COVID-19 perturbation on US air quality and human health impact assessment

PNAS Nexus, Journal Year: 2023, Volume and Issue: 3(1)

Published: Dec. 21, 2023

Abstract The COVID-19 stay-at-home orders issued in the United States caused significant reductions traffic and economic activities. To understand pandemic's perturbations on US emissions impacts urban air quality, we developed near-real-time bottom-up emission inventories based publicly available energy datasets, simulated changes a chemical transport model, evaluated quality against various observations. pandemic affected across broad-based sectors persisted to 2021. Compared with 2019 business-as-usual scenario, resulted annual decreases of 10–15% ozone (O3) fine particle (PM2.5) gas-phase precursors, which are about two four times larger than long-term trends during 2010–2019. While COVID-induced transportation industrial activities, particularly April–June 2020, overall national pollutants, meteorological variability nation led local increases or mixed between 2020. Over full year (April 2020 March 2021), 3–4% population-weighted fourth maximum daily 8-h average O3 PM2.5. Assuming these could be maintained future, result would 4–5% decrease premature mortality attributable ambient pollution, suggesting that continued efforts mitigate gaseous pollutants from anthropogenic sources can further protect human health pollution future.

Language: Английский

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Reactive Nitrogen Partitioning Enhances the Contribution of Canadian Wildfire Plumes to US Ozone Air Quality

Geophysical Research Letters, Journal Year: 2024, Volume and Issue: 51(15)

Published: Aug. 6, 2024

Abstract Quantifying the variable impacts of wildfire smoke on ozone air quality is challenging. Here we use airborne measurements from 2018 Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption, and Nitrogen (WE‐CAN) to parameterize emissions reactive nitrogen (NO y ) wildfires into peroxyacetyl nitrate (PAN; 37%), NO 3 − (27%), (36%) in a global chemistry‐climate model with 13 km spatial resolution over contiguous US. The partitioning, compared emitting all as NO, reduces bias near‐fire plumes sampled by aircraft enhances downwind 5–10 ppbv when Canadian travel Washington, Utah, Colorado, Texas. Using multi‐platform observations, identify smoke‐influenced days daily maximum 8‐hr average (MDA8) 70–88 Kennewick, Salt Lake City, Denver Dallas. On these days, enhanced MDA8 5–25 ppbv, through produced remotely during plume transport locally via interactions urban emissions.

Language: Английский

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Measurement report: Emission factors of NH₃ and NH_x for wildfires and agricultural fires in the United States

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(4), P. 2331 - 2343

Published: Feb. 17, 2023

Abstract. During the 2019 Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) study, NASA DC-8 carried out in situ chemical measurements smoke plumes emitted from wildfires agricultural fires contiguous United States. The payload included a modified proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) for fast measurement of gaseous ammonia (NH3) high-resolution aerosol (AMS) submicron particulate ammonium (NH4+). We herein report data collected 6 Western States, 2 prescribed grassland Central 1 forest fire Southern 66 small Southeastern Smoke contained double triple digit ppb levels NH3. In wildfire plumes, significant fraction NH3 had already been converted NH4+ at time sampling (≥2 h after emission). Substantial amounts were also detected freshly corn rice field fires. present comprehensive set emission factors NHx, with NHx=NH3+NH4+. Average NHx States 1.86±0.75 g kg−1 2.47±0.80 fuel burned, respectively. 0.89±0.58 1.74±0.92 kg−1, Our show no clear inverse correlation between combustion efficiency (MCE) emissions. observed emissions significantly higher than measured previous laboratory experiments FIREX FireLab 2016 study.

Language: Английский

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Forecasting Daily Fire Radiative Energy Using Data Driven Methods and Machine Learning Techniques

Journal of Geophysical Research Atmospheres, Journal Year: 2024, Volume and Issue: 129(16)

Published: Aug. 24, 2024

Abstract Increasing impacts of wildfires on Western US air quality highlights the need for forecasts smoke emissions based dynamic modeled wildfires. This work utilizes knowledge weather, fuels, topography, and firefighting, combined with machine learning other statistical methods, to generate 1‐ 2‐day fire radiative energy (FRE). The models are trained data covering 2019 2021 evaluated 2020. For 1‐day (2‐day) forecasts, random forest model shows most skill, explaining 48% (25%) variance in observed daily FRE when all available predictors compared 2% (<0%) explained by persistence extreme year also improved skill forecasting day‐to‐day increases decreases FRE, 28% (39%) increase (decrease) days predicted, identified 62% (60%) accuracy. Error tends toward under severe weather. Sensitivity analysis that near‐surface weather latest contribute model. When was subsets training produced agencies (e.g., Canadian or Forest Services), comparable if not better performance achieved (1‐day R 2 = 0.39–0.48, 0.13–0.34). is used compute emissions, so these results demonstrate potential models.

Language: Английский

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Emission Factors for Crop Residue and Prescribed Fires in the Eastern US During FIREX‐AQ

Journal of Geophysical Research Atmospheres, Journal Year: 2023, Volume and Issue: 128(18)

Published: Sept. 2, 2023

Abstract Agricultural and prescribed burning activities emit large amounts of trace gases aerosols on regional to global scales. We present a compilation emission factors (EFs) ratios from the eastern portion Fire Influence Regional Global Environments Air Quality (FIREX‐AQ) campaign in 2019 United States, which sampled crop residues other fire fuels. FIREX‐AQ provided comprehensive chemical characterization 53 residue 22 fires. Crop burned at different modified combustion efficiencies (MCE), with corn higher MCE than fuel types. Prescribed fires lower (<0.90) is typical, while grasslands (0.90) normally observed due moist, green, growing season Most non‐methane volatile organic compounds (NMVOCs) were significantly anticorrelated except for ethanol NMVOCs that measured less certainty. identified 23 species where differed by more 50% same MCE. EFs greater related agricultural use composition as well oxygenated possibly presence metals such potassium. monoterpenes (5×). average generally agreed previous study US but had disagreements compilations. observations show importance regionally‐specific fuel‐specific first steps reduce uncertainty modeling air quality impacts emissions.

Language: Английский

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Ensemble flow reconstruction in the atmospheric boundary layer from spatially limited measurements through latent diffusion models

Physics of Fluids, Journal Year: 2023, Volume and Issue: 35(12)

Published: Dec. 1, 2023

Due to costs and practical constraints, field campaigns in the atmospheric boundary layer typically only measure a fraction of volume interest. Machine learning techniques have previously successfully reconstructed unobserved regions flow canonical fluid mechanics problems two-dimensional geophysical flows, but these not yet been demonstrated three-dimensional layer. Here, we conduct numerical analogue campaign with spatially limited measurements using large-eddy simulation. We pose reconstruction as an inpainting problem, reconstruct realistic samples turbulent, use latent diffusion model. The model generates physically plausible turbulent structures on larger spatial scales, even when input observations cover less than 1% volume. Through combination qualitative visualization quantitative assessment, demonstrate that meaningfully diverse conditioned just one observation. These serve initial conditions for simulation code. find models show promise potential other applications problems.

Language: Английский

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Probing Atmospheric Aerosols by Multimodal Mass Spectrometry Techniques: Revealing Aging Characteristics of Its Individual Molecular Components

ACS Earth and Space Chemistry, Journal Year: 2023, Volume and Issue: 7(12), P. 2498 - 2510

Published: Dec. 11, 2023

Detailed chemical characterization of biomass burning organic aerosol (OA) was performed using a synergistic combination multimodal mass spectrometry techniques. OA analyzed in situ high-resolution time-of-flight spectrometer (HR-ToF-AMS) and an extractive electrospray ionization (EESI-MS) deployed onboard the NASA DC-8 research aircraft. Additionally, complementary filter samples were collected for offline laboratory analysis high-performance liquid chromatography interfaced with photodiode array (HPLC-PDA-HRMS). During flight on August 3, 2019, which focused Williams Flats Fire, WA, HR-ToF-AMS data revealed abundant presence sulfur (OS) species as prominent components OA. These OS identified based their unique fragmentation. Further investigation HPLC-PDA-HRMS MSn fragmentation allowed us to identify molecular characteristics these unusual species. The dominant compounds detected during found be alkylbenzene sulfonates. Organosulfate, nitroaromatic, oxygenated aromatic also identified. Guided by HRMS results, time-resolved aging profiles selected individual retrieved from real-time EESI-MS sets evaluate evolution emission plume. Notably, sulfonate showed remarkable stability over 8 h atmospheric transport. In contrast, common organosulfates displayed short apparent half-life times that low 1.2 h, indicating susceptibility aging. nitroaromatic exhibited relatively slower aging, average 1.8 2.2 respectively.

Language: Английский

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Biomass burning CO emissions: exploring insights through TROPOMI-derived emissions and emission coefficients

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(17), P. 10159 - 10186

Published: Sept. 13, 2024

Abstract. Emissions from biomass burning are a significant source of air pollution, which can adversely impact quality and ecosystems thousands kilometres downwind. These emissions be estimated by bottom-up approach that relies on fuel consumed standardized emission factors. also commonly derived with top-down approach, using satellite-observed fire radiative power (FRP) as proxy for consumption. Biomass directly satellite trace gas observations, including carbon monoxide (CO). Here, we explore the potential satellite-derived CO rates provide new insights into understanding globally, respect to differences in regions vegetation type. Specifically, use TROPOMI (Tropospheric Monitoring Instrument) high-spatial-resolution datasets derive individual fires between 2019 2021 globally. Using synthetic data (with known emissions), show direct estimate methodology has 34 % uncertainty deriving (and total 44 wind column uncertainty). From TROPOMI-derived emissions, biome-specific coefficients (emissions relative FRP) combining estimates FRP Moderate Resolution Imaging Spectrometer (MODIS). used establish annual inventories burning, showing Southern Hemisphere Africa highest (over 25 global 300–390 Mt(CO) yr−1 2003–2021), almost broadleaved evergreen tree fires. A comprehensive comparison estimates, approaches, provides insight strengths weaknesses each method: FINN2.5 higher factor 2 5, than all other assessed this study. Trends over past decades examined different around globe, have, whole, decreased (by 5.1 8.7 yr−1), where some experience increased others emissions.

Language: Английский

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Early Season 2023 Wildfires Generated Record‐Breaking Surface Ozone Anomalies Across the U.S. Upper Midwest

Geophysical Research Letters, Journal Year: 2024, Volume and Issue: 51(22)

Published: Nov. 26, 2024

Abstract During summer 2023 Canada experienced its most intense wildfire season on record. Smoke plumes from these fires advected across the United States (U.S.) Upper Midwest, producing regional scale surface enhancements of PM 2.5 and ozone, as recorded by U.S. monitoring network. These events are notable because they occurred early in fire (May 15‐June 30), produced highest regional‐scale ozone levels ever northern tier during (May–June) or late (July‐August) summer. Specifically, Midwest 50th percentile was greater than any other year since 1995, when network had sufficient coverage to assess levels; 90th 2002. Satellite aircraft measurements demonstrate availability precursors production within smoke plumes.

Language: Английский

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Exploring the processes controlling secondary inorganic aerosol: evaluating the global GEOS-Chem simulation using a suite of aircraft campaigns

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(2), P. 771 - 795

Published: Jan. 21, 2025

Abstract. Secondary inorganic aerosols (sulfate, nitrate, and ammonium, SNA) are major contributors to fine particulate matter. Predicting concentrations of these species is complicated by the cascade processes that control their abundance, including emissions, chemistry, thermodynamic partitioning, removal. In this study, we use 11 flight campaigns evaluate GEOS-Chem model performance for SNA. Across all campaigns, best sulfate (R2 = 0.51; normalized mean bias (NMB) 0.11) worst nitrate (R2=0.22; NMB 1.76), indicating substantive deficiencies in simulation. Thermodynamic partitioning reproduces total well (R2=0.79; 0.09), but actual (i.e., ε(NO3-)= NO3- / TNO3) challenging assess given limited sets full gas- particle-phase observations needed ISORROPIA II. particular, ammonia not often included aircraft more routine measurements would help constrain sources SNA bias. Model sensitive changes emissions dry wet deposition, with modest improvements associated inclusion different chemical loss production pathways acid uptake on dust, N2O5 uptake, photolysis). However, sensitivity tests show only reduction bias, no improvement skill R2), implying work improve description as a whole.

Language: Английский

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