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Moschos V, Christensen C, Mouton M, Fiddler MN, Isolabella T, Mazzei F, Massabò D, Turpin BJ, Bililign S, Surratt JD. Quantifying the Light-Absorption Properties and Molecular Composition of Brown Carbon Aerosol from Sub-Saharan African Biomass Combustion. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:4268-4280. [PMID: 38393751 PMCID: PMC10919089 DOI: 10.1021/acs.est.3c09378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 02/25/2024]
Abstract
Sub-Saharan Africa is a hotspot for biomass burning (BB)-derived carbonaceous aerosols, including light-absorbing organic (brown) carbon (BrC). However, the chemically complex nature of BrC in BB aerosols from this region is not fully understood. We generated smoke in a chamber through smoldering combustion of common sub-Saharan African biomass fuels (hardwoods, cow dung, savanna grass, and leaves). We quantified aethalometer-based, real-time light-absorption properties of BrC-containing organic-rich BB aerosols, accounting for variations in wavelength, fuel type, relative humidity, and photochemical aging conditions. In filter samples collected from the chamber and Botswana in the winter, we identified 182 BrC species, classified into lignin pyrolysis products, nitroaromatics, coumarins, stilbenes, and flavonoids. Using an extensive set of standards, we determined species-specific mass and emission factors. Our analysis revealed a linear relationship between the combined BrC species contribution to chamber-measured BB aerosol mass (0.4-14%) and the mass-absorption cross-section at 370 nm (0.2-2.2 m2 g-1). Hierarchical clustering resolved key molecular-level components from the BrC matrix, with photochemically aged emissions from leaf and cow-dung burning showing BrC fingerprints similar to those found in Botswana aerosols. These quantitative findings could potentially help refine climate model predictions, aid in source apportionment, and inform effective air quality management policies for human health and the global climate.
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Affiliation(s)
- Vaios Moschos
- Department
of Physics, College of Science and Technology, North Carolina A&T State University, Greensboro, North Carolina 27411, United States
- Department
of Environmental Sciences and Engineering, Gillings School of Global
Public Health, The University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27516, United States
| | - Cade Christensen
- Department
of Chemistry, College of Arts and Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Megan Mouton
- Department
of Applied Sciences and Technology, College of Science and Technology, North Carolina A&T State University, Greensboro, North Carolina 27411, United States
| | - Marc N. Fiddler
- Department
of Chemistry, College of Science and Technology, North Carolina A&T State University, Greensboro, North Carolina 27411, United States
| | - Tommaso Isolabella
- Department
of Physics, University of Genoa, 16146 Genoa, Italy
- National
Institute of Nuclear Physics (INFN), 16146 Genoa, Italy
| | - Federico Mazzei
- Department
of Physics, University of Genoa, 16146 Genoa, Italy
| | - Dario Massabò
- Department
of Physics, University of Genoa, 16146 Genoa, Italy
| | - Barbara J. Turpin
- Department
of Environmental Sciences and Engineering, Gillings School of Global
Public Health, The University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27516, United States
| | - Solomon Bililign
- Department
of Physics, College of Science and Technology, North Carolina A&T State University, Greensboro, North Carolina 27411, United States
- Department
of Applied Sciences and Technology, College of Science and Technology, North Carolina A&T State University, Greensboro, North Carolina 27411, United States
| | - Jason D. Surratt
- Department
of Environmental Sciences and Engineering, Gillings School of Global
Public Health, The University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27516, United States
- Department
of Chemistry, College of Arts and Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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Humes M, Machesky JE, Kim S, Oladeji OJ, Gentner DR, Donahue NM, Presto AA. Primary and Secondary Organic Aerosol Formation from Asphalt Pavements. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:20034-20042. [PMID: 37931038 PMCID: PMC10702534 DOI: 10.1021/acs.est.3c06037] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 10/19/2023] [Accepted: 10/20/2023] [Indexed: 11/08/2023]
Abstract
Asphalt is ubiquitous across cities and a source of organic compounds spanning a wide range of volatility and may be an overlooked source of urban organic aerosols. The emission rate and composition depend strongly on temperature, but emissions have been observed at both application temperatures and surface temperatures during warm sunny days. Here we report primary organic aerosol (POA) emissions and secondary organic aerosol (SOA) production from asphalt. We reheated real-world asphalt samples to application-relevant temperatures (∼130 °C) and typical summertime road-surface temperatures (∼55 °C) and then flushed the emitted vapors into an environmental oxidation chamber containing ammonium sulfate seed particles. SOA was then formed following the photo-oxidation of emissions under high-NOx conditions typical of urban atmospheres. We find that POA only forms at application temperature as it does not require further oxidation, whereas SOA forms under both conditions; with the resulting POA and SOA both being semi-volatile. While total OA formation rates were substantially greater under the limited time spent under application conditions, SOA formation from passive asphalt heating presents a potential long-term source, as heating continues for the lifetime of the road surface. This suggests that persistent asphalt solar heating is likely a considerable and continued source of summertime SOA in urban environments.
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Affiliation(s)
- Mackenzie
B. Humes
- Department
of Chemical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Jo E. Machesky
- Department
of Chemical & Environmental Engineering, Yale University, New Haven, Connecticut 06511, United States
| | - Sunhye Kim
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Oladayo J. Oladeji
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
| | - Drew R. Gentner
- Department
of Chemical & Environmental Engineering, Yale University, New Haven, Connecticut 06511, United States
| | - Neil M. Donahue
- Department
of Chemical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Albert A. Presto
- Department
of Mechanical Engineering, Carnegie Mellon
University, Pittsburgh, Pennsylvania 15213, United States
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Sasidharan S, He Y, Akherati A, Li Q, Li W, Cocker D, McDonald BC, Coggon MM, Seltzer KM, Pye HOT, Pierce JR, Jathar SH. Secondary Organic Aerosol Formation from Volatile Chemical Product Emissions: Model Parameters and Contributions to Anthropogenic Aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:11891-11902. [PMID: 37527511 DOI: 10.1021/acs.est.3c00683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
Volatile chemical products (VCP) are an increasingly important source of hydrocarbon and oxygenated volatile organic compound (OVOC) emissions to the atmosphere, and these emissions are likely to play an important role as anthropogenic precursors for secondary organic aerosol (SOA). While the SOA from VCP hydrocarbons is often accounted for in models, the formation, evolution, and properties of SOA from VCP OVOCs remain uncertain. We use environmental chamber data and a kinetic model to develop SOA parameters for 10 OVOCs representing glycols, glycol ethers, esters, oxygenated aromatics, and amines. Model simulations suggest that the SOA mass yields for these OVOCs are of the same magnitude as widely studied SOA precursors (e.g., long-chain alkanes, monoterpenes, and single-ring aromatics), and these yields exhibit a linear correlation with the carbon number of the precursor. When combined with emissions inventories for two megacities in the United States (US) and a US-wide inventory, we find that VCP VOCs react with OH to form 0.8-2.5× as much SOA, by mass, as mobile sources. Hydrocarbons (terpenes, branched and cyclic alkanes) and OVOCs (terpenoids, glycols, glycol ethers) make up 60-75 and 25-40% of the SOA arising from VCP use, respectively. This work contributes to the growing body of knowledge focused on studying VCP VOC contributions to urban air pollution.
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Affiliation(s)
- Sreejith Sasidharan
- Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Yicong He
- Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Ali Akherati
- Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Qi Li
- Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92521, United States
| | - Weihua Li
- Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92521, United States
| | - David Cocker
- Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92521, United States
| | - Brian C McDonald
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Matthew M Coggon
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Karl M Seltzer
- Office of Air and Radiation, Environmental Protection Agency, Research Triangle Park, North Carolina 27709, United States
| | - Havala O T Pye
- Office of Research and Development, Environmental Protection Agency, Research Triangle Park, North Carolina 27709, United States
| | - Jeffrey R Pierce
- Atmospheric Science, Colorado State University, Fort Collins, Colorado 80521, United States
| | - Shantanu H Jathar
- Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
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