A Study on Elevated Fine Particles at a Crop-Agricultural Site in Gimje, South Korea: Impact of Local Sources on Event Days
JOONWOO KIM, Jiho Jang, Dahye Oh, Haebum Lee, Kihong Park,
Gwangju Institute of Science and Technology Abstract Number: 647
Working Group: Remote and Regional Atmospheric Aerosol
AbstractCrop-agricultural areas are sources of emissions such as carbonaceous species from crop residue burning and nitrogen species from fertilizer use. We measured gases and fine particles at a crop-agricultural site in Gimje, South Korea during the summer of 2021, to examine the influence of local sources on the formation of fine particle events under accumulation conditions. Two types of fine particle events were identified: crop residue burning and nitrate formation. During the fine particle event period with intensive open burning of crop residue, we observed drastically elevated levels of organic carbon (OC), elemental carbon (EC), black carbon (BC), potassium, chloride, and elements in fine particles. BC
biomass burning was higher than BC
fossil fuel combustion and EC. Water-soluble OC was higher than water-insoluble OC, with the strong enhancement of formaldehyde (HCHO), glyoxal (CHOCHO), nitrogen dioxide (NO
2), nitrous acid (HONO) and ozone (O
3), implying secondary organic aerosol formation. On other fine particle event days, nitrate dominated in fine particles with high aerosol water content (AWC). The particle fraction of total (gas + particle) nitrate was significantly increased depending on AWC, in addition to high levels of aerosol pH influenced by abundant ammonia (NH
3). Furthermore, total nitrate levels were not decreased although NO
2 levels were low. The variations of total nitrate were associated with HCHO variations, not local NO
2 variations, in the transition regime of O
3 formation. Our results show that crop residue burning and NH
3 emissions contributed to fine particle pollution at a crop-agricultual site.