Semi-volatile Organic Contaminants in the Urban Atmosphere: Spatial and Seasonal Distributions and Implications for Contaminant Transport

• Main Author: Melymuk, Lisa
• Other Authors: Diamond, Miriam L.
• Language: en_ca
• Published: 2012
• Subjects: environmental science; atmospheric pollution; urban areas; 0775
• Online Access: http://hdl.handle.net/1807/32771

Spatial and temporal patterns of semi-volatile organic contaminant (SVOC) concentrations in air and precipitation were investigated at the urban scale in order to improve our understanding of emission sources and factors affecting intra-urban variability. Toronto, Canada was used as a case study. Advances were made in two methods used to examine intra-urban variability, namely passive air sampling and land use regression analysis. The study showed that these methods are useful for assessing local-scale variability, and that passive air sampler concentrations are most reliable when using homologue-specific sampling rates obtained from a co-located low volume sampler. The results of the spatially and temporally distributed sampling demonstrated that the highest atmospheric concentrations of SVOCs were associated with the highest density regions of the urban area. Temporal patterns of elevated concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs) in warm seasons were consistent with temperature-related emission processes such as volatilization and/or ventilation of indoor air. Spatial patterns in air concentrations were influenced by local sources on a scale of <5 km and were explained by factors related to human population activities such as building volume (PBDEs), population density (polycyclic musks, or PCMs), residential, commercial and transportation infrastructure (PAHs), and chemical inventory (PCBs). Industrial activities were not important factors. The link between elevated environmental concentrations and the in-use stock of banned chemicals, such as PCBs and PBDEs, suggest that efforts to control emissions and reduce environmental concentrations must address the removal of current use products, in addition to the bans on new uses of the SVOCs.