Measurement of Ozone Emission and Particle Removal Rates from Portable Air Purifiers

Portable air purifiers are popular consumer items, especially in areas with poor air quality. Unfortunately, most users of these air purifiers have minimal understanding of the factors affecting their efficiency in typical indoor settings. Emission of the air pollutant ozone (O3) by certain air purifiers is of particular concern. In an effort to better educate the public, we created a laboratory protocol aimed at characterizing the performance of air purifiers designed for rooms, refrigerators, cars, and personal use. The laboratory protocol relies on standard aerosol particle counting techniques to measure the clean air delivery rate (CADR) and UV photometry to quantify the ozone emission rate for air purifiers. The students analyze their measurements and discuss the implications for indoor air quality and ozone chemistry. The laboratory is suitable for students with a wide range of education and laboratory experience.