Title: Biomass burning aerosols and the low-visibility events in Southeast Asia

Abstract

Fires including peatland burning in Southeast Asia have become a major concern to the general public as well as governments in the region. This is because aerosols emitted from such fires can cause persistent haze events under certain weather conditions in downwind locations, degrading visibility and causing human health issues. In order to improve our understanding of the spatiotemporal coverage and influence of biomass burning aerosols in Southeast Asia, we have used surface visibility and particulate matter concentration observations, supplemented by decade-long (2003 to 2014) simulations using the Weather Research and Forecasting (WRF) model with a fire aerosol module, driven by high-resolution biomass burning emission inventories. Here, we find that in the past decade, fire aerosols are responsible for nearly all events with very low visibility (< 7 km). Fire aerosols alone are also responsible for a substantial fraction of low-visibility events (visibility < 10 km) in the major metropolitan areas of Southeast Asia: up to 39 % in Bangkok, 36 % in Kuala Lumpur, and 34 % in Singapore. Biomass burning in mainland Southeast Asia accounts for the largest contribution to total fire-produced PM_2.5 in Bangkok (99 %), while biomass burning in Sumatra is a major contributor to fire-producedmore » PM_2.5 in Kuala Lumpur (50 %) and Singapore (41 %). In order to examine the general situation across the region, we have further defined and derived a new integrated metric for 50 cities of the Association of Southeast Asian Nations (ASEAN): the haze exposure day (HED), which measures the annual exposure days of these cities to low visibility (< 10 km) caused by particulate matter pollution. It is shown that HEDs have increased steadily in the past decade across cities with both high and low populations. Fire events alone are found to be responsible for up to about half of the total HEDs. These results suggest that in order to improve the overall air quality in Southeast Asia, mitigation policies targeting both biomass burning and fossil fuel burning sources need to be implemented.« less

Authors:

Lee, Hsiang-He ;

• Search DOE PAGES for author "Lee, Hsiang-He"
• Search DOE PAGES for ORCID "0000-0002-5140-7324"

Bar-Or, Rotem Z.; Wang, Chien

• Search DOE PAGES for author "Wang, Chien"
• Search DOE PAGES for ORCID "0000-0002-3979-4747"

Publication Date:

Mon Jan 23 00:00:00 EST 2017

Research Org.:

Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1341342

Alternate Identifier(s):

OSTI ID: 1366496

Grant/Contract Number:  

FG02-94ER61937

Resource Type:

Published Article

Journal Name:

Atmospheric Chemistry and Physics (Online)

Additional Journal Information:

Journal Name: Atmospheric Chemistry and Physics (Online) Journal Volume: 17 Journal Issue: 2; Journal ID: ISSN 1680-7324

Publisher:

Copernicus Publications, EGU

Country of Publication:

Germany

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; 09 BIOMASS FUELS