Effects of Anthropogenic and Biogenic Volatile Organic Compounds on Los Angeles Air Quality

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(18), P. 12191 - 12201

Published: Sept. 8, 2021

Assessing the role of volatile organic compounds (VOCs) in production ozone and secondary aerosol (SOA) is especially important light ongoing policy goals. Here, we estimated formation potential (OFP) SOA (SOAP) anthropogenic biogenic VOC emissions to evaluate (1) VOCs associated sectors that dominate OFP SOAP (2) impacts enhanced from urban greening programs on air quality Los Angeles county. In present-day scenario, ethylene had largest followed by m & p-xylene, toluene, propylene, formaldehyde. The top five contributors were mineral spirits, benzene, heptadecane, hexadecane. Mobile solvent sources dominant for both SOAP. increases due future significant effects offset benefits reducing emissions. This study demonstrates county, likely other cities as well, need account contributions pollution, should consider using vegetation types with low avoid further degradation quality.

Language: Английский

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Spatial Distribution of Secondary Organic Aerosol Formation Potential in China Derived from Speciated Anthropogenic Volatile Organic Compound Emissions

Environmental Science & Technology, Journal Year: 2018, Volume and Issue: 52(15), P. 8146 - 8156

Published: June 28, 2018

Fine particulate matter (PM2.5), largely composed of secondary organic aerosol (SOA), is currently one the most intractable environmental problems in China. As crucial precursors for SOA, understanding formation propensity various volatile compound (VOC) species and sources useful pollution control. In this work, we estimated SOA potential (SOAP) anthropogenic VOC emissions based on an improved speciated emission inventory investigated its distribution According to our estimates, toluene had largest SOAP, followed by n-dodecane, m-/p-xylene, styrene, n-decane, n-undecane, while passenger cars, chemical fiber manufacturing, asphalt paving, building coating were top five SOAP-contributing nationwide. The spatial SOAP China shows a distinct pattern high values southeast low northwest. Beijing–Tianjin–Hebei surroundings, Yangtze River Delta, Pearl Sichuan–Chongqing District found have highest particularly urban areas. major differed among these regions, which was attributed local industrial energy structures. Our results suggest that mitigate PM2.5 China, more efficient SOAP-based control measures should be implemented instead current emissions-based policies, strategies adapted conditions.

Language: Английский

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Size-dependent influence of NO _x on the growth rates of organic aerosol particles

Science Advances, Journal Year: 2020, Volume and Issue: 6(22)

Published: May 27, 2020

NO x is important for particle growth as it can participate in HOM formation and alter the volatility distribution.

Language: Английский

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Impact of NO<sub><i>x</i></sub> on secondary organic aerosol (SOA) formation from <i>α</i>-pinene and <i>β</i>-pinene photooxidation: the role of highly oxygenated organic nitrates

Atmospheric chemistry and physics, Journal Year: 2020, Volume and Issue: 20(17), P. 10125 - 10147

Published: Sept. 1, 2020

Abstract. The formation of organic nitrates (ONs) in the gas phase and their impact on mass secondary aerosol (SOA) was investigated a laboratory study for α-pinene β-pinene photooxidation. Focus elucidation those mechanisms that cause often observed suppression SOA by NOx, therein role highly oxygenated multifunctional molecules (HOMs). We with increasing NOx concentration (a) portion HOM (HOM-ONs) increased, (b) fraction accretion products (HOM-ACCs) decreased, (c) HOM-ACCs contained average smaller carbon numbers. Specifically, we (HOM-ONs), arising from termination reactions peroxy radicals permutation (HOM-PPs), such as ketones, alcohols, or hydroperoxides, formed other reactions. Effective uptake coefficients γeff HOMs particles were determined. more than six O atoms efficiently condensed (γeff>0.5 average), containing eight atoms, every collision led to loss. There no systematic difference HOM-ONs HOM-PPs same radicals. This similarity is attributed character HOMs: functional groups precursor radical are identical, vapor pressures should not strongly depend final group. As consequence, suppressing effect cannot be simply explained replacement terminal nitrate groups. According all will contribute bound (OrgNO3) particulate phase. However, OrgNO3 stored condensable molecular masses > 230 Da appeared substantially higher spectrometry. result suggests losses particles, probably due hydrolysis releases HNO3 into but leaves behind rest loss alone could explain particle β-pinene. Instead can attribute most reduction yields significant HOM-ACCs, which have high potentially important at low-NOx conditions.

Language: Английский

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SOA and gas phase organic acid yields from the sequential photooxidation of seven monoterpenes

Atmospheric Environment, Journal Year: 2018, Volume and Issue: 187, P. 335 - 345

Published: June 6, 2018

We investigate secondary organic aerosol (SOA) and gas phase acid yields from the sequential photooxidation of seven monoterpene isomers (α-pinene, β-pinene, limonene, sabinene, terpinolene, α-terpinene, γ-terpinene) using an Oxidative Flow Reactor under dry conditions. SOA were highest for terpinolene (33% at 5.7 days aging), followed by α-pinene, γ-terpinene, α-terpinene. Isomers with exocyclic double bonds (i.e. immediately adjacent to a ring) had higher than those endocyclic bonds, or that are unattached ring structure. increased OH exposure, highlighting limitation single values yield in modeling studies, need isomer-specific parameterizations. adequately fit one-product model broad agreement previous studies. linearly mass concentration, possibly result high loading short residence times flow reactor. Gas formic, acetic, butyric, methacrylic (or their isomers) very different patterns as function exposure yields, poorly correlated rate constants. These observations suggest volatility (fragmentation) products produced lost on timescales production condensation lower-volatility (functionalization) products. Formic ranged 0.06 9.3% across all exposures. γ-terpinene (0.36–3%) monotonically unlike other isomers, which exhibited initial increases formic decreases concentrations. This difference trends is consistent distribution carbon-containing species identified chemical ionization spectrometry.

Language: Английский

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Significant source of secondary aerosol: formation from gasoline evaporative emissions in the presence of SO<sub>2</sub> and NH<sub>3</sub>

Atmospheric chemistry and physics, Journal Year: 2019, Volume and Issue: 19(12), P. 8063 - 8081

Published: June 20, 2019

Abstract. Gasoline evaporative emissions have become an important anthropogenic source of urban atmospheric volatile organic compounds (VOCs) and secondary aerosol (SOA). These a significant impact on regional air quality, especially in China where car ownership is growing rapidly. However, the contribution to (SA) not clear pollution complex which high concentration SO2 NH3 was present. In this study, effects SA formation from unburned gasoline vapor were investigated 30 m3 indoor smog chamber. It found that increase concentrations (0–151 0–200 ppb, respectively) could linearly promote SA, be enhanced by factor 1.6–2.6 2.0–2.5, respectively. Sulfate most sensitive concentration, followed aerosol, due only acid catalytic effect, but also related sulfur-containing compounds. case increasing ammonium nitrate increased more significantly than nitrogen-containing organics enhanced, as revealed results positive matrix factorization (PMF) analysis. New particle (NPF) size growth presence NH3. This work indicates will Meanwhile, these might potential sulfur- organics. Our provides scientific basis for synergistic emission reduction precursors, including NOx, SO2, NH3, particularly VOCs, mitigate particulate matter (PM) China.

Language: Английский

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Smog chamber study of the effects of NOx and NH3 on the formation of secondary organic aerosols and optical properties from photo-oxidation of toluene

The Science of The Total Environment, Journal Year: 2020, Volume and Issue: 727, P. 138632 - 138632

Published: April 14, 2020

Language: Английский

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Effects of NO and SO2 on the secondary organic aerosol formation from the photooxidation of 1,3,5-trimethylbenzene: A new source of organosulfates

Environmental Pollution, Journal Year: 2020, Volume and Issue: 264, P. 114742 - 114742

Published: May 5, 2020

Language: Английский

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Highly Oxygenated Organic Nitrates Formed from NO₃ Radical-Initiated Oxidation of β-Pinene

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(23), P. 15658 - 15671

Published: Nov. 22, 2021

The reactions of biogenic volatile organic compounds (BVOC) with the nitrate radicals (NO3) are major night-time sources nitrates and secondary aerosols (SOA) in regions influenced by BVOC anthropogenic emissions. In this study, formation gas-phase highly oxygenated molecules-organic (HOM-ON) from NO3-initiated oxidation a representative monoterpene, β-pinene, was investigated SAPHIR chamber (Simulation Atmosphere PHotochemistry large Reaction chamber). Six monomer (C = 7–10, N 1–2, O 6–16) five accretion product 17–20, 2–4, 9–22) families were identified further classified into first- or second-generation products based on their temporal behavior. time lag observed peak concentrations between peroxy containing odd even number oxygen atoms, as well corresponding termination products, provided constraints HOM-ON mechanism. can be explained unimolecular bimolecular radicals. A dominant portion carbonylnitrates detected, highlighting significance intramolecular H-shift for HOM-ON. mean molar yield estimated to 4.8% (−2.6%/+5.6%), suggesting significant contributions SOA formation.

Language: Английский

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Highly oxygenated organic molecule (HOM) formation in the isoprene oxidation by NO<sub>3</sub> radical

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(12), P. 9681 - 9704

Published: June 29, 2021

Abstract. Highly oxygenated organic molecules (HOM) are found to play an important role in the formation and growth of secondary aerosol (SOA). SOA is type with significant impact on air quality climate. Compared oxidation volatile compounds by ozone (O3) hydroxyl radical (OH), HOM nitrate (NO3), oxidant at nighttime dawn, has received less attention. In this study, reaction isoprene NO3 was investigated SAPHIR chamber (Simulation Atmospheric PHotochemistry a large Reaction chamber). A number HOM, including monomers (C5), dimers (C10), trimers (C15), both closed-shell open-shell peroxy radicals (RO2), were identified classified into various series according their formula. Their pathways proposed based observed known mechanisms literature, which further constrained time profiles after sequential addition differentiate first- second-generation products. containing one three N atoms (1–3N-monomers) formed, starting carbon double bond, forming radicals, followed autoxidation. 1N-monomers formed direct first-generation 2N-monomers (e.g., C5H8N2On(n=7–13), C5H10N2On(n=8–14)) likely termination products C5H9N2On⚫, C5-hydroxynitrate (C5H9NO4), product bond. 2N-monomers, products, dominated accounted for ∼34 % all indicating + under our experimental conditions. H shift alkoxy form subsequent autoxidation (“alkoxy–peroxy” pathway) be pathway formation. mostly accretion monomer RO2 via reactions dimer possibly C5–RO2 isoprene. RO2. The concentrations different showed distinct during reaction, linked pathway. either typical profile or combination both, multiple and/or isomers. Total molar yield estimated 1.2 %-0.7%+1.3%, corresponded ∼3.6 assuming molecular weight C5H9NO6 as lower limit. This suggests that may contribute fraction NO3.

Language: Английский

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