Organic compound concentrations of size-segregated PM10 during sugarcane burning and growing seasons at a rural and an urban site in Florida, USA

Abstract

Florida has the most land used to grow sugarcane crops in the United States. The preharvest sugarcane leaf burning elevates ambient particle matter (PM) concentrations in rural areas with dominant sugarcane agriculture (Belle Glade) and affects the air quality of coastal urban sites (Delray Beach). In this study, ambient particles segregated by size were analyzed to identify trace organic compounds from PM sources that may cause adverse health effects. The sampling campaign was conducted simultaneously at urban and rural sites, and revealed that the organic compound concentration of each particle size varies significantly between the sugarcane burning season (SBS) in January and sugarcane growing season (SGS) in May. The results indicated that PM3 contains at least 76% of the organic compound concentrations detected in the samples collected from both sites and during both seasons. The concentrations of trace organic compounds were higher in the SBS than in the SGS. Combustion-oriented hopanes, polycyclic aromatic hydrocarbons (PAHs), and oxygenated PAHs were mainly detected in PM0.49. The detection of elevated levoglucosan concentrations at the urban site indicates that fine particles generated from biomass burning traveled from the rural site to the urban site. Secondary organic compounds such as dicarboxylic acids, phytol, and 6,10,14-trimethyl-2-pentadecanone exhibited similar concentration patterns in the rural and urban sites during both seasons. In the SGS, PM10 concentrations at both sites were extremely similar; however, the organic compound levels were lower at the rural site than at the urban site in the SBS. This result should be investigated further by researchers investigating the health aspects of organic compound concentrations.