Temporal Variations and Source Apportionment of Biomass Burning and Biogenic Organic Aerosols in the Pearl River Delta: Effects of the Monsoon, Plant Phenology, and Anthropogenic Activities

Abstract

Biomass burning (BB) and biogenic emissions significantly influence the chemical compositions of organic aerosols (OAs). In this study, aerosol samples collected throughout the year from a regional receptor site in the Pearl River Delta (PRD) were analyzed for BB tracers, primary biological aerosol particle (PBAP) tracers, and biogenic secondary organic aerosol tracers. The BB aerosol concentrations were highest from November to January, and this was mainly attributed to domestic biomass burning in southern China. Biomass burning emissions in Southeast Asia affected the PRD through long-range transport between May and August. Two primary sugar concentration peaks, one in September and October and the other in March, may reflect regional plant phenology, and the constant concentrations for most of the year indicated regional PBAP background emissions. Concentration and correlation analyses indicated that the use of arabitol, erythritol, and inositol as PBAP tracers may not be appropriate because of strong interference by intensive BB emissions. Positive matrix factorization source apportionment showed that plant debris and fungal spores (46%) were the dominant contributors to BB and biogenic organic aerosols (BOAs) during the marine monsoon, but that BB (28%) was the most important contributor during the continental monsoon. The positive matrix factorization results agreed well with the molecular-level radiocarbon-based source apportionment results. Our work indicates that geographic and anthropogenic factors, including the monsoon, plant phenology, and anthropogenic activities, combine to control the chemical compositions of BB and BOAs in the PRD.