Multiphase Processing of the Water-Soluble and Insoluble Phases of Biomass Burning Organic Aerosol

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

Published: March 31, 2025

Biomass burning is one of the most significant sources organic aerosol in atmosphere. (BBOA) has been observed to undergo liquid–liquid phase separation (LLPS) give core–shell morphology with hydrophobic encapsulating hydrophilic phase, potentially impacting evolution light-absorbing components, i.e., brown carbon (BrC), through multiphase processes. Here, we demonstrate how processing differs between water-soluble (i.e., hydrophilic) and insoluble hydrophobic) phases BBOA terms reactive uptake ozone a coated-wall flow tube. Effects relative humidity (RH) ultraviolet (UV) irradiation were investigated. Experimental timeseries used inform simulations using multilayer kinetic modeling. Among non-irradiated thin films, coefficient was greatest for at 75% RH (3 × 10–5, corresponding diffusion BrC, DBrC, 3 10–9 cm2 s–1) least same 0% (1 DBrC 1 10–10 s–1). The water-insoluble fell these two (about 1.5 10–5), regardless RH, increased only slightly (8 s–1 9 RH). coefficients both decreased significantly after UV irradiation, consistent transition from viscous liquid solid supported by qualitative microscopy observations. Modeling oxidation primary BrC components atmosphere demonstrated, first, that LLPS may extend lifetime encapsulated species factor moderate high and, also, more than 2.5.

Language: Английский

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Radiative cooling in New York/New Jersey metropolitan areas by wildfire particulate matter emitted from the Canadian wildfires of 2023

Communications Earth & Environment, Journal Year: 2025, Volume and Issue: 6(1)

Published: April 21, 2025

Wildfire particulate matter from Canadian forest fires significantly impacted the air quality in northeastern United States during summer of 2023. Here, we used real-time and time-integrated instrumentation to characterize physicochemical properties radiative effects wildfire reaching metropolitan areas New Jersey/ York this extreme incident. The forcing -352.4 W/m2 derived here based on measured optical explains, some extent, ground level temperature reduction about 3 °C observed City Such negative densely populated megacities may limit natural ventilation, increase residence time background pollutants, exacerbating public health risks. This study highlights importance their potential implications for climate, health.

Language: Английский

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Ultraviolet Irradiation Can Increase the Light Absorption and Viscosity of Primary Brown Carbon from Biomass Burning

ACS Earth and Space Chemistry, Journal Year: 2023, Volume and Issue: 7(10), P. 1882 - 1889

Published: Oct. 9, 2023

The light absorption of brown carbon (BrC) constituents biomass burning organic aerosol (BBOA) changes in the atmosphere, part due to multiphase oxidation. For example, ozonolysis leads whitening primary BrC constituents. Irradiation can also change properties BrC. Here, we investigate interplay between irradiation and processing by measuring reactive uptake ozone thin films BBOA before after exposure UV radiation a photoreactor. Thin were prepared from lower volatility fraction eastern red cedar, species associated with wildfires prescribed fires southern Great Plains, United States. increased mass coefficient at near-UV visible wavelengths. It significantly decreased ozone, which was attributed viscosity material. These absorptivity are consistent results spectrometry tandem differential mobility analysis, show that high-molecular-weight constitute greater total irradiation. Our may have significant implications on warming effect BrC, since here both darkens this material makes it more resistant under conditions investigated.

Language: Английский

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Diffusion Coefficients and Mixing Times of Organic Molecules in β-Caryophyllene Secondary Organic Aerosol (SOA) and Biomass Burning Organic Aerosol (BBOA)

ACS Earth and Space Chemistry, Journal Year: 2021, Volume and Issue: 5(11), P. 3268 - 3278

Published: Nov. 4, 2021

Information on the diffusion rates of organic molecules within secondary aerosol (SOA) and biomass burning (BBOA) is needed to predict impact these aerosols atmospheric chemistry, air quality, climate. Nevertheless, no studies have measured organics SOA generated from β-caryophyllene or BBOA. Here, we in laboratory-generated BBOA as a function water activity (aw) using fluorescence recovery after photobleaching. The was by ozonolysis β-caryophyllene, pyrolysis pine wood. Only water-soluble component studied. coefficients range 1.1 × 10–16 1.3 10–14 m2 s–1 for aw values ranging 0.23 0.86. For BBOA, 7.3 10–17 6.6 0.43. Based values, mixing times 200 nm are less than 1 min >0.23. Since often greater planetary boundary layer temperatures 5 K our experimental temperatures, likely short that part atmosphere types studied here. SOA, compared with predictions based Stokes–Einstein relation fractional relation. both relations, agree predicted coefficients. This work illustrates when radius diffusing average matrix molecules, equation able reasonable accuracy.

Language: Английский

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Hygroscopicity of Secondary Brown Carbon Aerosol from Aqueous Photo-Oxidation of Phenolic Precursors

ACS Earth and Space Chemistry, Journal Year: 2022, Volume and Issue: 6(11), P. 2609 - 2618

Published: Oct. 24, 2022

To understand the impact of light-absorbing organic aerosol, also called brown carbon (BrC), it is necessary to determine extent which direct effect through aerosol–radiation interactions and indirect aerosol–cloud change during its atmospheric residence time. Toward addressing this need, light absorption water uptake secondary BrC aerosol produced from phenolic compounds, abundant biomass burning emissions, were measured. Phenol, catechol, pyrogallol selected form a homologous series, varying in number hydroxyl substituents, they exposed aqueous radical photoreactor, leading formation BrC. The absorptivity was monitored by UV–vis spectroscopy; hygroscopicity determined using hygroscopic tandem differential mobility analyzer. increased within 8 h photo-oxidation then began decreasing. After 24 photo-oxidation, at an atmospherically relevant OH exposure 2.2 × 10–10 mol s L–1, parameters for phenol, similar, i.e., 0.13 ± 0.02, 0.10 respectively, so compounds exhibits similar regardless functionalization precursor. 36 48 continued product mixture exhibited further whitening, parameter catechol did not change. These observations suggest that changes (related effect) precursors are greater than upon aging.

Language: Английский

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