Exploration on the source of NH4+ in condensable particulate matter

Abstract

Condensed particulate matter (CPM) is a type of pollutant that has attracted much attention due to its small emission size and complex composition. CPM consists of both inorganic and organic components, and exploring their sources is beneficial for understanding the emission characteristic and the control strategy of CPM. Among the inorganic components, NH4+ is one of the dominant cations contained in previous work's CPM samples, whose sources are still unclear. In this work, experiments were performed in two scales to investigate the potential sources of NH4+ contained in the CPM samples, one was based on a simulated flue gas experimental system, and the other was based on a real flue gas one. In both cases, ammonium-containing substances, gases or solutions with known concentrations, were intentionally added into the flue gas, and the changes of NH4+ and other concerned components in the CPM samples collected from the flue gas were compared to judge the source of it. The results showed that NH3 in the flue gas was the dominant source of NH4+ in the CPM samples. The presence of NH3, SO2, chlorine containing substances, ammonium sulfate and ammonium sulfite in the flue gas can affect the contents of both NH4+ and SO42− in the CPM samples.