Air Quality Impacts of Biomass Burning Transport during 2019 CAMP2Ex using MUSICAv0 with Regional Refinement over Southeast Asia

The NASA Cloud, Aerosol and Monsoon Processes Philippines Experiment (CAMP2Ex) field campaign captured significant transport of biomass burning emissions from Maritime Continent (MC)/Indonesia fires to the Philippines. CAMP2Ex provided in-situ and remote sensing aerosol measurements during research flights over the smoke-impacted West Philippine Sea, and Metro Manila where urban emissions and transported smoke coexist. High temporal resolution Advanced Himawari Imager (AHI) Aerosol Optical Depth (AOD) retrievals provide further evidence of MC smoke impacts across the region. To assess air quality (AQ) impacts, simulations with the Multi-Scale Infrastructure for Chemistry and Aerosols (MUSICAv0) were conducted from 24 August to 05 October 2019. A variable resolution grid (~14 km) over the MC burning regions, and a refined ~7 km grid over Luzon was used to examine urban AQ in Metro Manila. MUSICAv0 aerosol distributions, simulated using specified oxidants, were evaluated against AHI AOD and CAMP2Ex aircraft vertical profiles. MUSICAv0 underestimated AHI AOD, especially over peat burning regions, due to underestimation of organic aerosols. CAMP2Ex flight data confirmed consistent column-wide underestimation of aerosol extinction. Two case studies were analyzed: (a) dense Borneo burning (16 September), where MUSICAv0 captured vertical structure of smoke transport to southern Philippines with aerosol layers up to 4 km; and (b) Manila urban plume (4 October), where model reproduced the mixed layer (ML) height and advection of lofted aerosols over land into the Manila Bay free troposphere. These findings demonstrate MUSICAv0’s capability in representing multi-scale tropical atmospheric chemistry, with future improvements focused on peat emissions and full gas-phase chemistry.