Climate change has increased the frequency and severity of wildfires in recent years. These fires produce a mix of gases and particles that impact air quality, leading to human and ecological health risk. At EPA's Clean Air Status & Trends Network (CASTNET) Georgia Station (GAS153) monitoring site, an analysis of black and brown carbon (BC & BrC) and particulate matter (PM) measurements provided information on CASTNET's role in supporting the monitoring of PM and PM speciation during wildfires. The Georgia site provides a location to observe the impact of smoke due to the incidence of prescribed burns in the area. To facilitate this analysis, different brands of low-cost optical PM sensors (LCOS) are co-located with a reference PM monitor (1400a Thermo scientific TEOM) and a 7 wavelengths Aethalometer (AE33) at GAS153 during a short-term monitoring intensive conducted in first quarter of 2024. The TEOM data provide a reference measurement to evaluate the performance of the LCOS. The aethalometer provides comparative measurements for the optical transmissometer analyses of BC on the Teflon filter within the CASTNET 3-stage filter pack, which were made using a SootScan Model OT21. The analysis of these measurements examines trends between PM and BC measurements. This study builds on recommendations from the Science Advisory Board and pushes the modernization of CASTNET forward through its exploration of PM composition and low-cost particulate matter sensor data.

¹ U.S. Environmental Protection Agency, Office of Air & Radiation, Office of Atmospheric Protection, Washington, DC

² School of Civil and Environmental Engineering, Georgia Tech, Atlanta, GA

³ School of Earth and Atmospheric Sciences, Georgia Tech, Atlanta, GA

⁴ WSP USA Environment & Infrastructure, Jacksonville, FL

⁵ WSP USA Environment & Infrastructure, Gainesville, FL

* Corresponding Author: delongmaxey.dakota@epa.gov