In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 21, No. 3 ( 2021-02-10), p. 1917-1935
Abstract:
Abstract. Mainland and maritime Southeast Asia is home to more than 655 million
people, representing nearly 10 % of the global population. The dry
season in this region is typically associated with intense biomass
burning activity, which leads to a significant increase in surface air
pollutants that are harmful to human health, including ozone
(O3). Latitude-based differences in the dry season and land use
distinguish two regional biomass burning regimes: (1) burning on the
peninsular mainland peaking in March and (2) burning across Indonesia
peaking in September. The type and amount of material burned in each
regime impact the emissions of nitrogen oxides (NOx = NO + NO2) and
volatile organic compounds (VOCs), which combine to
produce ozone. Here, we use the nested GEOS-Chem atmospheric chemistry
transport model (horizontal resolution of 0.25∘ × 0.3125∘),
in combination with satellite observations
from the Ozone Monitoring Instrument (OMI) and ground-based
observations from Malaysia, to investigate ozone photochemistry
over Southeast Asia in 2014. Seasonal cycles
of tropospheric ozone columns from OMI and GEOS-Chem
peak with biomass burning emissions.
Compared to OMI, the model has a mean annual bias of −11 %
but tends to overestimate tropospheric ozone near areas of seasonal fire activity.
We find that outside these burning areas,
the underlying photochemical environment is generally
NOx-limited and dominated by anthropogenic NOx and
biogenic non-methane VOC emissions. Pyrogenic emissions of NOx play a key
role in photochemistry, shifting towards more VOC-limited ozone production
and contributing about 30 % of the regional
ozone formation potential during both biomass burning seasons. Using the
GEOS-Chem model, we find that biomass burning activity coincides with
widespread ozone exposure at levels that exceed world public health
guidelines, resulting in about 260 premature deaths across
Southeast Asia in March 2014 and another 160 deaths
in September. Despite a positive model bias,
hazardous ozone levels are confirmed by surface observations during
both burning seasons.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-21-1917-2021
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2021
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
