Investigating processes influencing simulation of local Arctic wintertime anthropogenic pollution in Fairbanks, Alaska, during ALPACA-2022

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(2), P. 1063 - 1104

Published: Jan. 28, 2025

Abstract. Lagrangian tracer simulations are deployed to investigate processes influencing vertical and horizontal dispersion of anthropogenic pollution in Fairbanks, Alaska, during the Alaskan Layered Pollution Chemical Analysis (ALPACA) 2022 field campaign. Simulated concentrations carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxides (NOx), including surface elevated sources, highest at under very cold stable conditions. enhancements above (50–300 m) mainly attributed power plant emissions. Both sources contribute Fairbanks' regional that is transported downwind, primarily south-west, may wintertime Arctic haze. Inclusion a novel plume rise treatment considers presence temperature inversion layers leads improved agreement with observed CO NOx plumes, discrepancies to, for example, displacement plumes by modelled winds. At surface, model results show variability largely driven meteorology and, lesser extent, emissions, although simulated tracers sensitive dispersion. Modelled underestimation polluted conditions considerably following inclusion substantial increases diesel vehicle emissions temperatures (e.g. factor 6 −30 °C). In contrast, overestimation SO2 deficiencies (5–18 space heating This study highlights need improvements local simulation boundary layers.

Language: Английский

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Surface distributions and vertical profiles of trace gases (CO, O₃, NO, NO₂) in the Arctic wintertime boundary layer using low-cost sensors during ALPACA-2022

Atmospheric measurement techniques, Journal Year: 2025, Volume and Issue: 18(5), P. 1163 - 1184

Published: March 7, 2025

Abstract. Electrochemical gas sensors (EGSs) have been used to measure the surface distributions and vertical profiles of trace gases in wintertime Arctic boundary layer during Alaskan Layered Pollution Chemical Analysis (ALPACA) field experiment Fairbanks, Alaska, January–February 2022. The MICRO for MEasurements GASes (MICROMEGAS) instrument set up with CO, NO, NO2, O3 EGSs was operated on ground at an outdoor reference site downtown Fairbanks calibration, while board a vehicle moving through city its surroundings tethered balloon, helikite, edge city. To calibrate measurements, machine learning (ML) calibration methods were tested. For each method, prediction performed coincident MICROMEGAS analyser measurements site. parameters provided by manufacturer led best agreement between EGS analyser, no ML method needed calibration. Pearson correlation coefficient R is 0.82, slope linear regression data 1.12. mean bias not significant, but root square error (290 ppbv, parts per billion volume) rather large because CO concentrations reaching several ppmv (parts million Fairbanks. O3, agreements datasets obtained artificial neural network, multi-layer perceptron. these three gases, coefficients are higher than 0.95, slopes regressions range 0.93–1.04. biases, which 1 ± 3, 0 4, 3 12 ppbv respectively, significant. Measurements from car round 21 January presented highlight ability quantify variability target surrounding hills. flew 11 times maximum 350 m above level (a.g.l.) helikite statistics over dataset show that median characterized almost constant mixing ratios. values 140, 8, 32 O3. Extreme detected low-O3 high-NO2 NO 100 150 a.g.l. minimum levels (5th percentile) 5 NO2 (95th 40 occur around 200 peaks aloft linked pollution plumes originating power plants such as those documented flight 20 February.

Language: Английский

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Predicted impacts of heterogeneous chemical pathways on particulate sulfur over Fairbanks (Alaska), the Northern Hemisphere, and the Contiguous United States

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(5), P. 3287 - 3312

Published: March 18, 2025

Abstract. A portion of Alaska's Fairbanks North Star Borough was designated as nonattainment for the 2006 24 h fine particulate matter 2.5 µm or less in diameter (PM2.5) National Ambient Air Quality Standards (NAAQS) 2009. PM2.5 NAAQS exceedances mainly occur during dark and cold winters, when temperature inversions form trap high emissions at surface. Sulfate (SO42-), often second-largest contributor to mass these wintertime PM episodes, is underpredicted by atmospheric chemical transport models (CTMs). Most CTMs account primary SO42- secondary formed via gas-phase oxidation sulfur dioxide (SO2) in-cloud aqueous dissolved S(IV). Dissolution reaction SO2 aerosols are generally not included but can be represented heterogeneous reactive uptake may help better represent concentrations observed winters. In addition, hydroxymethanesulfonate (HMS), a species sometimes misidentified SO42-, known Heterogeneous formation HMS aerosol liquid water (ALW) implemented Community Multiscale (CMAQ) modeling system. CMAQ simulations were performed episodes (2008) well over Northern Hemisphere Contiguous United States (CONUS) 2015–2016. The added chemistry reduced model mean sulfate bias ∼ 0.6 µg m−3 winter episode Fairbanks, AK. Improvements performance also seen Beijing haze events (reducing 2.9 S m−3). This additional improves modeled summertime southeastern US, with implications future biogenic organosulfates.

Language: Английский

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The Chemical Assessment of Surfaces and Air (CASA) Study: Using chemical and physical perturbations in a test house to investigate indoor processes

Environmental Science Processes & Impacts, Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 1, 2024

The Chemical Assessment of Surfaces and Air (CASA) study aimed to understand how chemicals transform in the indoor environment using perturbations (

Language: Английский

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Indoor–Outdoor Oxidative Potential of PM_2.5 in Wintertime Fairbanks, Alaska: Impact of Air Infiltration and Indoor Activities

ACS ES&T Air, Journal Year: 2024, Volume and Issue: 1(3), P. 188 - 199

Published: Feb. 14, 2024

The indoor air quality of a residential home during winter in Fairbanks, Alaska, was investigated and contrasted with outdoor levels. Twenty-four-hour average filter samples were collected from January 17 to February 25, 2022, area high PM2.5 concentrations. oxidative potential determined using the dithiothreitol-depletion assay (OPDTT). For unoccupied house, background indoor-to-outdoor (I/O) ratio mass-normalized OP (OPmDTT), measure intrinsic health-relevant properties aerosol, less than 1 (0.53 ± 0.37), implying loss aerosol toxicity as transported indoors. This may result transport volatility losses driven by large gradients temperature (average −19°C/average 21 °C) or relative humidity RH 78%/average 11%), both. Various activities, including pellet stove use, simple cooking experiments, incense burning, mixtures these conducted. experiments produced highly variable OPmDTT. emissions had lowest values, while highest. Correlations between volume-normalized OPDTT (OPvDTT), relevant exposure, mass concentration much lower compared those environments. suggests that alone can be poor indicator possible adverse effects various emissions. These findings highlight importance considering both quantity particles sources (chemical composition), health metrics for quality.

Language: Английский

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Can commercial Doppler lidars serve air quality applications? Results from a field comparison with PM ₁₀ , PM _2.5 , and granulometric observations in a multi-influenced harbor city

Aerosol Science and Technology, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 15

Published: Nov. 25, 2024

More than a thousand Doppler lidars are already deployed in the world for wind energy or airport safety applications. Although such instruments optimized measurements, if they could also be qualified aerosol observations, would provide cheap and immediately accessible large database, which open perspectives pollutant dispersion studies. A scanning lidar was 8 months Dunkerque, 200,000 inhabitants harbor city northern France. The performed horizontal scans to acquire collocated observations with ground-level in-situ concentrations of PM10 PM2.5 (β-absorption monitor) particle size distributions (optical counter, OPC). signal from commercial cannot inverted into optical properties, so intensity directly compared concentrations. There no overall correlation between mass (r2 = 0.041 0.182 PM2.5), but better results were obtained number concentration 0.7 µm diameter channel OPC 0.519) cumulated volume over all channels below 2 cutoff 0.433). coefficient exceeded 0.8 during several periods lasting up 5–6 days, even varying meteorological conditions. However, coupling network sensors appears more promising, as it not possible determine global conversion factor turn concentration.

Language: Английский

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Multi-year, high-time resolution aerosol chemical composition and mass measurements from Fairbanks, Alaska

Environmental Science Atmospheres, Journal Year: 2024, Volume and Issue: 4(6), P. 685 - 698

Published: Jan. 1, 2024

Fairbanks-North Star Borough, Alaska (FNSB) regularly experiences some of the worst wintertime air quality in United States.

Language: Английский

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Residential Wood Burning and Vehicle Emissions as Major Sources of Environmentally Persistent Free Radicals in Fairbanks, Alaska

Environmental Science & Technology, Journal Year: 2024, Volume and Issue: 58(32), P. 14293 - 14305

Published: Aug. 2, 2024

Environmentally persistent free radicals (EPFRs) play an important role in aerosol effects on air quality and public health, but their atmospheric abundance sources are poorly understood. We measured EPFRs contained PM2.5 collected Fairbanks, Alaska, winter 2022. find that EPFR concentrations were enhanced during surface-based inversion correlate strongly with incomplete combustion markers, including carbon monoxide elemental (R2 > 0.75). exhibit moderately good correlations PAHs, biomass burning organic aerosols, potassium 0.4). also observe strong of hydrocarbon-like Fe Ti 0.6), single-particle mass spectrometry measurements reveal internal mixing iron. These results suggest residential wood vehicle tailpipes major nontailpipe emissions, such as brake wear road dust, may contribute to the stabilization EPFRs. Exposure observed (18 ± 12 pmol m–3) would be equivalent smoking ∼0.4–1 cigarette daily. Very 0.8) hydroxyl radical formation surrogate lung fluid indicate exposure induce oxidative stress human respiratory tract.

Language: Английский

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In situ vertical observations of the layered structure of air pollution in a continental high-latitude urban boundary layer during winter

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(6), P. 3687 - 3715

Published: March 27, 2025

Abstract. Vertical in situ measurements of aerosols and trace gases were conducted Fairbanks, Alaska, during winter 2022 as part the Alaskan Layered Pollution Chemical Analysis campaign (ALPACA). Using a tethered balloon, study explores dispersion pollutants continental high-latitude stable boundary layer (SBL). 24 flights revealed stratified SBL structure with different pollution layers lowest tens meters atmosphere, offering unprecedented detail. Surface emissions generally accumulated surface mixing (ML) extending to an average 51 m, well-mixed sublayer (MsL) reaching 22 m. The height concentrations within ML strongly influenced by local wind driven nearby topography under anticyclonic conditions. During strong radiative cooling, drainage flow increased turbulence near surface, altering temperature profile deepening ML. Above ML, decreased but showed clear signs freshly released anthropogenic emissions. Higher above elevated inversions, levels similar previously reported Arctic haze concentrations, even though Fairbanks' outflow below inversions up 6 times higher, likely due power plant In indicated that gas particle tracer ratios plumes differed significantly from those surface. Overall, correlated stratification emission heights, emphasizing need for improved representation sources air quality models enhance forecasts.

Language: Английский

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Concluding remarks: Atmospheric chemistry in cold environments

Faraday Discussions, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

This paper summarizes the meeting on Atmospheric Chemistry in Cold Environments held London. It puts into context of this rapidly evolving scientific field and provides perspectives based discussions. Photo credit: K. Jacot.

Language: Английский

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