Evaluation of the ammonia emission sensitivity of secondary inorganic aerosol concentrations measured by the national reference method. (1st February 2022)

• Record Type: Journal Article
• Authors: Lim, JeongHoon; Park, HyeonYeong; Cho, SeogYeon
• Is Part Of: Atmospheric environment. Volume 270(2022)
• Publication Date: 2022-02-01
• Subjects: PM2.5 -- Emission sensitivity -- Ammonia emission -- Teflon-membrane filter -- Nitrate evaporation loss; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2021.118903
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: A national reference method for fine particulate matter mass measurement usually specifies Teflon-membrane filter for the collection of ambient particles. Ammonium nitrate, one of the major components of fine particulate matter, is semi-volatile and susceptible to evaporation loss during and after field sampling by Teflon-membrane filter. The goal of this study is to evaluate the ammonia emission sensitivity of secondary inorganic aerosol (SIA) concentrations measured by the national reference method. The evaporation loss of particulate ammonium nitrate during and after field sampling was included in the analysis to cover a wide range of emission scenarios and meteorological conditions. The global to mesoscale air quality forecast and analysis system was used to predict the PM2.5 concentrations and chemical compositions. The predicted relative humidity and temperature were used to calculate the amount of ammonium nitrate evaporation loss from the thermodynamic equilibrium model. Except for the cool months, the particulate ammonium nitrate evaporation loss significantly decreases the ammonium nitrate contents in the SIA and subsequently degraded the effectiveness of ammonia emission control over the SIA. The SIA concentration decrease achieved by a 30% reduction of ammonia emission is lessened by 27–33% in the spring, 49–79% in the summer, 21–41% in the fall when the ammonium nitrate evaporation loss is included. We also proposed the normalized ammonia emission sensitivity of ammonium nitrate concentrations (γ(NH4 NO3 )) as a measure of the effectiveness of ammonia control and derived a mathematical relationship between γ(NH4 NO3 ) and ammonia reduction rates in ammonia-rich conditions. Highlights: NH4 NO3 evaporation loss is estimated from the chemical transport model outputs. NH4 NO3 formation is limited not by NH3 but by HNO3 in the winter in Korea. NH4 NO3 evaporation loss degrades the NH3 emission control efficiency over the SIA. Normalized NH3 emission sensitivity measures the effectiveness of NH3 control. NH3 emission sensitivity formula covering various emission scenarios was derived.