1
|
Cao N, Chen L, Liu Y, Wang J, Yang S, Su D, Mi K, Gao S, Zhang H. Spatiotemporal distribution, light absorption characteristics, and source apportionments of black and brown carbon in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 919:170796. [PMID: 38336053 DOI: 10.1016/j.scitotenv.2024.170796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/30/2024] [Accepted: 02/06/2024] [Indexed: 02/12/2024]
Abstract
Black carbon (BC) and brown carbon (BrC) are aerosols that absorb light and thereby contribute to climate change. In this study, the light absorption properties and spatiotemporal distributions of equivalent BC (eBC) and BrC aerosols were determined based on continuous measurements of aerosol light absorption from January to August 2017, using a seven-channel aethalometer at 49 sampling sites in China. The source apportionments of BC and BrC were identified using the BC/PM2.5, absorption Ångström exponent, the concentration-weighted trajectory method, and the random forest model. Based on the results, BC was the dominant light absorber, whereas BrC was responsible for a higher proportion of the light absorption in northern compared to southern China. The light absorption of BrC was highest in winter (34.3 Mm-1), followed by spring (19.0 Mm-1) and summer (3.6 Mm-1). The combustion of liquid fuels accounted for over 50 % of the light absorption coefficient of BC in most cities and the importance of carbon monoxide (CO) and nitrogen dioxide (NO2) was over 10 % for BC emitted by liquid fuel combustion, based on the random forest model. The contribution of solid fuel combustion to BC in the north was larger than that in the southern regions as coal combustion and crop residue burning are important emission sources of BC in most northern cities. The contribution of primary BrC to light absorption was high in some northern cities, whereas that of secondary BrC was prevalent in some southern cities. The diurnal variations in secondary BrC were affected by changes in odd oxygen and relative humidity, which promoted the photobleaching of the chromophores and aqueous-phase reactions of secondary BrC.
Collapse
Affiliation(s)
- Nan Cao
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Li Chen
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China.
| | - Yusi Liu
- State Key Laboratory of Severe Weather, Key Laboratory for Atmospheric Chemistry of China Meteorology Administration, Chinese Academy of Meteorological Sciences, Beijing 100081, China.
| | - Jing Wang
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Shuangqin Yang
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Die Su
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Ke Mi
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Shuang Gao
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Hu Zhang
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
| |
Collapse
|
2
|
Pani SK, Huang HY, Wang SH, Holben BN, Lin NH. Long-term observation of columnar aerosol optical properties over the remote South China Sea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:167113. [PMID: 37717748 DOI: 10.1016/j.scitotenv.2023.167113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 09/13/2023] [Accepted: 09/13/2023] [Indexed: 09/19/2023]
Abstract
The South China Sea (SCS) is a receptor of pollution sources from various parts of Asia and is heavily impacted by strong meteorological systems, which thus dictate aerosol variability over the region. This study analyzes long-term aerosol optical properties observed at Dongsha Island (a representative site in northern SCS) from 2009 to 2021 and Taiping Island (a representative site in southern SCS) from 2012 to 2021 to better apprehend the temporal evolution of columnar aerosols over the SCS. The noticeable difference in loadings, optical properties, and compositions of aerosols between northern and southern SCS was due to the influence of dissimilar emission sources and transport mechanisms. Column-integrated aerosol optical depth (AOD) over northern SCS (range of monthly mean at 500 nm; 0.12-0.51) was significantly greater than southern SCS (0.09-0.21). The maximum AOD in March (0.51 ± 0.28) at Dongsha was attributed to westerlies coupled with biomass-burning (BB) emissions from peninsular Southeast Asia, whereas the maximum AOD at Taiping in September (0.21 ± 0.25) was owing to various pollution from the Philippines, Malaysia, and Indonesia. Fine-mode aerosol dominated over northern SCS (range of monthly mean Angstrom exponent for 440-870 nm: 0.85-1.36) due to substantial influence from continental sources including anthropogenic and BB emissions while coarse-mode particles dominated over southern SCS (0.54-1.28) due to relatively more influence from marine source. More absorbing columnar aerosols prevailed over northern SCS (range of monthly mean single scattering albedo at 675 nm: 0.92-0.99) compared to southern SCS (0.95-0.98) owing to differences in aerosol composition with respect to sources. Special pollution events showcased possible significant impacts on marine ecosystems and regional climate. This study encourages the establishment of more ground-based aerosol monitoring networks and the inclusion of modeling simulations to comprehend the complex nature of aerosol over this vast marginal sea.
Collapse
Affiliation(s)
- Shantanu Kumar Pani
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan
| | - Hsiang-Yu Huang
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan
| | - Sheng-Hsiang Wang
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan; Center for Environmental Monitoring and Technology, National Central University, Taoyuan 32001, Taiwan.
| | - Brent N Holben
- Goddard Space Flight Center, NASA, Greenbelt, MD 20771, USA
| | - Neng-Huei Lin
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan; Center for Environmental Monitoring and Technology, National Central University, Taoyuan 32001, Taiwan.
| |
Collapse
|
3
|
Bhardwaj A, Haswani D, Yadav K, Sunder Raman R. PM 2.5 carbonaceous components and mineral dust at a COALESCE network site - Bhopal, India: Estimating site-specific optical characteristics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 880:163277. [PMID: 37028678 DOI: 10.1016/j.scitotenv.2023.163277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/14/2023] [Accepted: 03/31/2023] [Indexed: 05/27/2023]
Abstract
Atmospheric PM2.5 thermal elemental carbon (EC), optical black carbon (BC), brown carbon (BrC), and mineral dust (MD) were characterized during a field campaign at a regionally representative site (Bhopal, central India) all year-long during 2019. In this study, the optical characteristics of PM2.5 during 'EC-rich', 'OC-rich', and 'MD-rich' days were used in a three-component model to estimate site-specific Absorption Ångström exponent (AAE) and absorption coefficient (babs) of light-absorbing PM2.5 constituents. The AAE for 'EC-rich', 'OC-rich', and 'MD-rich' days were 1.1 ± 0.2, 2.7 ± 0.3, and 3.0 ± 0.9, respectively. The percentage contribution of calculated babs of EC, BrC, and MD to the total babs at 405 nm was dominated by EC during the entire study period (EC; 64 % ± 36 %, BrC: 30 % ± 5 %, MD: 10 % ± 1 %). Further, site-specific mass absorption cross-section (MAC) values were calculated to assess the impact of their use over the use of manufacturer-specified MAC values in estimating BC concentrations. The r2 between thermal EC and optical BC was higher (r2 = 0.67, slope = 1.1) when daily site-specific MAC values were used rather than using the default MAC value (16.6 m2 g-1; r2 = 0.54 and slope = 0.6). Overall, had the default MAC880 been used instead of the site-specific values, we would have underestimated the BC concentration by 39 % ± 18 % during the study period.
Collapse
Affiliation(s)
- Ankur Bhardwaj
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal by-pass road, Bhauri, Bhopal 462066, Madhya Pradesh, India
| | - Diksha Haswani
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal by-pass road, Bhauri, Bhopal 462066, Madhya Pradesh, India
| | - Kajal Yadav
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal by-pass road, Bhauri, Bhopal 462066, Madhya Pradesh, India
| | - Ramya Sunder Raman
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal by-pass road, Bhauri, Bhopal 462066, Madhya Pradesh, India.
| |
Collapse
|
4
|
De Haan DO, Hawkins LN, Wickremasinghe PD, Andretta AD, Dignum JR, De Haan AC, Welsh HG, Pennington EA, Cui T, Surratt JD, Cazaunau M, Pangui E, Doussin JF. Brown Carbon from Photo-Oxidation of Glyoxal and SO 2 in Aqueous Aerosol. ACS EARTH & SPACE CHEMISTRY 2023; 7:1131-1140. [PMID: 37223425 PMCID: PMC10201569 DOI: 10.1021/acsearthspacechem.3c00035] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 04/12/2023] [Accepted: 04/14/2023] [Indexed: 05/25/2023]
Abstract
Aqueous-phase dark reactions during the co-oxidation of glyoxal and S(IV) were recently identified as a potential source of brown carbon (BrC). Here, we explore the effects of sunlight and oxidants on aqueous solutions of glyoxal and S(IV), and on aqueous aerosol exposed to glyoxal and SO2. We find that BrC is able to form in sunlit, bulk-phase, sulfite-containing solutions, albeit more slowly than in the dark. In more atmospherically relevant chamber experiments where suspended aqueous aerosol particles are exposed to gas-phase glyoxal and SO2, the formation of detectable amounts of BrC requires an OH radical source and occurs most rapidly after a cloud event. From these observations we infer that this photobrowning is caused by radical-initiated reactions as evaporation concentrates aqueous-phase reactants and aerosol viscosity increases. Positive-mode electrospray ionization mass spectrometric analysis of aerosol-phase products reveals a large number of CxHyOz oligomers that are reduced rather than oxidized (relative to glyoxal), with the degree of reduction increasing in the presence of OH radicals. This again suggests a radical-initiated redox mechanism where photolytically produced aqueous radical species trigger S(IV)-O2 auto-oxidation chain reactions, and glyoxal-S(IV) redox reactions especially if aerosol-phase O2 is depleted. This process may contribute to daytime BrC production and aqueous-phase sulfur oxidation in the atmosphere. The BrC produced, however, is about an order of magnitude less light-absorbing than wood smoke BrC at 365 nm.
Collapse
Affiliation(s)
- David O. De Haan
- Department
of Chemistry and Biochemistry, University
of San Diego, 5998 Alcala Park, San Diego, California 92117, United States
| | - Lelia N. Hawkins
- Department
of Chemistry, Harvey Mudd College, 301 Platt Blvd, Claremont, California 91711, United States
| | - Praveen D. Wickremasinghe
- Department
of Chemistry and Biochemistry, University
of San Diego, 5998 Alcala Park, San Diego, California 92117, United States
| | - Alyssa D. Andretta
- Department
of Chemistry and Biochemistry, University
of San Diego, 5998 Alcala Park, San Diego, California 92117, United States
| | - Juliette R. Dignum
- Department
of Chemistry and Biochemistry, University
of San Diego, 5998 Alcala Park, San Diego, California 92117, United States
| | - Audrey C. De Haan
- Department
of Chemistry and Biochemistry, University
of San Diego, 5998 Alcala Park, San Diego, California 92117, United States
| | - Hannah G. Welsh
- Department
of Chemistry, Harvey Mudd College, 301 Platt Blvd, Claremont, California 91711, United States
| | - Elyse A. Pennington
- Department
of Chemistry, Harvey Mudd College, 301 Platt Blvd, Claremont, California 91711, United States
| | - Tianqu Cui
- Department
of Environmental Sciences and Engineering, Gillings School of Global
Public Health, University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27599, United States
| | - Jason D. Surratt
- Department
of Environmental Sciences and Engineering, Gillings School of Global
Public Health, University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27599, United States
- Department
of Chemistry, College of Arts and Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Mathieu Cazaunau
- Laboratoire
Interuniversitaire des Systèmes Atmosphériques (LISA),
UMR7583, CNRS, Institut Pierre Simon Laplace (IPSL), Université Paris-Est-Créteil (UPEC) et Université
Paris Diderot (UPD), Créteil 94010, France
| | - Edouard Pangui
- Laboratoire
Interuniversitaire des Systèmes Atmosphériques (LISA),
UMR7583, CNRS, Institut Pierre Simon Laplace (IPSL), Université Paris-Est-Créteil (UPEC) et Université
Paris Diderot (UPD), Créteil 94010, France
| | - Jean-François Doussin
- Laboratoire
Interuniversitaire des Systèmes Atmosphériques (LISA),
UMR7583, CNRS, Institut Pierre Simon Laplace (IPSL), Université Paris-Est-Créteil (UPEC) et Université
Paris Diderot (UPD), Créteil 94010, France
| |
Collapse
|
5
|
Amin M, Prajati G, Humairoh GP, Putri RM, Phairuang W, Hata M, Furuuchi M. Characterization of size-fractionated carbonaceous particles in the small to nano-size range in Batam city, Indonesia. Heliyon 2023; 9:e15936. [PMID: 37215863 PMCID: PMC10192538 DOI: 10.1016/j.heliyon.2023.e15936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 04/08/2023] [Accepted: 04/27/2023] [Indexed: 05/24/2023] Open
Abstract
A cascade impactor type sampler equipped with an inertial filter was used to collect size-segregated particles down to ultrafine particles (UFPs or PM0.1) on Batam Island in Sumatra, Indonesia, bordered by Singapore and Malaysia during a wet and the COVID-19 pandemic season in 2021. Carbonaceous species, including organic carbon (OC) and elemental carbon (EC), were analyzed by a thermal/optical carbon analyzer to determine the carbon species and their indices. The average UFP was 3.1 ± 0.9 μg/m3, which was 2-4 times lower than in other cities in Sumatra during the same season in the normal condition. The PMs mass concentration was largely affected by local emissions but long-range transportation of particles from Singapore and Malaysia was also not negligible. The air mass arrived at the sampling site passed the ocean, which introduced out clean air with a low level of PMs. The backward trajectory of the air mass and the largest fraction of OC2 and OC3 in all sizes was identified as being transported from the 2 above countries. OC is the dominant fraction in TC and the ratio of carbonaceous components indicated that origin of all particle sizes was predominantly vehicle emissions. UFPs were dominantly emitted from vehicles exhaust emission, while coarser particles (>10 μm) were influenced by the non-exhaust emissions, such as tire wear. Other particles (0.5-1.0; 1.0-2.5; and 2.5-10 μm) were slightly affected by biomass burning. The effective carbon ratio (ECR) and inhalation dose (ID) related EC indicated that finer particles or UFPs and PM0.5-1 contributed more to human health and global warming.
Collapse
Affiliation(s)
- Muhammad Amin
- Faculty of Geosciences and Civil Engineering, Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan
- Faculty of Engineering, Maritim University of Raja Ali Haji, Tanjung Pinang, Kepulauan Riau, 29115, Indonesia
| | - Gita Prajati
- Environmental Engineering Department, Universitas Universal, Batam, Kepulauan Riau, 29456, Indonesia
| | - Gita Pati Humairoh
- Environmental Engineering Department, Universitas Universal, Batam, Kepulauan Riau, 29456, Indonesia
| | - Rahmi Mulia Putri
- Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan
| | - Worradorn Phairuang
- Faculty of Geosciences and Civil Engineering, Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan
| | - Mitsuhiko Hata
- Faculty of Geosciences and Civil Engineering, Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan
| | - Masami Furuuchi
- Faculty of Geosciences and Civil Engineering, Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan
- Faculty of Environmental Management, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand
| |
Collapse
|
6
|
Ho CS, Lv Z, Peng J, Zhang J, Choe TH, Zhang Q, Du Z, Mao H. Optical properties of vehicular brown carbon emissions: Road tunnel and chassis dynamometer tests. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 320:121037. [PMID: 36641064 DOI: 10.1016/j.envpol.2023.121037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/04/2023] [Accepted: 01/06/2023] [Indexed: 06/17/2023]
Abstract
Brown carbon (BrC), as an important light-absorbing aerosol, significantly impacts regional and global climate. Vehicle emission is a nonnegligible source of BrC, but the optical properties of BrC emitted from vehicles remain poorly understood. This study evaluates the absorption Ångström exponent (AAE) of traffic-related light-absorbing aerosols (i.e., AAETr) and the absorption emission factor (EFabs) of vehicular BrC via chassis dynamometer tests and a road tunnel measurement in Tianjin, China. AAETr are estimated as 0.98-1.33 and 1.11 ± 0.001 for tested vehicles and on-road vehicle fleet, respectively. The AAE of vehicular BrC (AAEBrC) is 3.83 ± 0.092 for on-road vehicle fleet. The vehicle technology updates effectively reduce the EFabs of vehicular BrC. Among the four tested China 5 and China 6 gasoline vehicles in the chassis dynamometer tests, BrC EFabs of China 5 gasoline direct injection vehicle is the highest, while China 6 mixing fuel injection vehicle exhibits the lowest EFabs. The BrC EFabs of on-road vehicle fleet at 370 nm wavelength are 0.081 ± 0.0058 m2 kg-1 for mixed fleet, 0.074 ± 0.018 m2 kg-1 for gasoline vehicles (GVs), and 1.66 ± 0.71 m2 kg-1 for diesel vehicles (DVs) in the tunnel measurement. EFabs of GV fleet in the road tunnel is higher than China 5 and China 6 vehicles, as China 1-4 vehicles accounted for 26.8% of the total vehicle fleet in the tunnel. EFabs of vehicular BrC are lower than those from biomass burning and coal combustion emissions. The light absorption of BrC from GVs and DVs accounts for 7.2 ± 2.1% and 1.5 ± 0.77% of total traffic-related absorption at 370 nm, respectively. Our study provides optical features of BrC from vehicle source and could contribute to estimating the impacts of vehicular aerosol emissions on global and regional climate change.
Collapse
Affiliation(s)
- Chung Song Ho
- Tianjin Key Laboratory of Urban Transport Emission Research & State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China; High-Tech Research and Development Center, Kim Il Sung University, Pyongyang, 999093, Democratic People's Republic of Korea
| | - Zongyan Lv
- Tianjin Key Laboratory of Urban Transport Emission Research & State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China
| | - Jianfei Peng
- Tianjin Key Laboratory of Urban Transport Emission Research & State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China.
| | - Jinsheng Zhang
- Tianjin Key Laboratory of Urban Transport Emission Research & State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China
| | - Tong-Hyok Choe
- Faculty of Global Environmental Science, Kim Il Sung University, Pyongyang, 999093, Democratic People's Republic of Korea
| | - Qijun Zhang
- Tianjin Key Laboratory of Urban Transport Emission Research & State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China
| | - Zhuofei Du
- Tianjin Key Laboratory of Urban Transport Emission Research & State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China
| | - Hongjun Mao
- Tianjin Key Laboratory of Urban Transport Emission Research & State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China
| |
Collapse
|
7
|
Suriyawong P, Chuetor S, Samae H, Piriyakarnsakul S, Amin M, Furuuchi M, Hata M, Inerb M, Phairuang W. Airborne particulate matter from biomass burning in Thailand: Recent issues, challenges, and options. Heliyon 2023; 9:e14261. [PMID: 36938473 PMCID: PMC10018570 DOI: 10.1016/j.heliyon.2023.e14261] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/28/2023] [Accepted: 02/28/2023] [Indexed: 03/08/2023] Open
Abstract
Many of the current atmospheric environmental problems facing Thailand are linked to air pollution that is largely derived from biomass burning. Different parts of Thailand have distinctive sources of biomass emissions that affect air quality. The main contributors to atmospheric particulate matter (PM), especially the PM2.5 fraction in Thailand, were highlighted in a recent study of PM derived from biomass burning. This review is divided into six sections. Section one is an introduction to biomass burning in Thailand. Section two covers issues related to biomass burning for each of the four main regions in Thailand, including Northern, Northeastern, Central, and Southern Thailand. In northern Thailand, forest fires and the burning of crop residues have contributed to air quality in the past decade. The northeast region is mainly affected by the burning of agricultural residues. However, the main contributor to PM in the Bangkok Metropolitan Region is motor vehicles and crop burning. In Southern Thailand, the impact of agoindustries, biomass combustion, and possible agricultural residue burning are the primary sources, and cross-border pollution is also important. The third section concerns the effect of biomass burning on human health. Finally, perspectives, new challenges, and policy recommendations are made concerning improving air quality in Thailand, e.g., forest fuel management and biomass utilization. The overall conclusions point to issues that will have a long-term impact on achieving a blue sky over Thailand through the development of coherent policies and the management of air pollution and sharing this knowledge with a broader audience.
Collapse
Affiliation(s)
- Phuchiwan Suriyawong
- Research Unit for Energy, Economic, And Ecological Management (3E), Science and Technology Research Institute, Chiang Mai University, Chiang Mai, 50200 Thailand
| | - Santi Chuetor
- Department of Chemical Engineering, Faculty of Engineering, King Mongkut's University of Technology North Bangkok, Bangkok, 10800 Thailand
| | - Hisam Samae
- Research Unit for Energy, Economic, And Ecological Management (3E), Science and Technology Research Institute, Chiang Mai University, Chiang Mai, 50200 Thailand
| | - Suthida Piriyakarnsakul
- Office of National Higher Education Science Research and Innovation Policy Council, Bangkok 10330 Thailand
| | - Muhammad Amin
- Faculty of Geosciences and Civil Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192 Japan
- Faculty of Engineering, Maritim University of Raja Ali Haji, Tanjung Pinang, Kepulauan Riau 29115, Indonesia
| | - Masami Furuuchi
- Faculty of Geosciences and Civil Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192 Japan
- Faculty of Environmental Management, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand
| | - Mitsuhiko Hata
- Faculty of Geosciences and Civil Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192 Japan
| | - Muanfun Inerb
- Faculty of Environmental Management, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand
| | - Worradorn Phairuang
- Faculty of Geosciences and Civil Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192 Japan
- Department of Geography, Faculty of Social Sciences, Chiang Mai University, Muang, Chiang Mai 50200 Thailand
- Corresponding author. Faculty of Geosciences and Civil Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192 Japan.
| |
Collapse
|
8
|
Paraskevopoulou D, Kaskaoutis DG, Grivas G, Bikkina S, Tsagkaraki M, Vrettou IM, Tavernaraki K, Papoutsidaki K, Stavroulas I, Liakakou E, Bougiatioti A, Oikonomou K, Gerasopoulos E, Mihalopoulos N. Brown carbon absorption and radiative effects under intense residential wood burning conditions in Southeastern Europe: New insights into the abundance and absorptivity of methanol-soluble organic aerosols. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 860:160434. [PMID: 36427708 DOI: 10.1016/j.scitotenv.2022.160434] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/04/2022] [Accepted: 11/19/2022] [Indexed: 06/16/2023]
Abstract
Biomass burning is a major source of Brown Carbon (BrC), strongly contributing to radiative forcing. In urban areas of the climate-sensitive Southeastern European region, where strong emissions from residential wood burning (RWB) are reported, radiative impacts of carbonaceous aerosols remain largely unknown. This study examines the absorption properties of water- and methanol-soluble organic carbon (WSOC, MeS_OC) in a city (Ioannina, Greece) heavily impacted by RWB. Measurements were performed during winter (December 2019 - February 2020) and summer (July - August 2019) periods, characterized by RWB and photochemical processing of organic aerosol (OA), respectively. PM2.5 filter extracts were analyzed spectrophotometrically for water- and methanol-soluble BrC (WS_BrC, MeS_BrC) absorption. WSOC concentrations were quantified using TOC analysis, while those of MeS_OC were determined using a newly developed direct quantification protocol, applied for the first time to an extended series of ambient samples. The direct method led to a mean MeS_OC/OC of 0.68 and a more accurate subsequent estimation of absorption efficiencies. The mean winter WS_BrC and MeS_BrC absorptions at 365 nm were 13.9 Mm-1 and 21.9 Mm-1, respectively, suggesting an important fraction of water-insoluble OA. Mean winter WS_BrC and MeS_BrC absorptions were over 10 times those observed in summer. MeS_OC was more absorptive than WSOC in winter (mean mass absorption efficiencies - MAE365: 1.81 vs 1.15 m2 gC-1) and especially in summer (MAE: 1.12 vs 0.27 m2 gC-1) due to photo-dissociation and volatilization of BrC chromophores. The winter radiative forcing (RF) of WS_BrC and MeS_BrC relative to elemental carbon (EC) was estimated at 8.7 % and 16.7 %, respectively, in the 300-2500 nm band. However, those values increased to 48.5 % and 60.2 % at 300-400 nm, indicating that, under intense RWB, BrC forcing becomes comparable to that of soot. The results highlight the consideration of urban BrC emissions in radiative transfer models, as a considerable climate forcing factor.
Collapse
Affiliation(s)
- D Paraskevopoulou
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, P. Penteli, Athens 15236, Greece.
| | - D G Kaskaoutis
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, P. Penteli, Athens 15236, Greece; Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, 70013 Crete, Greece.
| | - G Grivas
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, P. Penteli, Athens 15236, Greece
| | - S Bikkina
- CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004, India
| | - M Tsagkaraki
- Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, 70013 Crete, Greece
| | - I M Vrettou
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, P. Penteli, Athens 15236, Greece
| | - K Tavernaraki
- Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, 70013 Crete, Greece
| | - K Papoutsidaki
- Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, 70013 Crete, Greece
| | - I Stavroulas
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, P. Penteli, Athens 15236, Greece; Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, 70013 Crete, Greece; Climate and Atmosphere Research Center, The Cyprus Institute, 2121 Nicosia, Cyprus
| | - E Liakakou
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, P. Penteli, Athens 15236, Greece
| | - A Bougiatioti
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, P. Penteli, Athens 15236, Greece
| | - K Oikonomou
- Climate and Atmosphere Research Center, The Cyprus Institute, 2121 Nicosia, Cyprus
| | - E Gerasopoulos
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, P. Penteli, Athens 15236, Greece
| | - N Mihalopoulos
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, P. Penteli, Athens 15236, Greece; Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, 70013 Crete, Greece
| |
Collapse
|
9
|
Pani SK, Lin NH, Lee CT, Griffith SM, Chang JHW, Hsu BJ. Insights into aerosol chemical composition and optical properties at Lulin Atmospheric Background Station (2862 m asl) during two contrasting seasons. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 834:155291. [PMID: 35439502 DOI: 10.1016/j.scitotenv.2022.155291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 04/06/2022] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
Continental outflows from peninsular Southeast Asia and East Asia dominate the widespread dispersal of air pollutants over subtropical western North Pacific during spring and autumn, respectively. This study analyses the chemical composition and optical properties of PM10 aerosols during autumn and spring at a representative high-altitude site, viz., Lulin Atmospheric Background Station (23.47°N, 120.87°E; 2862 m a.s.l.), Taiwan. PM10 mass was reconstructed and the contributions of major chemical components were also delineated. Aerosol scattering (σsp) and absorption (σap) coefficients were regressed on mass densities of major chemical components by assuming external mixing between them, and the site-specific mass scattering efficiency (MSE) and mass absorption efficiency (MAE) of individual components for dry conditions were determined. NH4NO3 exhibited the highest MSE among all components during both seasons (8.40 and 12.58 m2 g-1 at 550 nm in autumn and spring, respectively). (NH4)2SO4 and organic matter (OM) accounted for the highest σsp during autumn (51%) and spring (50%), respectively. Mean MAE (mean contribution to σap) of elemental carbon (EC) at 550 nm was 2.51 m2 g-1 (36%) and 7.30 m2 g-1 (61%) in autumn and spring, respectively. Likewise, the mean MAE (mean contribution to σap) of organic carbon (OC) at 550 nm was 0.84 m2 g-1 (64%) and 0.83 m2 g-1 (39%) in autumn and spring, respectively. However, a classification matrix, based on scattering Ångström exponent, absorption Ångström exponent, and single scattering albedo (ω), demonstrated that the composite absorbing aerosols were EC-dominated (with weak absorption; ω = 0.91-0.95) in autumn and a combination of EC-dominated and EC/OC mixture (with moderate absorption; ω = 0.85-0.92) in spring. This study demonstrates a strong link between chemical composition and optical properties of aerosol and provides essential information for model simulations to assess the imbalance in regional radiation budget with better accuracy over the western North Pacific.
Collapse
Affiliation(s)
- Shantanu Kumar Pani
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan.
| | - Neng-Huei Lin
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan; Center for Environmental Monitoring and Technology, National Central University, Taoyuan 32001, Taiwan
| | - Chung-Te Lee
- Graduate Institute of Environmental Engineering, National Central University, Taoyuan 32001, Taiwan.
| | - Stephen M Griffith
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan
| | - Jackson Hian-Wui Chang
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan; Preparatory Center for Science and Technology, University Malaysia Sabah, Kota Kinabalu 88400, Malaysia
| | - Bo-Jun Hsu
- Graduate Institute of Environmental Engineering, National Central University, Taoyuan 32001, Taiwan
| |
Collapse
|
10
|
Pani SK, Lee CT, Griffith SM, Lin NH. Humic-like substances (HULIS) in springtime aerosols at a high-altitude background station in the western North Pacific: Source attribution, abundance, and light-absorption. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 809:151180. [PMID: 34699812 DOI: 10.1016/j.scitotenv.2021.151180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 10/19/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
Atmospheric humic-like substances (HULIS) are important components of biomass-burning (BB) emissions and highly associated with light-absorbing organic aerosols (often referred to as brown carbon). This study highlights the importance of BB-emitted HULIS aerosols in peninsular Southeast Asian outflow to the subtropical western North Pacific. We determined various key light-absorbing characteristics of HULIS i.e. mass absorption cross-section (MACHULIS), absorbing component of the refractive index (kHULIS), and absorption Ångström exponent (AAEHULIS) based on ground-based aerosol light absorption measurements along with HULIS concentrations in springtime aerosols at Lulin Atmospheric Background Station (LABS; 2862 m above mean sea level), which is a representative high-altitude remote site in the western North Pacific. Daily variations of HULIS (0.58-12.92 μg m-3) at LABS were mostly linked with the influence from incoming air-masses, while correlations with BB tracers and secondary aerosols indicated the attribution of primary and secondary sources. Stronger light absorption capability of HULIS was clearly evident from MACHULIS and kHULIS values at 370 nm, which were about ~1.5 times higher during BB-dominated days (1.16 ± 0.75 m2 g-1 and 0.05 ± 0.03, respectively) than that during non-BB days (0.77 ± 0.89 m2 g-1 and 0.03 ± 0.04, respectively). Estimates from a simple radiative transfer model showed that HULIS absorption can add as much as 15.13 W g-1 to atmospheric warming, and ~46% more during BB-dominated than non-BB period, highlighting that HULIS light absorption may significantly affect the Earth-atmosphere system and tropospheric photochemistry over the western North Pacific.
Collapse
Affiliation(s)
- Shantanu Kumar Pani
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan
| | - Chung-Te Lee
- Graduate Institute of Environmental Engineering, National Central University, Taoyuan 32001, Taiwan; Center for Environmental Monitoring and Technology, National Central University, Taoyuan 32001, Taiwan
| | - Stephen M Griffith
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan
| | - Neng-Huei Lin
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan; Center for Environmental Monitoring and Technology, National Central University, Taoyuan 32001, Taiwan.
| |
Collapse
|
11
|
Organic and Elemental Carbon in the Urban Background in an Eastern Mediterranean City. ATMOSPHERE 2022. [DOI: 10.3390/atmos13020197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Mediterranean region is an important area for air pollution as it is the crossroads between three continents; therefore, the concentrations of atmospheric aerosol particles are influenced by emissions from Africa, Asia, and Europe. Here we concentrate on an eleven-month time series of the ambient concentration of organic carbon (OC) and elemental carbon (EC) between May 2018–March 2019 in Amman, Jordan. Such a dataset is unique in Jordan. The results show that the OC and EC annual mean concentrations in PM2.5 samples were 5.9 ± 2.8 µg m–3 and 1.7 ± 1.1 µg m–3, respectively. It was found that the majority of OC and EC concentrations were within the fine particle fraction (PM2.5). During sand and dust storm (SDS) episodes OC and EC concentrations were higher than the annual means; the mean values during these periods were about 9.6 ± 3.5 µg m–3 and 2.5 ± 1.2 µg m–3 in the PM2.5 samples. Based on this, the SDS episodes were identified to be responsible for an increased carbonaceous aerosol content as well as PM2.5 and PM10 content, which may have direct implications on human health. This study encourages us to perform more extensive measurements during a longer time period and to include an advanced chemical and physical characterization for urban aerosols in the urban atmosphere of Amman, which can be representative of other urban areas in the region.
Collapse
|
12
|
Kaskaoutis DG, Grivas G, Stavroulas I, Bougiatioti A, Liakakou E, Dumka UC, Gerasopoulos E, Mihalopoulos N. Apportionment of black and brown carbon spectral absorption sources in the urban environment of Athens, Greece, during winter. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 801:149739. [PMID: 34467915 DOI: 10.1016/j.scitotenv.2021.149739] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/30/2021] [Accepted: 08/13/2021] [Indexed: 06/13/2023]
Abstract
This study examines the spectral properties and source characteristics of absorbing aerosols (BC: Black Carbon; BrC: Brown Carbon, based on aethalometer measurements) in the urban background of Athens during December 2016-February 2017. Using common assumptions regarding the spectral dependence of absorption due to BC (AAEBC = 1) and biomass burning (AAEbb = 2), and calculating an optimal AAEff value for the dataset (1.18), the total spectral absorption was decomposed into five components, corresponding to absorption of BC and BrC from fossil-fuel (ff) combustion and biomass burning (bb), and to secondary BrC estimated using the BC-tracer minimum R-squared (MRS) method. Substantial differences in the contribution of various components to the total absorption were found between day and night, due to differences in emissions and meteorological dynamics, while BrC and biomass burning aerosols presented higher contributions at shorter wavelengths. At 370 nm, the absorption due to BCff contributed 36.3% on average, exhibiting a higher fraction (58.1%) during daytime, while the mean BCbb absorption was estimated at 18.4%. The mean absorption contributions due to BrCff, BrCbb and BrCsec were 6.7%, 32.3% and 4.9%, respectively. The AbsBCff,370 component maximized during the morning traffic hours and was strongly correlated with NOx (R2 = 0.76) and CO (R2 = 0.77), while a similar behavior was seen for the AbsBrCff,370 component. AbsBCbb and AbsBrCbb levels escalated during nighttime and were highly associated with nss-K+ and with the organic aerosol (OA) components related to fresh and fast-oxidized biomass burning (BBOA and SV-OOA) as obtained from ACSM measurements. Multiple linear regression was used to attribute BrC absorption to five OA components and to determine their absorption contributions and efficiencies, revealing maximum contributions of BBOA (33%) and SV-OOA (21%). Sensitivity analysis was performed in view of the methodological uncertainties and supported the reliability of the results, which can have important implications for radiative transfer models.
Collapse
Affiliation(s)
- D G Kaskaoutis
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece; Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital 263 001, India.
| | - G Grivas
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece.
| | - I Stavroulas
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece
| | - A Bougiatioti
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece
| | - E Liakakou
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece
| | - U C Dumka
- Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, 71003 Crete, Greece
| | - E Gerasopoulos
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece
| | - N Mihalopoulos
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece; Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital 263 001, India
| |
Collapse
|
13
|
Zhu C, Miyakawa T, Irie H, Choi Y, Taketani F, Kanaya Y. Light-absorption properties of brown carbon aerosols in the Asian outflow: Implications of a combination of filter and ground remote-sensing observations at Fukue Island, Japan. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 797:149155. [PMID: 34346377 DOI: 10.1016/j.scitotenv.2021.149155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 06/13/2023]
Abstract
Brown carbon (BrC) aerosols have important warming effects on Earth's radiative forcing. However, information on the evolution of the light-absorption properties of BrC aerosols in the Asian outflow region is limited. In this study, we evaluated the light-absorption properties of BrC using in-situ filter measurements and sky radiometer observations of the ground-based remote sensing network SKYradiometer NETwork (SKYNET) made on Fukue Island, western Japan in 2018. The light-absorption coefficient of BrC obtained from filter measurements had a temporal trend similar to that of the ambient concentration of black carbon (BC), indicating that BrC and BC have common combustion sources. The absorption Angstrom exponent in the wavelength range of 340-870 nm derived from the SKYNET observations was 15% higher in spring (1.81 ± 0.30) than through the whole year (1.53 ± 0.50), suggesting that the Asian outflow carries light-absorbing aerosols to Fukue Island and the western North Pacific. After eliminating the contributions of BC, the absorption Angstrom exponent of BrC alone obtained from filter observations had a positive Spearman correlation (rs = 0.77, p < 0.1) with that derived from SKYNET observations but 33% higher values, indicating that the light-absorption properties of BrC were successfully captured using the two methods. Using the atmospheric transport model FLEXPART and fire hotspots obtained from the Visible Infrared Imaging Radiometer Suite product, we identified a high-BrC event related to an air mass originating from regions with consistent fossil fuel combustion and sporadic open biomass burning in central East China. The results of the study may help to clarify the dynamics and climatic effects of BrC aerosols in East Asia.
Collapse
Affiliation(s)
- Chunmao Zhu
- Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama 2360001, Japan.
| | - Takuma Miyakawa
- Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama 2360001, Japan
| | - Hitoshi Irie
- Center for Environmental Remote Sensing, Chiba University, Chiba 2638522, Japan
| | - Yongjoo Choi
- Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama 2360001, Japan
| | - Fumikazu Taketani
- Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama 2360001, Japan
| | - Yugo Kanaya
- Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama 2360001, Japan
| |
Collapse
|
14
|
Evaluation of Machine Learning Models for Estimating PM2.5 Concentrations across Malaysia. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11167326] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Southeast Asia (SEA) is a hotspot region for atmospheric pollution and haze conditions, due to extensive forest, agricultural and peat fires. This study aims to estimate the PM2.5 concentrations across Malaysia using machine-learning (ML) models like Random Forest (RF) and Support Vector Regression (SVR), based on satellite AOD (aerosol optical depth) observations, ground measured air pollutants (NO2, SO2, CO, O3) and meteorological parameters (air temperature, relative humidity, wind speed and direction). The estimated PM2.5 concentrations for a two-year period (2018–2019) are evaluated against measurements performed at 65 air-quality monitoring stations located at urban, industrial, suburban and rural sites. PM2.5 concentrations varied widely between the stations, with higher values (mean of 24.2 ± 21.6 µg m−3) at urban/industrial stations and lower (mean of 21.3 ± 18.4 µg m−3) at suburban/rural sites. Furthermore, pronounced seasonal variability in PM2.5 is recorded across Malaysia, with highest concentrations during the dry season (June–September). Seven models were developed for PM2.5 predictions, i.e., separately for urban/industrial and suburban/rural sites, for the four dominant seasons (dry, wet and two inter-monsoon), and an overall model, which displayed accuracies in the order of R2 = 0.46–0.76. The validation analysis reveals that the RF model (R2 = 0.53–0.76) exhibits slightly better performance than SVR, except for the overall model. This is the first study conducted in Malaysia for PM2.5 estimations at a national scale combining satellite aerosol retrievals with ground-based pollutants, meteorological factors and ML techniques. The satisfactory prediction of PM2.5 concentrations across Malaysia allows a continuous monitoring of the pollution levels at remote areas with absence of measurement networks.
Collapse
|
15
|
Modeling Investigation of Brown Carbon Aerosol and Its Light Absorption in China. ATMOSPHERE 2021. [DOI: 10.3390/atmos12070892] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Brown carbon (BrC) is a type of organic carbon with light-absorbing abilities, especially in ultraviolet (UV) radiation, which could significantly contribute to global warming. Observations have shown high BrC concentrations and absorption in China, suggesting potentially large BrC emissions. The potential contribution of fossil fuel combustion to BrC emission has been ignored in most previous studies. Here, we use GEOS-Chem to simulate BrC distribution and absorption in China, accounting for three major primary BrC sources: residential coal and biofuel combustion, vehicle exhausts, and open biomass burning. Based on the literature and related energy consumption data, we estimate the specific emission ratio of BrC versus BC, and BrC mass absorption efficiency (MAE) for each source. Combined with BC emission, total BrC emission in China is then estimated to be 3.42 Tg yr−1 in 2018, of which 71% is from residential combustion, 14% is from vehicle exhaust, and 15% is from open biomass burning. Residential combustion is the main source of surface BrC in China, accounting for 60% on average, followed by open biomass burning (23%) and vehicle exhaust emissions (17%). There is a clear seasonality in surface BrC concentrations with the maximum in winter (5.1 µg m−3), followed by spring (2.8 µg m−3), autumn (2.3 µg m−3), and summer (1.3 µg m−3). BrC AAOD at 365 nm ranges from 0.0017 to 0.060 in China, mainly dominated by residential combustion (73%), followed by open biomass burning (16%), and vehicle exhaust emissions (11%). It is also estimated that BrC accounts for 45–67% (52% on average) of total carbonaceous aerosol AAOD at 365 nm, implying an equal importance of BrC and BC regarding the absorption in UV radiation.
Collapse
|