Los Angeles Wildfires 2025: Satellite‐Based Emissions Monitoring and Air‐Quality Impacts

In January 2025, multiple wildfires erupted across the Los Angeles region, fueled by pro-longed dry conditions and intense Santa Ana winds. These events caused severe loss of life, extensive community damage, mass evacuations, and substantial air quality deterio-ration across Southern California and downwind regions through long-range smoke transport. This study integrates passive and active satellite observations to characterize the spatiotemporal and vertical distribution of wildfire emissions. TROPOMI (Sentinel-5P) and TEMPO provided high-resolution mapping of trace gases, including nitrogen dioxide (NO₂), carbon monoxide (CO), and formaldehyde (HCHO). Vertical column densities of NO₂ and HCHO reached 40 and 25 Pmolec/cm², respectively, representing more than a 250% increase in fire-affected zones. TEMPO observations revealed strong diurnal varia-bility and secondary photochemical production, offering insights into plume evolution on sub-daily scales. ATLID (EarthCARE) lidar profiling identified smoke layers concentrated between 1–3 km altitude, with optical properties characteristic of fresh biomass burning, and depolarization ratios indicating mixed particle morphology. The vertical profiling capability was critical for distinguishing transported smoke from boundary-layer pollu-tion and assessing radiative impacts. These findings demonstrate the value of synergistic passive–active satellite measurements in capturing the full extent of wildfire plumes and emphasize the need for integrated monitoring strategies as wildfire risk intensifies under climate change.