Sources of Wintertime Atmospheric Organic Pollutants in a Large Canadian City: Insights from Particle and Gas Phase Measurements

ACS ES&T Air, Journal Year: 2024, Volume and Issue: 1(7), P. 690 - 703

Published: May 3, 2024

Although atmospheric organic pollutants have been extensively studied to elucidate summertime urban photochemical air pollution, uncertainties remain concerning the quality of wintertime in large northern North American cities. Here, we used online mass spectrometric measurements volatile compounds (VOCs) and aerosol (OA), combined with positive matrix factorization (PMF), identify sources downtown Toronto, Canada during February–March 2023. In some cases, comparable PMF factors were identified for both VOCs OA, such as from traffic, cooking, background oxygenated sources. However, VOC yielded additional information, a factor associated human-related emissions VOCs. Additionally, yields two traffic factors: one likely related gasoline diesel use. Despite cold relatively dark conditions, OA grow intensity daytime, indicative activity, whereas cooking enhanced morning late evening due timing vehicle use, boundary layer effects. This study illustrates benefits that arise parallel source–receptor analyses gases particles.

Language: Английский

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Changes in sources and formation mechanisms of carbonaceous aerosols driven by short-term air pollution controls in Megacity Xi'an, China

Atmospheric Environment, Journal Year: 2024, Volume and Issue: 322, P. 120369 - 120369

Published: Jan. 26, 2024

Language: Английский

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Formation of Ozone and PM_2.5 in Smoke from Prescribed Burning in the Southeastern United States

ACS ES&T Air, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 28, 2025

Language: Английский

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Formation of highly absorptive secondary brown carbon through nighttime multiphase chemistry of biomass burning emissions

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(6), P. 3737 - 3752

Published: March 28, 2025

Abstract. Biomass burning is a major global source of both primary brown carbon (BrC) and reactive trace gases in the atmosphere thus has significant impact on climate regional atmospheric chemistry. However, substantial gap remains our understanding nighttime evolution biomass emissions. Here we present prominent formation secondary organic aerosol (Night-OA) with strong absorptivity but markedly different spectral dependence from that aerosols, which was observed during autumn Pearl River Delta region China when plumes prevailed. Our results demonstrate Night-OA appeared to have high magnitudes emissions at nightfall available oxidants NO2 O3. Active NO3 radical chemistry characterized by quick O3 depletion almost zero concentration NO. The rapid decrease coincident nitrate suggests consumption supplied N2O5 reaction chains. quickest occurred ceased relative humidity reached maximum, it mainly added mass water-abundant diameter ranges. This co-variation gas-phase reactions precursors, along aqueous-phase involving preexisting hygroscopic aerosols diluted plume, likely work concert promote Night-OA. Preexisting background are generally much more than directly emitted burning. Incorporating important role aging would be valuable future laboratory model simulation studies. proposed mechanisms for BrC broad implications air quality impacts burning, including interaction between humid regions, as well pyroconvection clouds.

Language: Английский

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Chemical evolution of primary and secondary biomass burning aerosols during daytime and nighttime

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(13), P. 7461 - 7477

Published: July 10, 2023

Abstract. Primary emissions from wood and pellet stoves were aged in an atmospheric simulation chamber under daytime nighttime conditions. The aerosol was analyzed with online mass spectrometry offline Fourier transform infrared spectroscopy (FTIR). Measurements using the two techniques agreed reasonably well terms of organic (OA) concentration, OA:OC trends, concentrations biomass burning markers – lignin-like compounds anhydrosugars. Based on spectrometry, around 15 % primary (POA) underwent some form transformation during oxidation conditions after 6–10 h exposure. A lesser extent observed oxidation. decay certain semi-volatile (e.g., levoglucosan) less volatile lignin-like) POA components substantial aging, highlighting role heterogeneous reactions gas–particle partitioning. Lignin-like to degrade both conditions, whereas anhydrosugars degraded only Among marker fragments OA (bbPOA), heavy ones (higher m/z) relatively more stable aging. secondary (bbSOA) became oxidized continued aging resembled that aerosols. bbSOA formed dominated by acids. Organonitrates important product humid dry Our results underline importance changes aerosols their Heavier seldom used chemistry can be as tracers bbPOA and, combination established levoglucosan marker, provide indication

Language: Английский

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Insights into secondary organic aerosol formation from the day- and nighttime oxidation of polycyclic aromatic hydrocarbons and furans in an oxidation flow reactor

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(23), P. 15077 - 15096

Published: Dec. 7, 2023

Abstract. Secondary organic aerosols (SOAs) formed by oxidation of typical precursors largely emitted biomass burning, such as polycyclic aromatic hydrocarbons (PAHs) and furans, are still poorly characterized. We evaluated compared the formation yields, effective density (ρeff), absorption Ångström exponent (α), mass coefficient (MAC) laboratory-generated SOAs from three furan compounds four PAHs. were generated in an flow reactor under day- (OH radicals) or nighttime (NO3 conditions. The ρeff, α, MAC varied depending on precursor oxidant considered. ρeff with OH NO3 tended to increase particle size before reaching a “plateau”, highlighting potential differences SOA chemical composition and/or morphology, according size. Three times lower yields obtained OH. PAH (18 %–76 %) five six higher than those for furans (3 %–12 %). While showed low negligible light properties, had significant impact UV–visible region, implying contribution atmospheric brown carbon. No values was observed processes, probably due nitrogen-containing chromophores only (without NOx). results demonstrated that PAHs through both, have substantial aerosol properties.

Language: Английский

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Characterization and dark oxidation of the emissions of a pellet stove

Environmental Science Atmospheres, Journal Year: 2023, Volume and Issue: 3(9), P. 1319 - 1334

Published: Jan. 1, 2023

Pellet combustion in residential heating stoves has increased globally during the last decade. Despite their high efficiency, widespread use of pellet is expected to adversely impact air quality. The atmospheric aging emissions received even less attention, focusing mainly on daytime conditions, while degree which undergo night-time as well role relative humidity remain poorly understood. In this study, environmental simulation chamber experiments were performed characterize fresh and aged organic aerosol (OA) emitted by a stove. stove PM1 (particulate matter with an aerodynamic diameter than 1 μm) consisted OA (93 ± 4%, mean standard deviation) black carbon (5 3%). primary (POA) oxygen-to-carbon ratio (O : C) was 0.58 0.04, higher that logwood emissions. at concentration 70 μg m-3 (after dilution equilibration chamber) semi-volatile (68%), low extremely volatility (16%) intermediate-volatility compounds. oxidation under dark conditions investigated injecting nitrogen dioxide (NO2) ozone (O3) into chamber, different (10-80%) (RH) levels. all secondary (SOA) formation observed, increasing levels after few hours exposure NO3 radicals. change composition extent depended RH. For RH, SOA mass formed up 30% initial OA, accompanied moderate both O C (7-8% increase) spectrum. Aging RH (60-80%) led more oxygenated (increase 11-18%), but only minor (1-10%) increase mass. indicates importance heterogeneous aqueous reactions system, oxidize original relatively small net These results show can chemically evolve photochemical activity (e.g. wintertime period) important enhancement certain conditions.

Language: Английский

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A coupled atmospheric simulation chamber system for the production of realistic aerosols and preclinical model exposure

Air Quality Atmosphere & Health, Journal Year: 2024, Volume and Issue: unknown

Published: July 18, 2024

Language: Английский

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Influence of relative humidity and aging on the optical properties of organic aerosols from burning African biomass fuels

Aerosol Science and Technology, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 23

Published: Oct. 11, 2024

Biomass burning (BB) is a major source of atmospheric fine carbonaceous aerosols, which play significant, yet uncertain, role in modulating the Earth's radiation balance. However, accurately representing their optical properties climate models remains challenging due to factors such as particle size, mixing state, combustion type, chemical composition, aging processes, and relative humidity (RH). In our study, we investigated BB organic-rich aerosols generated from smoldering sub-Saharan African biomass fuels. Fuel samples were collected Africa laboratory. We quantified key parameters, including mass cross-sections for extinction (2.04 ± 0.32 − 15.5 2.48 m2/g), absorption (0.04 0.01–0.3 0.1 scattering (1.9 0.68–15.3 5.5 m2/g). Wavelength-dependent used determine Ångström exponents. The single albedo these ranged 0.8 0.03 1.0 0.04 observed wavelength-dependent behavior. Extinction emission determined at wavelength 550 nm, with values ranging 42 5 293 32 m2/kg. Notably, exhibited fuel-type dependence, differences between hardwood other fuels, grass animal dung. Aging increased while had opposite effect across all Nitrate radical oxidation, both photo dark conditions, also influenced properties. findings are expected close gap understanding aerosol emissions one least studied regions world – providing information air quality region.

Language: Английский

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Simulation of the influence of residential biomass burning on air quality in an urban area

Atmospheric Environment, Journal Year: 2023, Volume and Issue: 309, P. 119897 - 119897

Published: June 9, 2023

Language: Английский

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