Assessment of particulate matter, aerosol and gaseous contaminant broiler facility
This study characterized the generation of gaseous pollutants, including acid gases (hydrochloric acid, nitric acid, nitrous acid, and sulfur dioxide), ammonia and methane, as well as size fractionated particulate matter and dominant aerosol species associated with inorganic aerosol formation (ammonium, chloride, nitrate, sodium, and sulfate) at a commercial broiler chicken facility. The methodology selected to quantify emissions of acid gases, ammonia and the aerosol species involved collecting them with annular denuders and a filter pack and subsequently analyzing the extracted samples with an ion chromatography system. Ionic aerosol species representative of aerosol formation from gaseous ammonia combining with acid gases contributed somewhat to the particulate matter mass in their size fractionation (<= 2.5 microns, PM2.5). There were, however, significant contributions from chloride aerosols, believed to be associated with sodium ions and the moisture on pre-existing particulates. Including these aerosols, the mean mass contribution of the dominant five ionic species (listed previously) to PM2.5 mass was 41.3 ± 16.6 %. These aerosols originated from the litter, which contained high levels of each ionic species accumulated from the undigested feed and water in the birds' excretions. This research also demonstrated that pollutants have common sources/release mechanisms and it was, therefore, reasonable to assume that their emissions followed similar trends. It was discovered that pollutant emissions share a mutual behaviour with house environmental parameters, such as indoor temperature. This led to the generation of emission correlations that contained only house environment variables measured by the control system prior to the measurement campaign. The correlations successfully captured the daily and seasonal variability in emissions for each pollutant when applied to both dependent and independent datasets. Using the measured emissions and the correlations to fill in data gaps, the mean PM10 and PM2.5 emission factors were computed as 5.9 and 4.6 g day-1 AU-1 and 1.4 and 0.8 g day -1 AU-1 (Animal Unit = 500 kg live mass), respectively, for six and five week production cycles, respectively. The ammonia and methane emissions were estimated at 120.8 and 197.0 g day -1 AU-1, respectively, for a five week production cycle.