Browsing by Author "Hopke, PK"

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    Anthropogenic perturbations to the atmospheric molybdenum cycle
    (American Geophysical Union, 2021-01-28) Wong, MY; Rathod, SD; Marino, R; Li, LL; Howarth, RW; Alastuey, A; Alaimo, MG; Barraza, F; Carneiro, MC; Chellam, S; Chen, YC; Cohen, DD; Connelly, D; Dongarra, G; Gómez, D; Hand, JL; Harrison, RM; Hopke, PK; Hueglin, c; Kuang, KW; Lambert, F; Liang, J; Losno, R; Maenhaut, W; Milando, C; Monteiro, MIC; Morera-Gómez, Y; Rodríguez, S; Querol, X; Smichowski, P; Varrica, D; Xiao, YH; Xu, YJ; Mahowald, NM
    Molybdenum (Mo) is a key cofactor in enzymes used for nitrogen (N) fixation and nitrate reduction, and the low availability of Mo can constrain N inputs, affecting ecosystem productivity. Natural atmospheric Mo aerosolization and deposition from sources such as desert dust, sea-salt spray, and volcanoes can affect ecosystem function across long timescales, but anthropogenic activities such as combustion, motor vehicles, and agricultural dust have accelerated the natural Mo cycle. Here we combined a synthesis of global atmospheric concentration observations and modeling to identify and estimate anthropogenic sources of atmospheric Mo. To project the impact of atmospheric Mo on terrestrial ecosystems, we synthesized soil Mo data and estimated the global distribution of soil Mo using two approaches to calculate turnover times. We estimated global emissions of atmospheric Mo in aerosols (<10 μm in diameter) to be 23 Gg Mo yr−1, with 40%–75% from anthropogenic sources. We approximated that for the top meter of soil, Mo turnover times range between 1,000 and 1,000,000 years. In some industrialized regions, anthropogenic inputs have enhanced Mo deposition 100-fold, lowering the soil Mo turnover time considerably. Our synthesis of global observational data, modeling, and a mass balance comparison with riverine Mo exports suggest that anthropogenic activity has greatly accelerated the Mo cycle, with potential to influence N-limited ecosystems. © 2022 American Geophysical Union
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    Application of receptor modelling methods
    (Elsevier, 2011-04-01) Hopke, PK; Cohen, DD
    The use of atmospheric compositional data for the identification and apportionment of sources has been ongoing for more than 40 years. Beginning in the 1960s, it was recognized that data analysis techniques could be applied to data and resolve combination of constituents that represent sources. In the late 1970s, these data analysis tools came to be called Receptor Models. This paper traces the early history of receptor models through those early papers and provides a historical introduction to the paper in this special issue showing the state of the art in the field and the application of these modern tools to a variety of atmospheric data. © 2011 Turkish National Committee for Air Pollution Research and Control (TUNCAP). © 2020 Elsevier B.V.
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    Long range transport of soil dust and smoke pollution in the South Asian Region
    (Turkish National Committee for Air Pollution Research and Control (TUNCAP), 2011-04-01) Begum, BA; Biswas, SK; Pandit, GG; Saradhi, IV; Waheed, S; Siddique, N; Seneviratn, MCS; Cohen, DD; Markwitz, A; Hopke, PK
    Transboundary transport of air pollution in the South Asian region has been an issue of increasing importance over the past several decades. Long–range transport of anthropogenic pollution is contrasted with that of pollution produced by natural processes such as dust storms or natural forest fires. Airborne particulate matter datasets covering the period from 2002 to 2007 from the neighboring countries like Bangladesh, India, Pakistan and Sri Lanka were used to find the source areas that are primarily responsible for long range transported pollutants. All four countries collected samples with the same type of sampler and follow the same technique for mass and BC measurements. It was found that high fine soil contributions were from dust storms. On the other hand, smoke in this region mainly comes from northern India where agricultural waste is often burned. © Author(s)2011
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    Urban air quality in the Asian region
    (Elsevier, 2008-10-01) Hopke, PK; Cohen, DD; Begum, BA; Biswas, SK; Ni, BF; Pandit, GG; Santoso, M; Chung, YS; Davy, P; Markwitz, A; Waheed, S; Siddique, N; Santos, FL; Pabroa, PCB; Seneviratne, MCS; Wimolwattanapun, W; Bunprapob, S; Vuong, TB; Hien, PD; Markowicz, A
    Over the past decade, member states of the Regional Co-operation Agreement (RCA), an intergovernmental agreement for the East Asia and Pacific region under the auspices of the IAEA with the assistance of international organizations and financial institutions such as the World Bank and the Asian Development Bank, have started to set in place policies and legislation for air pollution abatement. To support planning and evaluate the effectiveness of control programs, data are needed that characterizes urban air quality. The focus of this measurement program describe in this report is on size segregated particulate air pollution. Such airborne particulate matter can have a significant impact on human health and urban visibility. These data provide the input to receptor models that may permit the mitigation of these impacts by identification and quantitative apportionment of the particle sources. The aim of this report is to provide an overview of the measurements of concentrations and composition of particulate air pollution in two size fractions across the participating countries. For many of the large cities in this region, the measured particulate matter concentrations are greater than air quality standards or guidelines that have been adopted in developed countries. © 2008, Elsevier Ltd.