scholarly journals Wintertime Arctic Air Pollution over central Alaska: pre-ALPACA campaign

2021 ◽  
Author(s):  
Eleftherios Ioannidis ◽  
Kathy S. Law ◽  
Jean-Christophe Raut ◽  
Tatsuo Onishi ◽  
Louis Marelle ◽  
...  
Keyword(s):  
Air Pollution ◽  
The United States ◽  
Point Sources ◽  
The Arctic ◽  
Formation Mechanisms ◽  
Winter Conditions ◽  
Local Point ◽  
Temperature Inversions ◽  
Local Emissions ◽  
Pollution Episodes

<p>The wintertime Arctic is influenced by air pollution transported from mid-latitudes, leading to formation of Arctic Haze, as well as local emissions such as combustion for heating and power production in very cold winter conditions. This contributes to severe air pollution episodes, with enhanced aerosol concentrations, inter-dispersed with cleaner periods. However, the formation of secondary aerosol particles (sulphate, organics, nitrate) in cold/dark wintertime Arctic conditions, which could contribute to these pollution episodes, is poorly understood.</p><p>In this study, which contributes to the Air Pollution in the Arctic: Climate, Environment and Societies - Alaskan Layered Pollution and Arctic Chemical Analysis (PACES-ALPACA) initiative, the Weather Research Forecasting Model with chemistry (WRF-Chem) is used to investigate wintertime pollution over central Alaska focusing on the Fairbanks region, during the pre-ALPACA campaign in winter 2019-2020. Fairbanks is the most polluted city in the United States during wintertime, due to high local emissions and the occurrence of strong surface temperature inversions trapping pollutants near the surface.</p><p>Firstly, different WRF meteorological and surface schemes were tested over Alaska with a particular focus on improving simulations of the wintertime boundary layer structure including temperature inversions. An optimal WRF set-up, with increased vertical resolution below 2km, was selected based on evaluation against available data.</p><p>Secondly, a quasi-hemispheric WRF-Chem simulation, using the improved WRF setup, was used to assess large-scale synoptic conditions and to evaluate background aerosols originating from remote anthropogenic and natural sources affecting central Alaska during the campaign. The model was run with Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants (ECLIPSE) v6b anthropogenic emissions and improved sea-spray aerosol emissions. Discrepancies in modelled aerosols compared available data are being investigated (e.g. missing dark formation mechanisms, treatment of removal processes).</p><p>Thirdly, fine resolution simulations, using high resolution emissions (e.g. 2019 CAMS inventory), including local point sources, over the Fairbanks region, were used to investigate chemical and dynamical processes influencing aerosols under different meteorological conditions observed during the field campaign including a cold stable episode and a period with possible mixing of air masses from aloft. The model was evaluated against available aerosol, oxidant (ozone) and aerosol precursor data from surface monitoring sites and collected during the pre-campaign, including vertical profile data collected in the lowest 20m. The sensitivity of modelled aerosols to meteorological factors, such as relative humidity, temperature gradients and vertical mixing under winter conditions are investigated.</p>

Wintertime Arctic Air Pollution over Alaska

2020 ◽  
Author(s):  
Eleftherios Ioannidis ◽  
Kathy Law ◽  
Jean-Christophe Raut ◽  
Tatsuo Onishi ◽  
William R. Simpson ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Pollution ◽  
Black Carbon ◽  
The United States ◽  
Meteorological Conditions ◽  
The Arctic ◽  
Formation Mechanisms ◽  
Local Pollution ◽  
Arctic Haze ◽  
Temperature Inversions

<p><span><span>The Arctic is influenced by long-range transport of aerosols, for example, sulphate, black carbon, and dust from mid-latitude emissions, especially in winter and spring, leading to the formation of Arctic Haze with enhanced aerosol concentrations. However, more recently, local sources of aerosols, such as wood-burning or resource extraction, are highlighted as already being important, but many uncertainties about sources and aerosol processes still remain. For example, the formation of secondary aerosols, such as sulphate, in winter despite very low temperatures and the absence of sunlight. </span></span></p><p><span><span>In this study, which contributes to the international PACES-ALPACA initiative, the Weather Research Forecasting (WRF) and WRF-Chem models are used to investigate wintertime pollution over Alaska with a focus on regions influenced by local pollution, such as Fairbanks and by Arctic Haze, such as </span></span><span><span>Utqiagvik (formerly known as Barrow)</span></span><span><span>. Fairbanks is the most polluted city in the United States during wintertime due to high emissions and the occurrence of strong surface temperature inversion</span></span><span><span>s</span></span><span><span>. </span></span></p><p><span><span>As a first step, background aerosols originating from remote sources were evaluated in large- scale quasi-hemispheric WRF-Chem runs using ECLIPSE anthropogenic emissions. The model performs quite well over Alaska at background sites (e.g. Denali Park) compared to observations from the US Environmental Protection Agency (EPA). Discrepancies in modelled aerosols due to formation mechanisms and aerosol acidity are being investigated. </span></span></p><p><span><span>Secondly, in order to better simulate Arctic aerosols and local pollution episodes, different schemes in WRF were tested over Alaska with a particular focus on improving simulations of the Arctic boundary layer </span></span><span><span>structure and, in particular, wintertime temperature inversions which trap pollution at the ground. In order to simulate these extreme/cold meteorological conditions, different schemes linked to boundary layer physics, surface layer dynamics and the land surface have been tested and evaluated against Integrated Global Radiosonde Archive (IGRA2) and Integrated Surface Database (ISD). The model captures the cold meteorological conditions over Alaska, for example, capturing strong temperature inversions over Utqiagvik and Fairbanks in winter 2012.</span></span></p><p><span><span>Thirdly, WRF-Chem is used to simulate background and local Arctic air pollution</span></span><span><span>, using the improved WRF setup for meteorology over Alaska for winter 2013-2014. The model is being run with Hemispheric Transport of Air Pollution version 2 (HTAP v2) and other high-resolution emission inventories and evaluated against available aerosol data (</span></span><span><span>PM2.5, black carbon, sulphate) over Alaska including data on aerosol chemical </span></span><span><span>properties. The</span></span><span><span> model is used to examine aerosol composition in locally produced and remote aerosols and to identify the origins contributing to aerosol distributions. The sensitivity of modelled aerosols to, for example, meteorological factors, such as humidity, is examined.</span></span></p>

scholarly journals In-situ characterization of layered pollution in the wintertime Arctic atmosphere by small sensors

2021 ◽  
Author(s):  
Tjarda Roberts ◽  
Meeta Cesler-Maloney ◽  
William Simpson ◽  
Jingqui Mao ◽  
Brice Barret ◽  
...  
Keyword(s):  
Air Pollution ◽  
Chemical Analysis ◽  
The Arctic ◽  
Plume Rise ◽  
Aerosol Formation ◽  
Near Surface ◽  
Home Heating ◽  
Vertical Profiling ◽  
Temperature Inversions ◽  
Local Emissions

<p>During the Arctic winter, local emissions (e.g. from home-heating, traffic, power station or industry plumes) coupled to poor dispersion caused by strong temperature inversions can lead to severe air pollution events. For example, each winter, Fairbanks (Alaska) experiences high abundances of gaseous pollutants and particulate matter (PM), leading to air-quality exceedances. However, there is still limited knowledge on the coupled physico-chemical and dynamical processes that cause wintertime Arctic pollution and aerosol formation under the very cold and low light conditions, and where levels of oxidants such as ozone at the surface can become depleted under limited vertical mixing. Here, we demonstrate novel deployment of low cost small sensors measuring PM2.5, gases (CO, NO, NO2, O3) and meteorological parameters (P, T, RH) to characterize Arctic atmospheric composition and properties, including mapping vertical distributions.</p><p>Our three-week pre-ALPACA (Alaskan Layered Pollution and Chemical Analysis) intensive field-campaign took place in downtown Fairbanks in Nov-Dec 2019. Small sensor temperature-dependencies were characterized by instrument cross-comparisons and correction-algorithms developed. Sensors were then deployed near-ground, on the roof of a 19 m building, and on a vertical pulley system set-up along the side of the building for vertical profiling. The small sensors show a strong capability to capture temporal variations in PM2.5, CO, NO and NO<sub>2</sub> and O<sub>3</sub>, across a wide temperature range: surface gas and particle abundances became elevated during a cold-polluted period (temperatures as low as -30 C) and again became elevated during a subsequent warm-polluted period (temperatures around -3 C). Vertical profiling during the warm-polluted period identified strong temperature inversions associated with near-surface layers of high PM2.5 and CO that are distinct from an overlying clean, warm, humid air-mass. During the cold-polluted period, temperature inversions were present but less strong, there was little vertical structure in composition, and PM2.5 was often greater at 20m than at the surface. This finding contrasts with a full winter-season analysis that shows cold surface temperatures typically associated with strong inversions and PM highest at the surface. We invoke plume-rise modelling to show how buoyant plumes from local emissions (e.g. home-heating) can reach heights of about 10-20 m, allowing polluted emissions to rise and accumulate at altitude unless inversions are sufficiently strong to constrain the plume-rise. Causes of the temperature inversions include radiative cooling and advection of overlying warm-air. Our study highlights how small sensor measurements and vertical profiling can help elucidate the coupled processes of atmospheric chemistry, physics, dynamics and emissions that lead to surface air pollution episodes at high latitudes.</p><p>This study forms part of the Alaskan Layered Pollution and Chemical Analysis (ALPACA) project https://alpaca.community.uaf.edu/. We are grateful for technical support from Alaska-DEC, LPC2E, UAF, SEOSS, Alphasense and SouthCoastScience.</p>

scholarly journals Predicted ultrafine particulate matter source contribution across the continental United States during summertime air pollution events

2019 ◽  
Vol 19 (14) ◽  
pp. 9399-9412 ◽  
Author(s):  
Melissa A. Venecek ◽  
Xin Yu ◽  
Michael J. Kleeman
Keyword(s):  
United States ◽  
Air Pollution ◽  
Particulate Matter ◽  
Los Angeles ◽  
San Francisco ◽  
The United States ◽  
Biomass Combustion ◽  
Spatial Gradients ◽  
Ultrafine Particulate Matter ◽  
Pollution Episodes

Abstract. The regional concentrations of airborne ultrafine particulate matter mass (Dp<0.1 µm; PM0.1) were predicted in 39 cities across the United States (US) during summertime air pollution episodes. Calculations were performed using a regional source-oriented chemical transport model with 4 km spatial resolution operating on the National Emissions Inventory created by the U.S. Environmental Protection Agency (EPA). Measured source profiles for particle size and composition between 0.01 and 10 µm were used to translate PM total mass to PM0.1. Predicted PM0.1 concentrations exceeded 2 µg m−3 during summer pollution episodes in major urban regions across the US including Los Angeles, the San Francisco Bay Area, Houston, Miami, and New York. PM0.1 spatial gradients were sharper than PM2.5 spatial gradients due to the dominance of primary aerosol in PM0.1. Artificial source tags were used to track contributions to primary PM0.1 and PM2.5 from 15 source categories. On-road gasoline and diesel vehicles made significant contributions to regional PM0.1 in all 39 cities even though peak contributions within 0.3 km of the roadway were not resolved by the 4 km grid cells. Cooking also made significant contributions to PM0.1 in all cities but biomass combustion was only important in locations impacted by summer wildfires. Aviation was a significant source of PM0.1 in cities that had airports within their urban footprints. Industrial sources, including cement manufacturing, process heating, steel foundries, and paper and pulp processing, impacted their immediate vicinity but did not significantly contribute to PM0.1 concentrations in any of the target 39 cities. Natural gas combustion made significant contributions to PM0.1 concentrations due to the widespread use of this fuel for electricity generation, industrial applications, residential use, and commercial use. The major sources of primary PM0.1 and PM2.5 were notably different in many cities. Future epidemiological studies may be able to differentiate PM0.1 and PM2.5 health effects by contrasting cities with different ratios of PM0.1∕PM2.5. In the current study, cities with higher PM0.1∕PM2.5 ratios (ratio greater than 0.10) include Houston, TX, Los Angeles, CA, Bakersfield, CA, Salt Lake City, UT, and Cleveland, OH. Cities with lower PM0.1 to PM2.5 ratios (ratio lower than 0.05) include Lake Charles, LA, Baton Rouge, LA, St. Louis, MO, Baltimore, MD, and Washington, D.C.

scholarly journals Temporally resolved sectoral and regional contributions to air pollution in Beijing: informing short-term emission controls

2021 ◽  
Vol 21 (6) ◽  
pp. 4471-4485
Author(s):  
Tabish Umar Ansari ◽  
Oliver Wild ◽  
Edmund Ryan ◽  
Ying Chen ◽  
Jie Li ◽  
...  
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Emission Sources ◽  
Short Term ◽  
Emission Reductions ◽  
Daily Average ◽  
Industrial Sectors ◽  
Emission Controls ◽  
Local Emissions ◽  
Pollution Episodes

Abstract. We investigate the contributions of local and regional emission sources to air pollution in Beijing to inform the design of short-term emission control strategies for mitigating major pollution episodes. We use a well-evaluated version of the WRF-Chem model at 3 km horizontal resolution to determine the daily accumulation of pollution over Beijing from local and regional sources in October 2014 under a range of meteorological conditions. Considering feasible emission reductions across residential, transport, power, and industrial sectors, we find that 1 d controls on local emissions have an immediate effect on PM2.5 (particulate matter with diameter less than 2.5 µm) concentrations on the same day but can have lingering effects as much as 5 d later under stagnant conditions. One-day controls in surrounding provinces have the greatest effect in Beijing on the day following the controls but may have negligible effects under northwesterly winds when local emissions dominate. To explore the contribution of different emission sectors and regions, we perform simulations with each source removed in turn. We find that residential and industrial sectors from neighbouring provinces dominate PM2.5 levels in Beijing during major pollution episodes but that local residential emissions and industrial or residential emissions from more distant provinces can also contribute significantly during some episodes. We then perform a structured set of perturbed emission simulations to allow us to build statistical emulators that represent the relationships between emission sources and air pollution in Beijing over the period. We use these computationally fast emulators to determine the sensitivity of PM2.5 concentrations to different emission sources and the interactions between them, including for secondary PM, and to create pollutant response surfaces for daily average PM2.5 concentrations in Beijing. We use these surfaces to identify the short-term emission controls needed to meet the national air quality target of daily average PM2.5 less than 75 µg m−3 for pollution episodes of different intensities. We find that for heavily polluted days with daily mean PM2.5 higher than 225 µg m−3, even emission reductions of 90 % across all sectors over Beijing and surrounding provinces may be insufficient to meet the national air quality standards. These results highlight the regional nature of PM pollution and the challenges of tackling it during major pollution episodes.

scholarly journals Temporally-resolved sectoral and regional contributions to air pollution in Beijing: Informing short-term emission controls

2020 ◽  
Author(s):  
Tabish Umar Ansari ◽  
Oliver Wild ◽  
Edmund Ryan ◽  
Ying Chen ◽  
Jie Li ◽  
...  
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Emission Sources ◽  
Short Term ◽  
Emission Reductions ◽  
Daily Average ◽  
Industrial Sectors ◽  
Emission Controls ◽  
Local Emissions ◽  
Pollution Episodes

Abstract. We investigate the contributions of local and regional emission sources to air quality in Beijing to inform the design of short-term emission control strategies for mitigating major pollution episodes. We use a well-evaluated version of the WRF-Chem model at 3 km horizontal resolution to determine the daily accumulation of pollution over Beijing from local and regional sources in October 2014 under a range of meteorological conditions. Considering feasible emission reductions across residential, transport, power and industrial sectors, we find that one-day controls on local emissions have an immediate effect on PM2.5 concentrations on the same day, but can have lingering effects as much as five days later under stagnant conditions. One-day controls in surrounding provinces have the greatest effect in Beijing on the day following the controls, but may have negligible effects under northwesterly winds when local emissions dominate. To explore the contribution of different emission sectors and regions, we perform simulations with each source removed in turn. We find that residential and industrial sectors from neighbouring provinces dominate PM2.5 levels in Beijing during major pollution episodes, but that local residential emissions and industrial/residential emissions from more distant provinces can also contribute significantly during some episodes. We then perform a structured set of perturbed emission simulations to allow us to build statistical emulators that represent the relationships between emission sources and air pollution in Beijing over the period. We use these computationally fast emulators to determine the sensitivity of PM2.5 concentrations to different emission sources and the interactions between them, including for secondary PM, and to create pollutant response surfaces for daily average PM2.5 concentrations in Beijing. We use these surfaces to identify the short-term emission controls needed to meet the national air quality target of daily average PM2.5 less than 75 μg m−3 for pollution episodes of different intensities. We find that for heavily polluted days with daily mean PM2.5 higher than 225 μg m−3, even emission reductions of 90 % across all sectors over Beijing and surrounding provinces may be insufficient to meet the national air quality standards. These results highlight the regional nature of PM pollution and the challenges of tackling it during major pollution episodes.

scholarly journals Urban Air Pollution May Enhance COVID-19 Case-Fatality and Mortality Rates in the United States

2020 ◽  
Vol 1 (3) ◽  
pp. 100047 ◽  
Author(s):  
Donghai Liang ◽  
Liuhua Shi ◽  
Jingxuan Zhao ◽  
Pengfei Liu ◽  
Jeremy A. Sarnat ◽  
...  
Keyword(s):  
United States ◽  
Air Pollution ◽  
Urban Air Pollution ◽  
Case Fatality ◽  
The United States ◽  
Mortality Rates ◽  
Urban Air

scholarly journals Monetizing the Burden of Childhood Asthma Due to Traffic Related Air Pollution in the Contiguous United States in 2010

2021 ◽  
Vol 18 (15) ◽  
pp. 7864
Author(s):  
Minaal Farrukh ◽  
Haneen Khreis
Keyword(s):  
United States ◽  
Air Pollution ◽  
Economic Impact ◽  
Childhood Asthma ◽  
Ambient Air ◽  
The United States ◽  
The State ◽  
Cost Calculation ◽  
Cost Burden ◽  
Incident Cases

Background: Traffic-related air pollution (TRAP) refers to the wide range of air pollutants emitted by traffic that are dispersed into the ambient air. Emerging evidence shows that TRAP can increase asthma incidence in children. Living with asthma can carry a huge financial burden for individuals and families due to direct and indirect medical expenses, which can include costs of hospitalization, medical visits, medication, missed school days, and loss of wages from missed workdays for caregivers. Objective: The objective of this paper is to estimate the economic impact of childhood asthma incident cases attributable to nitrogen dioxide (NO2), a common traffic-related air pollutant in urban areas, in the United States at the state level. Methods: We calculate the direct and indirect costs of childhood asthma incident cases attributable to NO2 using previously published burden of disease estimates and per person asthma cost estimates. By multiplying the per person indirect and direct costs for each state with the NO2-attributable asthma incident cases in each state, we were able to estimate the total cost of childhood asthma cases attributable to NO2 in the United States. Results: The cost calculation estimates the total direct and indirect annual cost of childhood asthma cases attributable to NO2 in the year 2010 to be $178,900,138.989 (95% CI: $101,019,728.20–$256,980,126.65). The state with the highest cost burden is California with $24,501,859.84 (95% CI: $10,020,182.62–$38,982,261.250), and the state with the lowest cost burden is Montana with $88,880.12 (95% CI: $33,491.06–$144,269.18). Conclusion: This study estimates the annual costs of childhood asthma incident cases attributable to NO2 and demonstrates the importance of conducting economic impacts studies of TRAP. It is important for policy-making institutions to focus on this problem by advocating and supporting more studies on TRAP’s impact on the national economy and health, including these economic impact estimates in the decision-making process, and devising mitigation strategies to reduce TRAP and the population’s exposure.

scholarly journals Ice-Breaking Fleets of the United States and Canada: Assessing the Current State of Affairs and Future Plans

2021 ◽  
Vol 13 (2) ◽  
pp. 703
Author(s):  
Megan Drewniak ◽  
Dimitrios Dalaklis ◽  
Anastasia Christodoulou ◽  
Rebecca Sheehan
Keyword(s):  
United States ◽  
The United States ◽  
Maritime Transportation ◽  
The Arctic ◽  
Polar Ice ◽  
Northwest Passage ◽  
Ice Cap ◽  
Ice Coverage ◽  
Current State ◽  
State Of Affairs

In recent years, a continuous decline of ice-coverage in the Arctic has been recorded, but these high latitudes are still dominated by earth’s polar ice cap. Therefore, safe and sustainable shipping operations in this still frozen region have as a precondition the availability of ice-breaking support. The analysis in hand provides an assessment of the United States’ and Canada’s polar ice-breaking program with the purpose of examining to what extent these countries’ relevant resources are able to meet the facilitated growth of industrial interests in the High North. This assessment will specifically focus on the maritime transportation sector along the Northwest Passage and consists of four main sections. The first provides a very brief description of the main Arctic passages. The second section specifically explores the current situation of the Northwest Passage, including the relevant navigational challenges, lack of infrastructure, available routes that may be used for transit, potential choke points, and current state of vessel activity along these routes. The third one examines the economic viability of the Northwest Passage compared to that of the Panama Canal; the fourth and final section is investigating the current and future capabilities of the United States’ and Canada’s ice-breaking fleet. Unfortunately, both countries were found to be lacking the necessary assets with ice-breaking capabilities and will need to accelerate their efforts in order to effectively respond to the growing needs of the Arctic. The total number of available ice-breaking assets is impacting negatively the level of support by the marine transportation system of both the United States and Canada; these two countries are facing the possibility to be unable to effectively meet the expected future needs because of the lengthy acquisition and production process required for new ice-breaking fleets.

Sign in / Sign up

Export Citation Format

Share Document