南京持续雾霾天气中亚微米细颗粒物化学组分及光学性质

Abstract

A lasting haze pollution event occurred in the Central and East China in January 2013. In this study, Aerodyne Aerosol Chemical Speciation Monitor (ACSM), Photoacoustic Extinctiometer (PAX), and Aethalometer were deployed for real-time and lasting monitoring of non-refractory submicron aerosol (NR-PM1) components (i.e. organics, sulfate, nitrate, ammonium, and chloride), atmospheric aerosol extinction properties, and black carbon (BC) in Nanjing, respectively. During the measuring period, the contribution of PM1 (NR-PM1+BC) species, i.e., organics, nitrate, sulfate, ammonium, chloride, and BC were 32.3%, 26.0%, 17.9%, 13.2%, 2.8%, and 7.8%, respectively. Positive matrix factorization (PMF) analysis indicates that hydrocarbon-like (HOA), semi-volatile oxygenated organic aerosol (SV-OOA), low-volatile oxygenated organic aerosol (LV-OOA) were the major sources for PM1. HOA, SV-OOA, and LV-OOA on average accounted for 27.4%, 32.2%, and 40.4% of organic aerosol, respectively, which means that PM1 consisted mostly of the secondary species. Because of local cooking and traffic emissions, HOA loading dynamically increased at the nighttime, which resulted in a significant variation of organics. Generally, the mass concentrations, the mass fractions of secondary components (i.e. nitrate, sulfate, SV-OOA, and LV-OOA), as well as aerosol signal scattering albedo increased with increasing relative humidity (RH), respectively, implying that the increase in RH was beneficial to the continual formation of secondary aerosol. Furthermore, atmospheric visibility decreased with the increasing of RH and secondary species contents, indicating that there is a synergistic effect between the RH and the secondary species of PM1 on the atmospheric visibility during the haze period.