Ozone-initiated single-digit nanoparticle emissions from humans

Elevated exposure to nanoparticles has been linked to adverse health consequences, given their high specific surface area and deep penetration into human lungs. Similar to outdoors, nanoparticles in buildings are important precursors that form larger particles via coagulation and condensation. Indoor nanoparticles can originate both from outdoors, and from indoor emissions, such as cooking and personal care products.

Ozone-initiated chemistry also contributes to formation of indoor nanoparticles. Humans play an important role in indoor chemistry (Weschler, 2016). However, their impact on nanoparticle generation indoors is unknown. While we know that ozone reacts quickly with constituents of lipids on exposed skin (Weschler, 2016), nanoparticle generation caused by ozone-human chemistry remains unexplored.

Within the framework of the Indoor Chemical Human Emissions and Reactivity (ICHEAR) project (Bekö et al., submitted), we were the first to measure and report 1.18-4 nm nanoparticle emissions following ozone-initiated reactions occurring in the presence of humans. We also investigated the influence of clothing and age on nanoparticle emissions.

These preliminary results provide important new insights into ozone-human reactions associated with nanoparticle generation and ultimately exposures.