Oxidative potential of ambient particulate matter from community sites in Alberta's oil sands region

Air pollution is a major environmental health risk and it has been associated with various diseases and mortality worldwide. The inhalation of fine particulate matter (PM) is an important cause of health effects from air pollution with one of underlaying mechanisms involving the induction of oxidative stress in the body. Oil sands mining is a major economic sector and a notable source of air pollution in northern Alberta, Canada. Despite this, studies investigating the potential health impacts associated with exposure to air pollutants in the region are rare. For the first time in this work, using an acellular ^•OH assay, we studied the oxidative potential (OP) of fine (<2.5 μm diameter) and coarse (2.5-10 μm diameter) PM from four community sites in the vicinity of oil sands production facilities. OP_OH was found to be dominated by fine PM, which on average accounted for 70 % reactivity of the studied PM size range. The highest OP_OH was found at the most populated sites located south of the open pit mines and with mixed emission sources, suggesting a cumulative effect of oil sands and non-oil sands sources. Nevertheless, OP_OH was relatively small compared to values reported for urban sites influenced by traffic and industrial emissions in Canada. OP_OH variation could not be linked with a statistical significance to changes in the concentrations of PM, trace metals, and secondary inorganic salts but, for a small set of samples, OP_OH was associated with organic carbon and potassium, which suggests the influence of reactive organic species from biomass combustion. A larger sample size will be needed in order to examine more closely the links between various OP metrics and the aerosol composition and sources in the region. This work provides a proof of concept to support future studies aimed at assessing potential health impacts associated with exposure to air pollutants in the oil sands region.