Characterization of trace elements and ions in PM₁₀ and PM_2.5 emitted from animal confinement buildings

Chemical characterization of PM emanating from animal confinement buildings can provide essential information for receptor modeling-based PM source apportionment as well as health effects assessment. In this study, PM₁₀ and PM_2.5 samples were collected from twelve swine (farrowing, gestation, weaning, and finishing) and six poultry (layer hen and tom turkey) confinement buildings in the U.S. Midwest and their inorganic composition, in terms of trace elements and ions, was investigated. A total of 23 species were identified and quantified, including Al, B, Ba, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, S, Si, Sr, Ti, Zn, Cl^-, NO₃^-, SO₄^2- and NH₄⁺. The total mass fraction of identified species was typically less than 16%. NH₄⁺ was detected in low contents (<1% wt.) in collected PM samples, suggesting that the majority of NH₃-N emissions were in gas form and the formation of NH₄⁺-containing secondary aerosols is insignificant in animal confinement buildings. Several multivariate analysis tools prevalent in ecology research were implemented for examining variability in PM inorganic compositions. Results showed that PM inorganic composition varied significantly with animal building type. Seasons had no significant effect on PM₁₀ and a significant but weak effect on PM_2.5 inorganic compositions. Compared to PM₁₀ samples, PM_2.5 samples from different types of animal confinement buildings were more similar in inorganic composition.