Oxidative Potential of Indoor Particulate Matter Collected During Campaigns in the UK, Slovenia, and Sweden

The health effects of particulate matter (PM) are well-documented, with long-term exposure to elevated concentrations of respirable PM linked to increased risks of respiratory conditions such as allergic reactions, lung inflammation, and asthma. A key contributor to these health effects is the oxidative stress induced by PM, stemming from heavy metals and the generation of reactive oxygen species (ROS).

In this study, we measured the oxidative potential (OP) of respirable dust and inhalable PM collected from households in Slovenia, Sweden, and the UK as part of the international INQUIRE project on air quality. Samples were collected using active samplers, and OP was assessed using a simulated epithelial lung fluid (SELF) model, following established protocols. Quantitative mass spectrometry was employed to determine the depletion rates of key lung antioxidants, including glutathione, cysteine, and ascorbic acid, alongside the accumulation of glutathione dimer.

Our results revealed statistically significant higher antioxidant depletion rates in experiments with PM compared to control samples. To elucidate the underlying mechanisms, we measured the concentrations of soluble heavy metals and analyzed water-soluble organic matter (WSOM) from both coarse and fine PM fractions using high-resolution mass spectrometry. Correlations between the relative abundance of organic constituents and antioxidant depletion rates highlighted the role of specific organic compounds in driving oxidative potential.

These findings underscore the need for targeted intervention strategies to mitigate the health risks associated with PM-induced oxidative stress in indoor environments.