Winter and Wildfire Season Optical Characterization of Black and Brown Carbon in the El Paso-Ciudad Juárez Airshed

Black (EBC) and Brown (BrC) Carbon are ubiquitous constituents of atmospheric particulate matter that affect people’s health, disrupt ecosystems, modulate local global climate. Tracking the deposition sources these aerosol particles is essential to better understanding their multidimensional environmental impact. The main goal current study measure absorption coefficient (Babs) within Planetary Boundary Layer (PBL) El Paso (US)–Ciudad Juárez (Mexico) airshed assess contribution black brown carbon optical absorption. Measurements were taken during a summer, wildfire, winter season evaluate properties BC non-volatile BrC. presented variation from background Babs in late evening hours (3:00 PM midnight) due an increase biomass burning driven by lower temperatures. wildfire presents greatest EBC- BrC-rich smoke plumes arriving at this region US West seasonal wildfires. It was found international bridges’ vehicular traffic, waiting time cross back forth between both cities, added other anthropogenic activities, such as brick kiln emissions Ciudad Juarez, have created air pollution region. These pollutants include monoxide, sulfur dioxide, nitrogen nitric oxides, coarse fine dominated coefficients EBC BrC constitute what we called baseline Aided two photoacoustic Extinctiometers (PAX), operating 405 nm 870 wavelengths, connected 340 °C thermal denuder remove volatile organics, documented evaluated identify impact long-range transported western Single Scattering Albedo Absorption Ångstrom exponent calculated for summer season. Angstrom showed decrease events aging process. High-Resolution Rapid Refresh Smoke model, HRRR, Hybrid Single-Particle Lagrangian Integrated Trajectory HYSPLIT, used estimate particles. In addition, Vaisala Ceilometer employed vertical profile planetary boundary layer.