Case study evaluation of size-resolved molecular composition and phase state of carbonaceous particles in wildfire influenced smoke from the Pacific Northwest

Vandergrift, Gregory W.; Lata, Nurun Nahar; Mathai, Susan; Ijaz, Amna; Cheng, Zezhen; Shrivastava, Manish; Zhang, Jie; Md Shawon, Abu Sayeed; Kulkarni, Gourihar; Mazzoleni, Lynn R.; Kew, William; China, Swarup

doi:10.1039/d3ea00058c

Cited by 4 publications

(3 citation statements)

References 75 publications

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“…, not commonly detected across all days) are shaded grey. Given the untargeted nature of this study and consequent lack of quantitative information, presence/absence of MFs are used to compare molecular coverage between days as similarly done in previous atmospheric studies with mass spectrometry application. ,,, While this strategy does not reveal what is occurring wholistically during an individual sampling event, it highlights the distinctive characteristics of that event relative to the rest of the sampling period. Here, only 291 MFs (13% by number) were found to be common across all daytime samples, indicating a high variability of MFs across all sampling days.…”

Section: Resultsmentioning

confidence: 99%

“…Nanospray desorption electrospray ionization (nano-DESI) was used to directly interface aerosol sampling with high resolution mass spectrometry (HRMS). The design and implementation of nano-DESI is based upon previous work. ,− While solid-phase extraction was initially explored as part of method development to minimize matrix effects, the minimal particle loadings necessitated the increased sensitivity afforded by direct nano-DESI analyses. Nano-DESI interfaces have also previously been shown to advantageously preserve oligomers and exhibit comparative resistance to matrix effects. ,, Briefly, the nano-DESI apparatus allows for direct, sensitive, in situ sampling of atmospheric particles impacted onto a substrate ( i.e.…”

Section: Methodsmentioning

confidence: 99%

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Chemical Insights into the Molecular Composition of Organic Aerosols in the Urban Region of Houston, Texas

Gautam,

Vandergrift,

Lata

et al. 2024

ACS EST Air

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Molecular functional groups, such as organosulfates (CHOS) and organonitrates (CHNO) are important tracers for field observations of secondary organic aerosols (SOA). While CHOS and CHNO are prevalent in the atmosphere, there is a lack of knowledge regarding daily and day- and night-time variations in these species in the urban atmosphere. Meteorological factors such as wind speed/direction, relative humidity (RH), and temperature can influence the formation of CHOS/CHNO. To investigate these trends, we utilized multimodal chemical imaging and advanced high resolution mass spectrometry techniques to acquire particle speciation and molecular formulas (MFs) associated with day and night sampling periods. Back trajectory analyses revealed the oceanic influence of southern wind airmasses in later June sampling periods with organic fractions <10%. Conversely, northern winds in early June sampling periods contributed to the episodic emergence of extremely low volatile organics (ELVOCs) and organic factions up to 41%. The observed unique MFs to June 3 (223 MFs) and to June 4 (144 MFs) were largely found to be of biogenic rather than anthropogenic origin. Our findings reveal episodic prevalence and temporal distribution of SOA constituents across the urban region of Houston, Texas.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Chemical Insights into the Molecular Composition of Organic Aerosols in the Urban Region of Houston, Texas

Gautam,

Vandergrift,

Lata

et al. 2024

ACS EST Air

Self Cite

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“…Smoke particles are characterized by a complex composition, including solid (e.g., black carbon) and liquid/oil-like organic phases (e.g., SVOCs). Some studies reported an increase in a liquid-like character for smaller particles [75,81]. The dynamics of the liquid and solid particle filtration differ significantly due to the differences in deposition modes (dendritic structures formed by solid particles vs. film formation by liquids), collision kinetics, and differences in the particle/fiber surface interactions.…”

Section: Characterization Of Initial Filtration Efficiency Of Pine Ne...mentioning

confidence: 99%

Evaluation of Filtration Efficiency of Various Filter Media in Addressing Wildfire Smoke in Indoor Environments: Importance of Particle Size and Composition

Shirman,

Liu

2023

Atmosphere

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Sub-micron particles are ubiquitous in the indoor environment, especially during wildfire smoke episodes, and have a higher impact on human health than larger particles. Conventional fibrous air filters installed in heating, ventilation, and air conditioning (HVAC) systems play an important role in controlling indoor air quality by removing various air pollutants, including particulate matter (PM). However, it is evident that the removal efficiency of wildfire smoke PM and its effect on filter performance is significantly under-studied. This study delves into the size-specific removal efficiency of pine needle smoke, a representative of wildfire smoke and emissions. We test an array of filter media with minimum efficiency reporting values (MERV) spanning 11–15. Both size-resolved particle number concentrations and mass concentrations were measured using an Optical Particle Sizer (OPS, TSI, Inc.) and a Scanning Mobility Particle Sizer (SMPS, TSI, Inc.). Furthermore, we characterize the filter media morphology and smoke particles deposited on filter fibers using Scanning Electron Microscopy (SEM) to gain insights into the interaction dynamics of these particles. Our findings add to the comprehension of the relationship between MERV designations and smoke removal efficiency. Such insight can inform standards and guidelines and equip decision-makers with the knowledge needed to initiate measures for mitigating the impact of air pollution, specifically on the indoor environment.

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Impacts of Aging and Relative Humidity on Properties of Biomass Burning Smoke Particles

Schwink,

Mael,

Dunnington

et al. 2024

ACS EST Air

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Quantifying changes in the properties of smoke aerosols under varying conditions is important for understanding the health and environmental impacts of exposure to smoke. Smoke composition, aerosol liquid water content, effective density (ρ eff ), and other properties can change significantly as smoke travels through areas under different ambient conditions and over time. During this study, we measured changes in smoke composition and physical properties due to oxidative aging and exposure to humidity. We found that smoke aging led to SOA formation and increases in ratios of organic carbon to elemental carbon. Aerosol liquid water content increased with increasing relative humidity (RH), and aged smoke took up more water than fresh smoke at all humidity levels, likely due to a combination of changes in aerosol surface polarity at low and medium RH and increases in surface area with aging at high RH. Growth factors ranged from 1.06 ± 0.08 for fresh smoke at low RH to 1.32 ± 0.08 for aged smoke at high RH. Oxidative aging and exposure to humidity led to increases in ρ eff . For 100 nm particles, ρ eff ranged from ∼1.2 for fresh smoke at low RH to ∼1.6 for aged smoke at high RH. Results from these experiments suggest that exposure to humidity leads to smoke restructuring and compaction and/or changes in surface chemistry.

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Case study evaluation of size-resolved molecular composition and phase state of carbonaceous particles in wildfire influenced smoke from the Pacific Northwest

Abstract: Wildfires are significant sources of carbonaceous particles in the atmosphere. Given the dependence of atmospheric processes on particle physical and molecular properties, the interplay between particle size, phase state and...

Cited by 4 publications

References 75 publications

Chemical Insights into the Molecular Composition of Organic Aerosols in the Urban Region of Houston, Texas

Chemical Insights into the Molecular Composition of Organic Aerosols in the Urban Region of Houston, Texas

Evaluation of Filtration Efficiency of Various Filter Media in Addressing Wildfire Smoke in Indoor Environments: Importance of Particle Size and Composition

Impacts of Aging and Relative Humidity on Properties of Biomass Burning Smoke Particles

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