Partitioning of NH3-NH4+ in the Southeastern U.S.

The formation of inorganic fine particulate matter (i.e., iPM2.5) is controlled by the thermodynamic equilibrium partitioning NH3-NH4+. To develop effective control strategies PM2.5, we aim to understand impacts changes in different precursor gases on iPM2.5 concentrations and NH3-NH4+ southeastern U.S., responses four seasons were investigated using field measurements iPM2.5, gases, meteorological conditions. ISORROPIA II model was used examine effects total ammonia (gas + aerosol), sulfuric acid (aerosol), nitric aerosol) results indicate that reduction H2SO4 more than HNO3 NH3 reduce especially under NH3-rich condition. may change towards gas-phase also lead an increase NO3? conditions, which does not necessarily full neutralization acidic (pH < 7). Thus, future necessitate coordinated both U.S. It found response sensitive summer winter due dominance SO42? salts high temperature summer. emissions from Animal Feeding Operations (AFOs) at agricultural rural site (YRK) had great Multiple Linear Regression (MLR) revealed a strong positive correlation between cation-NH4+ anions-SO42? NO3?. This research provides insight into mechanism for advancement PM2.5 regulation