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Particulate matter (PM) from poultry production facilities may strongly affect the health of animals and workers in the houses, and PM emitted to the ambient air is an important pollution source to the surrounding areas. Aviary system is considered as a welfare friendly production system for laying hens. However, its air quality is typically worse as compared with conventional cage systems, because of the higher PM concentration of indoor air and other airborne contaminants. Furthermore, PM's physical property, which has a direct impact on the penetration depth into the lungs of the birds and humans, is largely unknown for the aviary system. Therefore, a systematic method was utilized to investigate the characteristics of particles in the aviary house with large cage aviary unit system (LCAU) in Beijing, China. For the field measurements, three measuring locations were selected with two inside and one outside the house with LCAU to continuously monitor PM concentrations and collect the samples for particle size distribution (PSD) analysis. Results showed that PM 2.5 , PM 10 , and total suspended particulate (TSP) concentrations averaged at 0.037 ± 0.025 mg/m 3 , 0.42 ± 0.10 mg/m 3 , and 1.92 ± 1.91 mg/m 3 , respectively. Particle concentrations increased from October to December due to less ventilation as the weather got colder, and were generally affected by stocking density, ventilation rate, birds' activities, and housing system. Meanwhile, indoor PM 2.5 concentration was easily impacted by the ambient air quality. Mass median diameter (MMD) and mass geometric standard deviation (MGSD) of the TSP during the measurement were 18.92 ± 7.08 μm and 3.11 ± 0.31, respectively. Count median diameter (CMD) and count geometric standard deviation (CGSD) were 1.94 ± 0.14 μm and 1.48 ± 0.08, respectively. Results indicated that the aviary system can attain a good indoor condition by suitable system design and environment control strategy. Implications : Indoor PM 2.5 concentration of the layer house can be significantly affected by ambient air quality when the air quality index (AQI) was larger than 100. PM 2.5 and PM 10 concentrations of the layer house with a LCAU system were comparable to the cage system. TSP concentration was higher, and PM size was larger than most of the cage system. System design, larger space volume, and higher ventilation rate were the main influence factors. Good indoor environment of the aviary system can be achieved through the reasonable design of the production system and appropriate environment control strategy.

Low-profile, cross-ventilated (LPCV) dairy barns represent a modern trend in farm buildings but are associated with notable air quality challenges. To evaluate the annual variations in the pollutants in an LPCV dairy barn, an Internet-of-Things (IoT)-based environmental monitoring system was installed to continuously measure the total suspended particle (TSP), particle with aerodynamic diameters of ≤2.5 μm (PM2.5), and NH3 concentrations year round at multiple points. Spatiotemporal distributions and main factors were analyzed. The results showed that the annual average concentrations of indoor TSP, PM2.5, and NH3 were 86.4, 28.5, and 875.0 μg/m3, respectively. Corresponding emission rates were 140.6, 28.5, and 3461.1 mg/(h·cow). TSP concentrations were significantly higher during winter and spring (p < 0.05) and were elevated during daily operational hours, particularly in feeding alleys and downwind areas. Emissions were significantly higher in winter and summer (p < 0.05). Indoor PM2.5 concentrations in winter exceeded China's standards for 24.9% of the time, which were 2.2 times higher than those in other seasons (p < 0.05), peaking in the morning hours. NH3 concentrations and emissions were consistently high throughout the year, with peak levels in manure and downwind areas. The building's structure, ventilations, and daily operations were key factors affecting air pollutant levels, which need to be considered when implementing mitigation measures. [ABSTRACT FROM AUTHOR]

A mixing fan and spraying system is commonly used to control the indoor environment of naturally ventilated dairy barns worldwide. However, its impact on particulate matter (PM) concentration and variation is still unclear due to the lack of year-round field data. To systematically characterize the PM dynamics under different environmental controls (namely, EC1: No Fans and No Spraying; EC2: Fans; EC3: Fans and Spraying), a year-round continuous monitoring of PM less than 2.5 μm in aerodynamic diameter (PM2.5) and total suspended particle (TSP) concentrations, as well as indoor environmental factors, was carried out inside a naturally ventilated dairy barn using an IoT-based sensor monitoring network. Results showed that the hourly mean TSP and PM2.5 concentrations were 94.7 μg m−3 and 49.8 μg m−3, respectively. EC2 had a higher TSP content (116.6 μg m−3) than EC1 (98.0 μg m−3) and EC3 (81.9 μg m−3). EC1 had the greatest PM2.5 concentration (57.1 μg m−3), followed by EC2 (48.3 μg m−3) and EC3 (44.7 μg m−3). EC1 showed clear TSP and PM2.5 fluctuations during the daily operations at 07:00 to 08:00 and 18:00 to 19:00, while irregular peaks in EC2 and a relatively steady diurnal variation in EC3 were found. Daily Tsp concentrations in the three ECs did not exceed 300 μg m−3. However, 17.8%, 11.5%, and 4.8% of the observed days in EC1, EC2, and EC3 had daily mean PM2.5 concentrations above the healthy threshold (75 μg m−3), mostly from 07:00 to 08:00 and 22:00–07:00. In conclusion, the mixing fan and spraying system had significant effects on PM concentration and variation, and more protection procedures should be taken for farm workers to prevent long-term health risk exposure, to EC1 in particular. [ABSTRACT FROM AUTHOR]

A year-round monitoring of Particulate Matter (PM) less than 2.5 μm in aerodynamic diameter (PM 2.5) and Total Suspended Particulate (TSP) from a conventional cage laying hen house was conducted to reveal their spatiotemporal variations of concentrations downwind of tunnel fans. The PM Emission Rate (ER) and the correlations between PM with meteorological parameters and ventilation rate were studied. Ten self-developed Particle Concentration Monitoring Units were distributed to multiple horizontal (2, 25, and 50 m) and vertical (2 and 5 m) locations for PM examination. Four PM 2.5 concentration categories were classified: good (0–35 μg m−3), moderate (35–75 μg m−3), unhealthy (75–150 μg m−3), and very unhealthy (150–350 μg m−3). Annual and monthly percentages of PM 2.5 and TSP sampling hours for each category were calculated. Significant temporal variations in ER were observed, with monthly average ER ranging from 0.05 to 0.86 mg d−1 hen−1 for PM 2.5 and 1.40–8.90 mg d−1 hen−1 for TSP. Approximately 10–40% of PM 2.5 sampling hours exceeded 75 μg m−3, while no TSP concentration was higher than the recommended threshold. The monthly percentage for the "very unhealthy" PM 2.5 category was higher in winter, whereas the highest monthly percentage for the 800–1,200 μg m−3 TSP category was found in summer. Higher PM 2.5 concentrations were prone to be observed at further sampling points, while higher TSP concentrations were mostly detected near the fans or on both sides of the sampling area. PM 2.5 and TSP were positively correlated with ambient temperature and ventilation rate, while negatively correlated with relative humidity. • The emission rate of particulate matter in laying hen house had seasonal variations. • PM 2.5 concentrations at further locations downwind of fans were prone to be higher. • TSP concentrations near the fans were prone to be higher. • Hazardous PM 2.5 concentrations were more frequently observed in winter. • PM 2.5 and TSP were correlated with meteorological parameters and ventilation rate. [ABSTRACT FROM AUTHOR]

Inhaling particulate matter (PM) poses a potential risk on the health of workers and chickens for long-term exposure to highly contaminated air in buildings, while the exceedance of PM concentration limit is still unclear for lack of direct measurement data covering the annual production cycle of laying hen farms. This research investigated the indoor PM characteristics in three typical laying hen building systems of natural mating colony cage (NM), conventional cage (CC), and aviary (AV) in China based on a year-round field measurement of PM concentrations using the Internet of Things. Results suggested that the average PM 2.5 and total suspended particulate (TSP) concentrations in NM were 0.042 ± 0.016 and 0.345 ± 0.143 mg m−3, respectively. The corresponding results were 0.048 ± 0.021 and 0.305 ± 0.171 mg m−3 in CC, 0.025 ± 0.012 and 0.786 ± 0.875 mg m−3 in AV, respectively. During the working period, PM 2.5 concentrations in 3% and 6.5% of the monitored days exceeded the threshold of 0.075 mg m−3 in NM and CC, meanwhile about 11% of the daily mean TSP concentrations in AV were higher than the recommended limit of 2.4 mg m−3. Generally, the average PM concentrations in three building systems with appropriate system designs and management were maintained at relatively low levels, which were beneficial to the health and production performance of laying hens. Occasional exceedance of PM concentration thresholds may chronically impair the respiratory health of the workers, and preventive measures should be therefore taken while working in laying hen houses. • An IoT system was developed to long-term monitor PM concentration in poultry houses. • The PM 2.5 and TSP concentrations of laying hen building systems in China were low. • Occasional exceedances of PM concentration limit were found during working period. • The PM exposure risk on the respiratory health existed but lower than other systems. [ABSTRACT FROM AUTHOR]