Preliminary Seasonal Characterization of PM2.5 and Ozone Small Sensors

For the purpose of this study the PurpleAir sensor and the Aeroqual AQY1 were used in three different geographical regions and were intercompared with preliminary Department of Environmental Quality (DEQ) data from Pendleton OR, Richmond VA, and Hampton VA. Pendleton experiences colder temperatures and lower humidities, with higher PM2.5 levels in the summer due to forest fires, and use of woodburning stoves in the winter. Richmond is an urban city located along the Eastern Corridor. Hampton, located near the Chesapeake Bay, has a coastal influence. An evaluation of the PurpleAir sensor was made in all three locations, while the Aeroqual AQY1 was evaluated for Richmond and Hampton. PurpleAir PM2.5 levels are typically a factor of two higher when compared to DEQ PM2.5. Aeroqual PM2.5 is typically lower than DEQ PM2.5. Both Aeroqual and PurpleAir exhibit a dependence on relative humidity. Aeroqual ozone captures the diurnal trend when compared with DEQ ozone; however, the correlation varies with season.