Ammonia data and its related species measured and simulated in the megacity of Beijing during November to December of 2016

To further understand the effects of NH3 on the formation of haze pollution in Beijing, ambient NH3 and related species were measured and simulated at high resolutions during the wintertime Air Pollution and Human Health-Beijing (APHH-Beijing) campaign in 2016. The excess NHx was calculated upon the equilibrium system of SO42--NO3--NH4+-water during this campaign.

We applied ISORROPIA II model to calculate the aerosol acidity, aerosol water content (AWC) as well as its sensitivity to the SOx(SO2+SO42-),NOx(NO2+NO3-), NHx(NH3+NH4+) inputs. We also run the 3 D model NAQPMS to quantify the effects of NH3 to the heavy pollution in NCP. We found the Increased formation of NH4NO3 under excess NHx, especially during the nighttime, may trigger the decreasing of aerosol deliquescence relative humidity (DRH) even down to less than 50% and hence lead to hygroscopic growth even under RH conditions lower than 50% and the wet aerosol particles become better medium for rapid heterogeneous reactions.