Peat fires and air quality: volatile organic compounds and particulates.
Computing, Health and Science
Natural Sciences, Centre for Ecosystem Management
There are numerous localized peat deposits on the Swan Coastal Plain, an urban and rural bioregion otherwise dominated by wetland ecosystems in southwestern Australia. Hydrological change is significant in the bioregion: urban development encroaches on wetlands, groundwater extraction provides the city population with most of its water, and rainfall declines will not recharge aquifers in the future. The wetland processes which contribute to the formation of these peat deposits have therefore changed and are becoming vulnerable to fire events with residents increasingly exposed to peat smoke. There is an imperative to characterise this peat smoke to determine if exposures are harmful or toxic, and opportunities to do so in this setting arise due to the absence of bushfire smoke which has confounded other international studies. We have measured volatile organic compounds (VOCs) and particulate concentrations from an opportunistic assessment of two peat fires. SUMMA canister grab samples and a portable GCMS were used to determine the VOCs with high 1 h benzene concentrations of 16 and 30 ppm v/v. PM10 and PM2.5 particulate data were collected using an Osiris continuous analyser with 24 h concentrations recorded at varying time periods (within a 5 months timeframe) ranging from 1 h maximums of between 23–37 lgm_3 for PM10 and 50.5–106 lgm_3 for PM2.5. While the 24 h averages were generally below national air quality standards, elevated 1 h concentrations were observed on numerous occasions and on most days. Given the proximity of residential development to many peat deposits, a drying climate and the increased risk of arson in peri-urban environments, the health impacts of exposure to peat smoke need to be determined and if necessary measures developed to prevent exposure (which would include maintaining wetland sediment integrity so as to reduce its vulnerability to fire).