Work

Technical note: Apportionment of Southeast Asian biomass burning and urban influence via in situ trace gas enhancement ratios

Year: 2025

Type: article

Abstract: . Biomass burning and urban emissions are major contributors to poor air quality throughout Southeast Asia. Understanding these emissions is critical for predicting and mitigating their health impacts. The Cloud, Aerosol and Monsoon Processes Philippines Experiment (CAMP2Ex) field project in 2019 focused on regional sources in Southeast Asia and their effects on aerosol/cloud interactions using a combination of airborne, shipboard, and ground-based platforms. These measurements sampled a variety of pollution sources over the Sulu, Philippine, and South China seas during both the southwest monsoon and monsoon transition periods. CAMP2Ex provided a unique opportunity to examine how local and transported emissions affected airmass chemical composition and air quality. Correlations in airborne in situ gas enhancement ratios of CH4 to CO were used to separate airmasses with predominantly biomass burning, urban, or mixed influence, and isolating contributions from differing urban sources. HYSPLIT backtrajectory analysis was used to identify airmass sources, and resulting source regimes were examined for differences in ozone, reactive nitrogen, and aerosol chemical composition. ΔO3/ΔCO enhancement ratios were observed to be constant between urban source regimes, yet ΔNOy/ΔCO enhancement ratios differed across these regimes. For biomass burning sources, enhancement ratios in ΔO3/ΔCO were lower than those reported by previous studies in this region. Organic aerosol mass fractions were 2–3 times higher in biomass burning influenced regimes compared to urban regimes. This technique represents a simple yet novel approach for separating emission influences in a complex environment that enable isolation of emission sources requiring relatively simple measurements.

Source: Atmospheric chemistry and physics

DOI: 10.5194/acp-25-17387-2025

Authors: Joshua P. DiGangi, Glenn S. Diskin, Subin Yoon, Sergio L. Alvarez, James H. Flynn, Claire E. Robinson, Michael A. Shook, K. Lee Thornhill, Edward L. Winstead, Luke D. Ziemba, Maria Obiminda L. Cambaliza, James B. Simpas, Miguel Ricardo A. Hilario, Armin Sorooshian

Institutions: Langley Research Center, Scripps Institution of Oceanography, University of California San Diego, University of Houston, Analytical Mechanics Associates (United States), Ateneo de Manila University, Manila Observatory, University of Arizona

Language: English

Topic: Atmospheric chemistry and aerosols

Subfield: Atmospheric Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $1,725

Funders: National Aeronautics and Space Administration, Nuclear Safety and Security Commission, National Oceanic and Atmospheric Administration, Office of Naval Research

Award: THE OBJECTIVE OF THE PROPOSED 5-YEAR PROJECT IS TO DEPLOY THE DIFFERENTIAL AEROSOL SIZING AND HYGROSCOPICITY SPECTROMETER PROBE (DASH-SP) ON THE NASA P-3B DURING THE CLOUD AND AEROSOL MONSOONAL PROCESSES-PHILIPPINES EXPERIMENT (CAMP2EX) FOLLOWED BY PROCESSING DISSEMINATION AND ANALYSIS OF COLLECTED DATA. THE DASH-SP WAS DEVELOPED SPECIFICALLY FOR AIRCRAFT EXPERIMENTS TO PROVIDE RAPID MEASUREMENTS OF SIZE-RESOLVED AEROSOL HYGROSCOPIC GROWTH FACTOR (GF = RATIO OF HUMIDIFIED DIAMETER TO DRY DIAMETER) AND THE REAL COMPONENT OF THE DRY PARTICLE REFRACTIVE INDEX (RI). RAPID AND SIZE-RESOLVED MEASUREMENTS OF THIS NATURE HAVE YET TO BE COLLECTED ON AN AIRBORNE PLATFORM IN THE STUDY REGION WHICH CAN HELP ADVANCE KNOWLEDGE OF AEROSOL-WATER INTERACTIONS AND AEROSOL RADIATIVE FORCING. HIGH TIME RESOLUTION DATA (AS FAST AS ~1 HZ) FROM THE DASH-SP CAN BE MEANINGFULLY COMPARED WITH OTHER SIMULTANEOUS RAPID MEASUREMENTS INCLUDING THOSE FOR GAS- AND AEROSOL-PHASE COMPOSITION AS WELL AS CLOUD CONDENSATION NUCLEI (CCN) CONCENTRATIONS ALL OF WHICH CAN BE USED TO CONDUCT CLOSURE STUDIES TO VALIDATE AND IMPROVE MODEL PARAMETERIZATIONS OF WATER UPTAKE. ADDITIONALLY THE PROPOSED MEASUREMENTS OF AEROSOL HYGROSCOPICITY AND REFRACTIVE INDEX WILL BE HELPFUL FOR USING AND INTERPRETING REMOTE SENSING DATA. SPECIFIC PROJECT TASKS WILL INCLUDE THE FOLLOWING IN ORDER OF OCCURRENCE: (I) PREPARATION AND INTEGRATION OF THE DASH-SP ON THE P-3B; (II) OPERATION OF THE DASH-SP DURING TEST AND RESEARCH FLIGHTS; (III) SUBMISSION OF PRELIMINARY DATA AFTER EACH FLIGHT; (IV) DE-INTEGRATION OF DASH-SP AFTER THE CAMPAIGN; (V) SUBMISSION OF FINAL DATA; AND (VI) DATA ANALYSIS AND COLLABORATION FOCUSED ON PEER-REVIEWED PUBLICATION(S) AS WELL AS PRESENTATIONS AT MAJOR SCIENTIFIC CONFERENCES AND SCIENCE TEAM MEETINGS. THE DASH-SP HAS BEEN SUCCESSFULLY DEPLOYED IN FOUR AIRCRAFT FIELD STUDIES INCLUDING ON THE NASA DC-8 DURING DC3 AND SEAC4RS. THE PROPOSED RESEARCH IS DIRECTLY RELEVANT TO NASA STRATEGIC GOALS AS THE DATA COLLECTED WILL HELP ADDRESS HOW NATURAL AND HUMANINDUCED CHANGES ALTER AIR QUALITY AS WELL AS THE PLANET S RADIATION BALANCE AND HYDROLOGIC CYCLE. DASH-SP MEASUREMENTS HAVE DIRECT RELEVANCE TO THE RADIATION SCIENCES PROGRAM WHICH SUPPORTS STUDIES TO IMPROVE THE THEORETICAL UNDERSTANDING OF RADIATIVE TRANSFER AS WELL AS FIELD MEASUREMENTS OF AEROSOL AND CLOUD PARTICLE CONCENTRATION COMPOSITION MICROPHYSICS AND OPTICAL PROPERTIES. THE RESULTS WILL BE USED TO IMPROVE PARAMETERIZATIONS OF AEROSOL-WATER INTERACTIONS IN ATMOSPHERIC MODELS. THE COLLECTED DATA WILL BE HIGHLY COMPLEMENTARY TO OTHER MEASUREMENTS ON THE P-3B DURING CAMP2EX IN ADDITION TO BEING BENEFICIAL FOR INTERPRETING AND USING REMOTE SENSING DATA.

OpenAlex ID: W4416901066

FWCI: 0.446

Cites: 37

Cited by: 1

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