Assessment of PM2.5 concentrations, transport, and mitigation in indoor environments using low-cost air quality monitors and a portable air cleaner

In this study, we deployed multiple low-cost air quality monitors (AQMs) to investigate the transport of kitchen-generated fine particulate matter (PM2.5) into the bedrooms of four homes of different sizes over a period of more than nine weeks at each home. We also estimated the human exposure to PM2.5 associated with each microenvironment and evaluated the effects of using a portable air cleaner (PAC) to reduce those exposures. To select the best AQM for these analyses, we compared the field response of five commercially available models with that of a research-grade optical particle spectrometer. The AirVisual AQM showed the best correlation during collocation phases with R-2 values in the range of 0.5-0.9 during cooking and background periods for all locations. The bedroom monitors picked up cooking emissions from the kitchen area within 1-45 min depending on the layout of each home, and median PM2.5 concentrations in the bedroom were up to 30% lower than those in the kitchen. Results from the exposure analysis suggest that PAC use is an important intervention strategy for reducing personal PM2.5 exposure, especially in indoor environments where cooking is the main source of PM2.5 concentrations. In three of the four homes using PAC consistently in the kitchen or bedroom area during intensive cooking periods reduced overall exposure values by 30-90%. Moreover, during nighttime periods, PAC usage in the bedroom area yielded the lowest levels of PM2.5 exposure for all the homes.