Formation, Morphology and Hygroscopic Growth of Indoor Aerosols by Oxidation of Household Products

In this work, we have characterized the heterogeneous formation of particles from typical household materials. Gas phase VOCs are known to react with oxidants such as ozone to form new particles. Common sources of gas phase VOCs include pine-based cleaners, plug-in air fresheners, and “green” paints. This project specifically looked into the particles given off by a common orange-scented dish soap, scented antibacterial cleaning wipes, and a common aerosol-can air freshener.
A smog-chamber was used to characterize the contribution of different household objects to particle formation. Our smog chamber consists of a one cubic meter Teflon bag. The rate, number and size concentration, and other features of the particle formation were monitored by a scanning mobility particle sizer (SMPS). Additionally, the particles were collected and subsequently viewed on the scanning electron microscope (SEM) to see the particles’ morphology. We also used a Humidity Tandem Differential Mobility Analyzer (H-TDMA), in which produced particles were subject to elevated humidities, such as those found in human airways, and changes in physical size of the particles were monitored. The tendency of organic particles to grow in humid conditions depends on the chemical composition of the particles and thus needs to be measured directly. The final physical size of the particles determines where in the human airway the particles are likely to be collected and has significant implications in determining the associated health effects.
Results of this work, including particle growth, size distributions, morphology, and hygroscopic properties will be presented and compared with similar data reported for past experiments on other household products.