Comprehensive assessment of PM2.5physicochemical properties during the Southeast Asia dry season (southwest monsoon)

2016 ◽  
Vol 121 (24) ◽  
pp. 14,589-14,611 ◽  
Author(s):  
Md Firoz Khan ◽  
Nor Azura Sulong ◽  
Mohd Talib Latif ◽  
Mohd Shahrul Mohd Nadzir ◽  
Norhaniza Amil ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Southwest Monsoon ◽  
Dry Season ◽  
Comprehensive Assessment

scholarly journals Development of a Global Fire Weather Database

2015 ◽  
Vol 15 (6) ◽  
pp. 1407-1423 ◽  
Author(s):  
R. D. Field ◽  
A. C. Spessa ◽  
N. A. Aziz ◽  
A. Camia ◽  
A. Cantin ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Large Scale ◽  
Prediction Models ◽  
Dry Season ◽  
Weather Data ◽  
Data Sets ◽  
Fire Weather ◽  
Fire Weather Index ◽  
Mato Grosso ◽  
Global Database

Abstract. The Canadian Forest Fire Weather Index (FWI) System is the mostly widely used fire danger rating system in the world. We have developed a global database of daily FWI System calculations, beginning in 1980, called the Global Fire WEather Database (GFWED) gridded to a spatial resolution of 0.5° latitude by 2/3° longitude. Input weather data were obtained from the NASA Modern Era Retrospective-Analysis for Research and Applications (MERRA), and two different estimates of daily precipitation from rain gauges over land. FWI System Drought Code calculations from the gridded data sets were compared to calculations from individual weather station data for a representative set of 48 stations in North, Central and South America, Europe, Russia, Southeast Asia and Australia. Agreement between gridded calculations and the station-based calculations tended to be most different at low latitudes for strictly MERRA-based calculations. Strong biases could be seen in either direction: MERRA DC over the Mato Grosso in Brazil reached unrealistically high values exceeding DC = 1500 during the dry season but was too low over Southeast Asia during the dry season. These biases are consistent with those previously identified in MERRA's precipitation, and they reinforce the need to consider alternative sources of precipitation data. GFWED can be used for analyzing historical relationships between fire weather and fire activity at continental and global scales, in identifying large-scale atmosphere–ocean controls on fire weather, and calibration of FWI-based fire prediction models.

Characterizing two distinct biomass burning regimes over Southeast Asia and their impacts on regional air quality

2020 ◽  
Author(s):  
Margaret Marvin ◽  
Paul Palmer ◽  
Fei Yao ◽  
Barry Latter ◽  
Richard Siddans ◽  
...  
Keyword(s):  
Air Quality ◽  
Southeast Asia ◽  
Biomass Burning ◽  
Atmospheric Chemistry ◽  
Agricultural Waste ◽  
Critical Evaluation ◽  
Dry Season ◽  
Mitigation Strategies ◽  
Atmospheric Composition ◽  
Regional Air Quality

<p>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 (O<sub>3</sub>) and fine (radii smaller than 2.5 microns) particulate matter (PM<sub>2.5</sub>). Latitude-based differences in dry season timing and land use distinguish two regional biomass burning regimes: (1) agricultural waste burning on the peninsular mainland from February through April and (2) coastal peat burning across the equatorial islands in September and October. The type and amount of material burned determines the chemical composition of emissions and subsequently their impact on regional air quality. Understanding the individual and collective roles of these biomass burning regimes is a crucial step towards developing effective air quality mitigation strategies for Southeast Asia. Here, we use the nested GEOS-Chem atmospheric chemistry transport model (horizontal resolution of 0.25° x 0.3125°) to simulate fire-atmosphere interactions over Southeast Asia during March and September of 2014, when emissions peak from the two regional burning seasons. Based on our analysis of model output, we report how these two distinct biomass burning regimes impact the photochemical environment over Southeast Asia and what the resulting consequences are for surface air quality. We will also present a critical evaluation of our model using ground-based and satellite observations of atmospheric composition across the region.</p>

Trade, Ethnicity, and Identity in Island Southeast Asia

2021 ◽  
Author(s):  
Leonard Y. Andaya
Keyword(s):  
Southeast Asia ◽  
Early Modern Period ◽  
Southwest Monsoon ◽  
The Philippines ◽  
East Timor ◽  
Ethnic Communities ◽  
Island Southeast Asia ◽  
Trade Route ◽  
Monsoon Winds ◽  
East West

Island Southeast Asia (ISEA) consists of Malaysia, Singapore, Brunei, Indonesia, East Timor, and the Philippines and was the midway point in the vibrant East–West international maritime trade route that stretched from Europe, Middle East, East Africa, and South Asia to its west; and China, Ryukyu, Japan, and Korea to its east. The favored stop was along the Straits of Melaka, a calm haven protected from the force of the northeast and southwest monsoon winds. The stream of traders in the Straits enabled local ports to develop into international port cities, whose inhabitants created mixed communities and cultures: commodities were re-fashioned or re-packaged into hybrid forms to accommodate the distinctive tastes of different groups, while frequent and lengthy sojourns by traders resulted in liaisons that produced mixed offspring and cultures. Enhanced economic opportunities encouraged mobility and establishment of diaspora communities in the littoral. More sinister were the forced mobility through wars and slavery that produced reconstituted ethnic communities and new ethnicities and identities in the early modern period (c. 1400– c. 1830s).

scholarly journals Photochemical environment over Southeast Asia primed for hazardous ozone levels with influx of nitrogen oxides from seasonal biomass burning

2020 ◽  
Author(s):  
Margaret R. Marvin ◽  
Paul I. Palmer ◽  
Barry G. Latter ◽  
Richard Siddans ◽  
Brian J. Kerridge ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Southeast Asia ◽  
Biomass Burning ◽  
Atmospheric Chemistry ◽  
Tropospheric Ozone ◽  
Transport Model ◽  
Dry Season ◽  
Ozone Exposure ◽  
Ozone Production ◽  
Ozone Levels

Abstract. Mainland and maritime Southeast Asia are 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 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 impacts 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 of these burning areas, the underlying photochemical environment is generally NOx-limited, 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 272 premature deaths on mainland Southeast Asia in March of 2014 and another 273 deaths across Indonesia in September. Despite a positive model bias, hazardous ozone levels are confirmed by surface observations during both burning seasons.

scholarly journals Insights into seasonal variation of wet deposition over southeast Asia via precipitation adjustment from the findings of MICS-Asia III

2021 ◽  
Vol 21 (11) ◽  
pp. 8709-8734
Author(s):  
Syuichi Itahashi ◽  
Baozhu Ge ◽  
Keiichi Sato ◽  
Zhe Wang ◽  
Junichi Kurokawa ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Southeast Asia ◽  
Wet Deposition ◽  
Precipitation Amount ◽  
Model Performance ◽  
The Philippines ◽  
Dry Season ◽  
Phase Iii ◽  
Satellite Measurements ◽  
Research Attention

Abstract. Asia has attracted research attention because it has the highest anthropogenic emissions in the world, and the Model Inter-Comparison Study for Asia (MICS-Asia) phase III was carried out to foster our understanding of the status of air quality over Asia. This study analyzed wet deposition in southeast Asian countries (Myanmar, Thailand, Lao People's Democratic Republic (PDR), Cambodia, Vietnam, the Philippines, Malaysia, and Indonesia) with the aim of providing insights into the seasonal variation of wet deposition. Southeast Asia was not fully considered in MICS-Asia phase II due to a lack of observational data; however, the analysis period of MICS-Asia III, namely the year 2010, is covered by ground observations of the Acid Deposition Monitoring Network in East Asia (EANET), and the coordinated simulation domain was extended to cover these observation sites. The analyzed species are wet depositions of S (sulfate aerosol, sulfur dioxide (SO2), and sulfuric acid (H2SO4)), N (nitrate aerosol, nitrogen monoxide (NO), nitrogen dioxide (NO2), and nitric acid (HNO3)), and A (ammonium aerosol and ammonia (NH3)). The wet deposition simulated with seven models driven by a unified meteorological model in MICS-Asia III was used with the ensemble approach, which effectively modulates the differences in performance among models. By comparison with EANET observations, although the seven models generally captured the wet depositions of S, N, and A, there were difficulties capturing these in some cases. Considering the model performance for ambient aerosol concentrations over southeast Asia, this failure of models is considered to be related to the difficulty in capturing the precipitation in southeast Asia, especially during the dry and wet seasons. Generally, meteorological fields overestimate the precipitation during the dry season, which leads to the overestimation of wet deposition during this season. To overcome this, a precipitation-adjusted approach that scaled the modeled precipitation to the observed value was applied, and it was demonstrated that the model performance was improved. Satellite measurements were also used to adjust for precipitation data, which adequately accounted for the spatiotemporal precipitation patterns, especially in the dry season. As the statistical scores were mostly improved by this adjustment, the estimation of wet deposition with precipitation adjustment was considered to be superior. To utilize satellite measurements, the spatial distribution of wet deposition was revised. Based on this revision, it was found that Vietnam, Malaysia, and Indonesia were upward corrected, and Myanmar, Thailand, Lao PDR, Cambodia, and the Philippines were downward-corrected; these corrections were up to ±40 %. The improved accuracy of precipitation amount was key to estimating wet deposition in this study. These results suggest that the precipitation-adjusted approach has the potential to obtain accurate estimates of wet deposition through the fusion of models and observations.

scholarly journals Size-resolved Composition and Morphology of Particulate Matter During the Southwest Monsoon in Metro Manila, Philippines

2019 ◽  
Author(s):  
Melliza Templonuevo Cruz ◽  
Paola Angela Bañaga ◽  
Grace Betito ◽  
Rachel A. Braun ◽  
Connor Stahl ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Southeast Asia ◽  
Black Carbon ◽  
Soluble Fraction ◽  
Southwest Monsoon ◽  
Water Soluble ◽  
Water Soluble Fraction ◽  
Metro Manila ◽  
Wet Scavenging ◽  
Aerosol Properties

Abstract. This paper presents novel results from size-resolved particulate matter (PM) mass, composition, and morphology measurements conducted during the 2018 Southwest Monsoon (SWM) season in Metro Manila, Philippines. Micro-Orifice Uniform Deposit Impactors (MOUDIs) were used to collect PM sample sets that were analyzed for mass, morphology, black carbon (BC), and composition of the water-soluble fraction. The bulk of the PM mass was between 0.18–1.0 µm with a dominant mode between 0.32–0.56 µm. Similarly, most of the black carbon (BC) mass was found between 0.10–1.0 µm (the so-called Greenfield gap), peaking between 0.18–0.32 µm, where wet scavenging by rain is inefficient. In the range of 0.10–0.18 µm, BC constituted 78.1 % of the measured mass. Comparable contributions of BC (26.9 %) and the water-soluble fraction (31.3 %) to total PM were observed and most of the unresolved mass, which in total amounted to 41.8 %, was for diameters exceeding 0.32 µm. The water-soluble ions and elements exhibited an average combined concentration of 8.53 µg m−3, with SO42−, NH4+, NO3−, Na+, and Cl− as the major contributors. Positive Matrix Factorization (PMF) was applied to identify the possible aerosol sources and estimate their contribution to the water-soluble fraction of collected PM. The factor with the highest contribution was attributed to Aged/Transported aerosol (48.0 %) while Sea Salt (22.5 %) and “Combustion” emissions (18.7 %) had comparable contributions. Vehicular/Resuspended Dust (5.6 %) as well as Waste Processing emissions (5.1 %) were also identified. Microscopy analysis highlighted the ubiquity of non-spherical particles regardless of size, which is significant when considering calculations of parameters such as single scattering albedo, asymmetry parameter, and extinction efficiency. Results of this work have implications for aerosol impacts on public health, visibility, and regional climate as each of these depend on physicochemical properties of particles as a function of size. The significant influence from Aged/Transported aerosol to Metro Manila during the SWM season indicates that local sources in this megacity do not fully govern this coastal area's aerosol properties and that PM in Southeast Asia can travel long distances regardless of the significant precipitation and potential wet scavenging that could occur. That the majority of the regional aerosol mass burden is accounted for by BC and other insoluble components has important downstream effects on the aerosol hygroscopic properties, which depend on composition. The results are relevant for understanding the impacts of monsoonal features on size-resolved aerosol properties, notably aqueous processing and wet scavenging. Finally, the results of this work provide contextual data for future sampling campaigns in Southeast Asia such as the airborne component of the Cloud, Aerosol, and Monsoon Processes Philippines Experiment (CAMP2Ex) planned for the SWM season in 2019. Aerosol characterization via remote-sensing is notoriously difficult in Southeast Asia, which elevates the importance of datasets such as the one presented here.

scholarly journals An overview of transboundary haze studies: The underlying causes and regional disputes on Southeast Asia Region

2017 ◽  
Vol 13 (4) ◽  
pp. 747-753 ◽  
Author(s):  
Ku Mohd Kalkausar Ku Yusof ◽  
Azman Azid ◽  
Mohd Saiful Samsudin ◽  
Mohd. Asrul Jamalani
Keyword(s):  
Air Pollution ◽  
Southeast Asia ◽  
Effective Action ◽  
Turning Point ◽  
Dry Season ◽  
Forest Loss ◽  
Qualitative And Quantitative ◽  
Global Issue ◽  
Haze Pollution ◽  
Underlying Causes

Air pollution is now ranked as the ninth worst scenario globally and is expected to be the most serious global issue by the year 2050. The objective of this study is to get information regarding transboundary haze phenomenon blanketing the Southeast Asia that has been happened for decades ago. Various techniques such as qualitative and quantitative techniques have been applied to get the informative input detailed out by previous researchers. The finding shows that that the smoky haze occurred in the dry season, which at this point, the activities of cleaning and ground maintenance being carried out by Indonesian farmers. Indonesia is one of the countries drastically affected by deforestation process where their forest loss is 2% yr-1 which is equal to 1.9 million ha each year. The establishment of ASEAN in 2002 would be a turning point in addressing on more reliance on prevention and cooperation than establishing a liability regime or adopting legal instruments to protect the environment. However, the reflection of so-called ‘ASEAN Way', which preferred on non-interference in other states has inhibited the reliance on strong regional efforts in executing a more effective action in order to address and combat the transboundary haze pollution in Southeast Asia.

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