04 Aug 2023
 | 04 Aug 2023

Uncertainties from biomass burning aerosols in air quality models obscure public health impacts in Southeast Asia

Margaret R. Marvin, Paul I. Palmer, Fei Yao, Mohd Talib Latif, and Md Firoz Kahn

Abstract. Models suggest that biomass burning causes thousands of premature deaths annually in Southeast Asia due to excessive exposure to particulate matter (PM) in smoke. However, measurements of surface air quality are sparse across the region, and consequently estimates for the public health impacts of seasonal biomass burning are not well constrained. We use the nested GEOS-Chem model of chemistry and transport (horizontal resolution of 0.25° × 0.3125°) to simulate atmospheric composition over Southeast Asia during the peak burning months of March and September in moderate burning year 2014. Model simulations with GEOS-Chem indicate that regional surface levels of PM2.5 (fine particulate matter with a diameter of < 2.5 microns) greatly exceed world health guidelines during the burning seasons, resulting in up to 10,000 premature deaths in a single month. However, the model substantially underestimates the regional aerosol burden compared to satellite observations of aerosol optical depth (AOD) (20–52 %) and ground-based observations of PM (up to 54 %), especially during the early burning season in March. We investigate potential uncertainties limiting the model representation of biomass burning aerosols and develop sensitivity simulations that improve model-measurement agreement in March (to within 31 %) and increase the estimated number of PM2.5-related premature deaths that month by almost half. Our modifications have a much smaller impact on the same metrics for September, but we find that this is due to canceling errors in the model. Compared to PM2.5 simulated directly with GEOS-Chem, PM2.5 derived from satellite AOD is less sensitive to model uncertainties and may provide a more accurate foundation for public health calculations in the short term, but continued investigation of uncertainties is still needed so that model analysis can be applied to support mitigation efforts. Further reduction of uncertainties can be achieved with the deployment of more aerosol measurements across Southeast Asia.

Margaret R. Marvin et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-1232', Anonymous Referee #1, 08 Sep 2023
  • RC2: 'Comment on egusphere-2023-1232', Anonymous Referee #2, 16 Sep 2023
  • AC1: 'Comment on egusphere-2023-1232', Margaret Marvin, 24 Nov 2023

Margaret R. Marvin et al.

Model code and software

geoschem/geos-chem: GEOS-Chem 12.5.0 (Version 12.5.0) The International GEOS-Chem User Community

Margaret R. Marvin et al.


Total article views: 562 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
407 140 15 562 7 11
  • HTML: 407
  • PDF: 140
  • XML: 15
  • Total: 562
  • BibTeX: 7
  • EndNote: 11
Views and downloads (calculated since 04 Aug 2023)
Cumulative views and downloads (calculated since 04 Aug 2023)

Viewed (geographical distribution)

Total article views: 545 (including HTML, PDF, and XML) Thereof 545 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 08 Dec 2023
Short summary
We use an atmospheric chemistry model to investigate aerosols emitted from fire activity across Southeast Asia. We find that the limited nature of measurements in this region leads to large uncertainties that significantly hinder the model representation of these aerosols and their impacts on air quality. As a result, the number of monthly attributable deaths is underestimated by as many as 4,500, particularly in March at the peak of the mainland burning season.