Abstract for presentation at 14th IUAPPA World Congress

Exposure to ambient air pollution is recognised to contribute to increased incidence, and mortality, arising from lung cancer, cardiovascular diseases, and respiratory illnesses. Toxicological studies can help to identify which components of particulate air pollution are of health relevance for a given city. A suite of assays was used to assess the toxicity of ambient air particles from Christchurch (PM₁₀, PM_2.5) and Auckland (PM₁₀), New Zealand. Specifically, the carcinogenic potential (mutagenicity, dioxin-like activity), inflammatory potential (TNF-a, IL-6 release from an alveolar macrophage (RAW 264.7) cell line) and cytotoxicity of organic extracts and water-soluble extracts of the samples was examined. Particulate concentrations (24-hr average, Hi-vol sampling) ranged from 4.7 to 122 ug/m³ in Christchurch, with the highest concentrations recorded over May-August when wood-burners for home heating are widely in use. In contrast, particulate concentrations in Auckland ranged from 10 to 24 ug/m³ with the highest concentrations being recorded during March.
Dioxin-like activity was highest in Christchurch air samples ranging from <1 pgTCDD/m³ in Feb/March to 228 pgTCDD/m³ in winter, with activity correlated with particulate concentration. Lower dioxin-like activity (<1 to 2.2 pgTCDD/m³) was observed in Auckland samples. Christchurch particulates exhibited the highest dioxin-like activity, expressed as activity per mg particulates. The organic fraction showed no significant inflammatory potential, while exposure to water soluble extracts induced production of TNF-a. Particulate samples from Auckland induced a higher inflammatory response than those from Christchurch. Arsenic, zinc, iron, copper (in decreasing order of abundance) were found highest concentrations in the water soluble extracts.