Designing a Portable Particulate Matter Monitor

Air pollution affects billions of people around the world, yet policy makers often have difficulty obtaining precise, local air pollution measurements. Local air pollutant concentrations can vary dramatically depending on the possible presence of sources (factories, busy roads, residential wood burning). Though fixed-site air pollution monitoring is available, this method does not give a reliable measure of how PM_2.5 (particulate matter under 2.5 micrometers) concentrations vary with respect to space. We developed a portable method to measure local air pollution with an Alphasense OPC-N2 particulate matter monitor while commuting by foot, bicycle, or car. We collect GPS coordinates via the mobile app, Strava. Then we use RETIGO, EPA’s Real-Time Geospatial Data Viewer, to analyze the data and generate maps of the spatial variability of PM_2.5 concentrations along the sampling route. Preliminary data collected along a busy road yielded higher concentrations of PM_2.5 compared to areas with less traffic, confirming that traffic is contributing to local air pollution. This approach provides an intuitive visualization of possible local pollution sources that is accessible to both researchers and the general public. When validated by more experiments, this tool can be an easy way to measure local air pollution. This project can have important implications for how local air pollution can be measured and managed, which can greatly impact public health and environmental equity on a larger scale.