Assessments and Application of Low-Cost Sensors to Study Indoor Air Quality in Layer Facilities

Afroz, Rowshon and Guo, Xinyang and Cheng, Chu-Wen and Omar, Sohaib and Carney, V. L. and Zuidhof, Martin J. and Zhao, Ran, Assessments and Application of Low-Cost Sensors to Study Indoor Air Quality in Layer Facilities.

About

Intensive poultry farming deals with flocks of several thousand birds gathered in one or several buildings, and it can be a significant source of air contamination. Thus, worries regarding the emissions of contaminants such as aerosolized particles or dust, and various gases from intensive poultry facilities are growing, especially concerning their impact on the environment and health. Dust can originate from various sources, including floor bedding, feed, feathers, excreta, dander, bird’s skin, and microorganisms. Given that, monitoring and source apportionment of dust are crucial for creating appropriate regulations that protect the health of birds and producers. Therefore, it is essential to collect real-time, spatiotemporally-resolved data for a complete understanding of PM characterization and to accurately assess exposure for both humans and animals. Unfortunately, air monitoring instruments available on the market are generally expensive (costs >$20,000 CAD each) and unable to provide sufficient coverage of air quality in dusty barn environments. In this regard, this study was conducted to implement and assess the field performance of a compact, custom built IoT low-cost air quality sensor (LCS -$180 CAD) network in an indoor table egg farm in Canada. The sensor-enabled real-time monitoring of PM2.5, PM10, and CO2 concentrations, RH, and temperature. The work also aimed to characterize factors that affect these parameters in the farm. The findings of this study will both showcase a novel technique and provide scientific insights into environmental conditions in commercial poultry facilities.

Approach

The LCS performance was assessed in the Poultry Research Centre (PRC) farm with 70 ± 7 birds housed in floor pens. At this stage, three LCS were set up to assess their performance from November 2021 to September 2022. Then, we monitored indoor air quality (IAQ) in a commercial layer farm from November 2022 to April 2023, where six LCS were deployed. This freerun, organic egg farm had a capacity of approximately 8,000 laying hens in a single barn. A sensor was installed in the preparation room of the farm to observe the correlation and concentration of PM levels because workers do not wear personal protection equipment (PPE) in there as they do inside the barn. Inside the barn, the sensors were deployed at different heights (0.6 and 2.7 meters) and locations, including along the front of the cage and on the wall. The LCS were deployed continuously at the PRC and commercial farm. To ensure their accuracy and performance, a reference instrument was colocated with the LCS and checked during every farm visit made by the research team.

Analysis of Results

Our research found that the concentrations of both PM10 and PM2.5 followed a diurnal pattern. Both PM10 and PM2.5 concentrations were low at nighttime (when the light was off) but spiked during the daytime. This suggests that PM emissions were significantly impacted by the activity level of chickens. The mean hourly average of PM10 and PM2.5 concentrations for sensors during daytime were 5.5 × 104 ± 2.2 × 104 and 6.3 × 103 ± 2.3 × 103 µg/m3, respectively, while concentrations during nighttime were 4.9 × 103 ± 2.4 × 103 and 750 ± 80 µg/m3 for PM10 and PM2.5, respectively. Higher PM levels during the daytime, unfortunately, mean that farm workers’ respiratory health is at considerable risk. Additionally, the study found a positive correlation between PM2.5 and PM10 levels inside the barn and in the preparation room, indicating that the dust infiltrated from the barn to its outside through openings, elevating the PM levels. The study suggests that both PM10 (91 ± 103 µg/m3) and PM2.5 concentrations (33 ± 15 µg/m3) may exceed recommended daily exposure limits, underscoring the importance of considering the health impacts over time. Given that producers work there without wearing PPE, the concentration we recorded can be a health concern even though the preparation room concentrations were much lower than the barn concentration.

Application

This study demonstrated the development and application of low-cost air quality sensors (LCS) in poultry facilities. Our sensors ($180 CAD ea.) had the capacity to measure PM2.5, PM10, CO2, temperature, and RH, which are all considered key IAQ parameters. Our study reveals that the laying house had elevated levels of PM and CO2. A strong correlation was also found between the indoor concentration of PM, CO2, and relative humidity. The concentration levels and trends of both pollutants were influenced by factors such as chicken activity, light regime, ventilation rate, and outdoor temperature. In addition, the study also observed the impact of housing pollutants on areas where producers work regularly but not with PPE. Overall, our results suggest that the LCS could be a valuable tool for monitoring IAQ in poultry facilities.

Abstract

Indoor poultry facilities often experience poor air quality due to intensive farming and restricted ventilation. Monitoring the air quality in these barns is crucial considering the health of both the birds and producers. Advancements in sensor technologies have led to the development of low-cost sensors (LCS) that can continuously monitor air pollutants. Even though most poultry facilities in Canada are indoors due to harsh winter weather conditions, there is a lack of indoor air quality (IAQ) studies. This study aimed to evaluate the field performance of the LCS network in a table egg farm in Canada, where the sensors were designed specifically for operating in dusty poultry facilities continuously. The LCS monitored IQA parameters such as particulate matter (PM), carbon dioxide (CO2), relative humidity, and temperature in real-time. By implementing a correction factor, the sensor data resulted in an agreement range of 80 ± 20% with a reference instrument. The study observed that PM concentration exceeded several thousand µg/m3, with PM10 at 5.5×104 ± 2.2×104 and PM2.5 at 6.3×103 ± 2.3×103, which was found to be most affected by the chicken activity and light regime. The IAQ parameters also exhibited a complex intercorrelation with each other, as well as the outdoor temperature and the building ventilation rate. Sensors were able to make observations that were found only with research-grade instruments in previous studies. Overall, the study showcases the potential of the LCS network as an affordable solution for environmental monitoring in poultry facilities.

KEYWORDS: Low-cost sensors, sustainable food production, layer facilities, indoor air quality, particulate matter, dust