10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Sources and Transformations to Atmospheric Aerosols in Winter: A Carbon and Nitrogen Isotopic Study in Beijing
QIAN YU, Mo Xue, Di Wu, Lei Duan, Jingkun Jiang, Shuxiao Wang, Tsinghua University
Abstract Number: 199 Working Group: Source Apportionment
Abstract Stable carbon and nitrogen isotopic compositions can provide complementary information about sources and transformations of atmospheric aerosol and have long been conducted in several sites in developed countries. However, little is known in China and no extensive studies have been focused on stable carbon and nitrogen simultaneously. Here, we report 13C and 15N natural abundance (δ13C, δ15N) for PM1.0 and PM2.5 collected in Beijing during November to December 2017, together with nitrate (NO3-), ammonium (NH4+), and organic matter contents from two online aerosol chemical composition monitors using liquid chromatography and mass spectrometry, respectively. The objective was to test whether δ13C and δ15N can be used to reveal sources and transformations of atmospheric aerosol. We found that δ13C in PM2.5 and PM1.0 ranged from -26.9‰ to -22.9‰ (ave. 24.5 ± 0.7‰) and -28.3‰ to -25.7‰ (ave. 27.4 ± 0.9 ‰), respectively. It indicates that coal combustion and vehicle emission (or second formation) contribute significantly to organic composition of PM2.5 and PM1.0 in Beijing. δ15N of PM2.5 had a wide range (1.64‰ -15.2‰, ave. 10.2 ± 3.1‰) and had distinct values during the clean day ( 1.64‰ -7.54‰) and polluted period (10.2‰-15.2‰). δ15N were not significantly related to aerosol mass concentrations or the NO3- and NH4+ contents, but showed positively correlation with the ratio of NO3--N/( NO3--N+NH4+-N). It suggests that primary emission from coal combustion contributes to atmospheric aerosol in the clean day, but second formation from photochemical processing of NOx was the major source during the polluted period. This study, explicitly recognizing the different sources and transformations of atmospheric aerosol in different size range and during different episodes, established stable isotope method for regional source apportionment of ambient particulate matter.