New insights into concentrations, sources and transformations of NH3, NOx, SO2 and PM at a commercial manure-belt layer house.

Pollutant gases and particulate matters (PM) from livestock facilities can affect the health of animals and farm workers and lead to great social environmental risks. This paper presents a comprehensive study on the characteristics of ammonia (NH 3), nitrogen oxides (NO x), sulfur dioxide (SO 2) and PM (including PM 2.5 and PM 10) in a 100,000-bird manure-belt layer house in suburb Beijing for three typical seasons of summer, autumn and winter. Indoor air was sampled at an exhaust fan of the mechanically ventilated commercial house. The monitored indoor concentrations of NH 3 , NO x , SO 2 , PM 2.5 and PM 10 were 3.7–5.0 mg m⁻³, 17–58 μg m⁻³, 0–11 μg m⁻³, 100–149 μg m⁻³ and 354–828 μg m⁻³, respectively. The indoor NH 3 concentrations were largely influenced by the manure removal frequency. The NO x and SO 2 were mainly sourced from the ambient air, and the NO x was also partly sourced from manure decomposition in summer. The indoor PM 2.5 and PM 10 were largely sourced from the ambient air and the indoor manure, respectively. The abundant indoor NH 3 caused significantly higher NH 4 ⁺ concentration in the indoor PM 10 (7.98 ± 9.04 μg m⁻³) than that in the ambient PM 10 (3.48 ± 3.52 μg m⁻³). Secondary inorganic ions (SO 4 ²⁻, NO 3 ⁻ and NH 4 ⁺) totally contributed 5.7% and 14.6% to the indoor and ambient PM 2.5 , respectively; they contributed 2.8% and 8.9% to the indoor and ambient PM 10 , respectively. Organic carbon was the main component of the PM and accounted for 26.6% and 41.5% of the indoor PM 2.5 and PM 10 , respectively. Heavy metal elements (Zn, Cu and Cr) were likely transported from feed to manure and finally accumulated in the PM. Given the high emission potential, the air pollutants from animal production suggested potential risks for human health. Image 1 • Indoor NO x , SO 2 and PM 2.5 were mainly sourced from the ambient air. • Indoor NO x was also partly sourced from manure decomposition in summer. • Indoor PM 10 had higher NH 4 ⁺ concentration than ambient PM 10 (7.98 vs. 3.48 μg m⁻³). • Secondary inorganic ions contributed 5.7% (14.6%) to the indoor (ambient) PM 2.5. • Zn, Cu, Cr likely transported from feed to manure and finally accumulated in PM. Sources for aerial pollutants of NH3, NOx, SO2, PM2.5 and PM10 in layer house were identified. The characteristics of indoor PM components including heavy metal elements and secondary inorganic ions were revealed. [ABSTRACT FROM AUTHOR]