Influence of haze pollution on water-soluble chemical species in PM2.5 and size-resolved particles at an urban site during fall
Geun-Hye Yu , Yan Zhang , Sung-Yong Cho , Seungshik Park
DOI:10.1016/j.jes.2016.10.018
Received August 25, 2016,Revised October 13, 2016, Accepted October 17, 2016, Available online December 30, 2016
Volume 29,2017,Pages 370-382
To investigate the influence of haze on the chemical composition and formation processes of ambient aerosol particles, PM2.5 and size-segregated aerosol particles were collected daily during fall atanurban siteofGwangju, Korea.Duringthe study period, the total concentration of secondary ionic species (SIS) contributed an average of 43.9% to the PM2.5 , whereas the contribution of SIS to the PM2.5 during the haze period was 62.3%. The NO3- and SO42- concentrations in PM2.5 during the haze period were highly elevated, being 13.4 and 5.0 times higher than those during non-haze period, respectively. The PM, NO3- , SO42- , oxalate,water-soluble organic carbon (WSOC), and humic-like substances (HULIS) had tri-modal size distributions peaks at 0.32, 1.0, and 5.2 μm during the non-haze and haze periods. However, during the non-haze period they exhibited dominant size distributions at the condensation mode peaking at 0.32 μm, while on October 21 when the heaviest haze event occurred, they had predominant droplet mode size distributions peaking at 1.00 μm. Moreover, strong correlations of WSOCandHULIS with SO42- , oxalate,and K+ at particle size sof<1.8 μmindicate thatsecondary processesand emissions from biomass burning could beresponsible for WSOC andHULISformations.Itwasfoundthatthefactorsaffectinghazeformationcouldbethelocal stable synoptic conditions, including the weak surface winds and high surface pressures, the long-range transportation of haze from eastern China and upwind regions of the Korean peninsula, as well as the locally emitted and produced aerosol particles.
