations of TSP,PM10,PM4,PM2.5 and PM1 in the nursery house were 1.284 mg/m3,0.572 mg/m3,0.271 mg/m3,0.245 mg/m3 and 0.230 mg/m3,respectively.There was no significant difference in PM10/TSP ratio between the three pigsties,while there was significant difference in PM2.5/TSP,PM2.5/PM10 and PM1/PM2.5 ratio.The PM concentration of different particle sizes in the pig house was significantly positively correlated with temperature and relative humidity.Conclusion:The PM pollution status is the most serious in the delivery house,followed by the pregnancy house,and the nursery house is the lightest;The TSP concentrations in the three types of pig houses exceed the national standard(1.2 mg/m3);The PM concentration changes in the pig house.The internal temperature is related to the change in relative humidity.2.Comparative analysis of microbial aerosols in different types of pigstiesMicrobiological aerosols in three types of pigsties were monitored and sampled by ZYK-6 six-stage sieve impingent microbiological sampler.The monitoring and sampling heights were set at 0.8 m from the ground and monitored 4 times a day(3:00,9:00,15:00 and 22:00)for 3 days.The results showed that the concentration of bacterial aerosol in the pregnancy house was 0.68×104～2.56×104 cfu/m3,the concentration of fungal aerosol was 0.17×103～0.87×103 cfu/m3,and the concentration of bacterial aerosol in maternity house was 0.41×104～2.21×104 cfu/m3,fungal aerosol concentration ranged from 0.44×103～2.48×103 cfu/m3;bacterial aerosol concentration in nursery house ranged from 2.12×103～6.85×103 cfu/m3,fungal aerosol concentration the range is 0.16×103～1.11×103 cfu/m3.The proportion of Gram-negative bacteria in the pigsties is 38.1%.However,harmful germ such as Staphylococcus aureus,Escherichia coli,Acinetobacter baumannii,A.flavus,Geotrichum candidum,Geotrichum candidum,Candida and Aspergillus oryzae were found in the pig house.The fungal aerosol in the pig house was significantly positively correlated with temperature and relative humidity,and the bacterial aerosol was significantly positively correlated with relative humidity.Conclusion:The comparison of the bacterial aerosol concentration in the three types of pigsties shows that the pregnancy house is the highest,followed by the delivery house,and the nursery house is the lowest,the concentrations did not exceed the national standard(4×104 cfu/m3).The microbial aerosol concentration changes and the house temperature and humidity changes are related.3.Distribution of harmful gas concentration in pig house and its correlation with particulate matter and microbial aerosol concentrationIn this test,the 1412 photoacoustic multi-point gas detector was used to monitor the dynamic changes of NH3,CO2,CO and NO concentrations in the pigsties.The monitoring height is set at 0.8 m and 1.5 m from the ground,monitored once every 2 hours,and continuously monitored for 3 days.The results showed that the concentration of NH3 in the pregnancy house,the maternity house and the nursery house ranged from 9.16 to 11.17 mg/m3,9.52 to 10.79 mg/m3 and 8.08 to 8.3 1 mg/m3,respectively;the CO2 concentration ranged from 2687 to 4107 mg/m3,3084～3792 mg/m3 and 1654～2233 mg/m3,respectively.;the average CO concentration was 7.74 mg/m3,7.95 mg/m3 and 9.31 mg/m3,respectively;the average NO concentration was 3.23 mg/m3,2.89 mg/m3 and 2.66 mg/m3,respectively.The concentrations of CO2 and NH3 were significantly positively correlated with the concentration of the different sizes PM.The CO concentration was significantly negatively correlated with the concentration of the different sizes PM.The NO concentration was not significantly correlated with the concentration of the different sizes PM.There was a significant positive correlation between bacterial aerosol concentration and CO2,CO,NO and NH3 concentrations.The correlation between fungal aerosol concentration and CO2,CO,NO and NH3 concentrations was not significant Conclusion:The level of NH3 is expressed as the maternity house>pregnancy house>nursery house>outside,and all of them do not exceed the national standard(20 mg/m3).The CO2 concentration level was expressed as the maternity house>pregnancy house>nursery house>outside,and the concentration of the three types of pig houses exceeded the national standard(1500 mg/m3).The concentration of CO2,NH3,CO and NO in the house will affect the concentration of PM with different particle sizes.The changes in CO2 and NH3 concentration will affect the concentration change of bacterial aerosol.In summary,the air quality of the three types of pig houses in the winter,the nursery is the best,the pregnancy is second,and the delivery is the worst.The concentrations of TSP and CO2 in the three types of pig houses exceeded the national standards.The concentration of particulate matter and microbial aerosol in the house was related to the temperature and humidity of the house and the concentration of harmful gases.