scholarly journals Regional pollution potentials of megacities and other major population centers

2007 ◽  
Vol 7 (14) ◽  
pp. 3969-3987 ◽  
Author(s):  
M. G. Lawrence ◽  
T. M. Butler ◽  
J. Steinkamp ◽  
B. R. Gurjar ◽  
J. Lelieveld
Keyword(s):  
Long Range ◽  
Atmospheric Chemistry ◽  
Atmospheric Transport ◽  
Deep Convection ◽  
Vertical Mixing ◽  
Geographical Location ◽  
Point Sources ◽  
High Latitudes ◽  
Near Surface ◽  
Regional Pollution

Abstract. Megacities and other major population centers represent large, concentrated sources of anthropogenic pollutants to the atmosphere, with consequences for both local air quality and for regional and global atmospheric chemistry. The tradeoffs between the regional buildup of pollutants near their sources versus long-range export depend on meteorological characteristics which vary as a function of geographical location and season. Both horizontal and vertical transport contribute to pollutant export, and the overall degree of export is strongly governed by the lifetimes of pollutants. We provide a first quantification of these tradeoffs and the main factors influencing them in terms of "regional pollution potentials", metrics based on simulations of representative tracers using the 3-D global model MATCH (Model of Atmospheric Transport and Chemistry). The tracers have three different lifetimes (1, 10, and 100 days) and are emitted from 36 continental large point sources. Several key features of the export characteristics emerge. For instance, long-range near-surface pollutant export is generally strongest in the middle and high latitudes, especially for source locations in Eurasia, for which 17–34% of a tracer with a 10-day lifetime is exported beyond 1000 km and still remains below 1 km altitude. On the other hand, pollutant export to the upper troposphere is greatest in the tropics, due to transport by deep convection, and for six source locations, more than 50% of the total mass of the 10-day lifetime tracer is found above 5 km altitude. Furthermore, not only are there order of magnitude interregional differences, such as between low and high latitudes, but also often substantial intraregional differences, which we discuss in light of the regional meteorological characteristics. We also contrast the roles of horizontal dilution and vertical mixing in reducing the pollution buildup in the regions including and surrounding the sources. For some regions such as Eurasia, dilution due to long-range horizontal transport governs the local and regional pollution buildup; however, on a global basis, differences in vertical mixing are dominant in determining the pollution buildup both around and further downwind of the source locations.

scholarly journals Regional pollution potentials of megacities and other major population centers

2006 ◽  
Vol 6 (6) ◽  
pp. 13323-13366 ◽  
Author(s):  
M. G. Lawrence ◽  
T. M. Butler ◽  
J. Steinkamp ◽  
B. R. Gurjar ◽  
J. Lelieveld
Keyword(s):  
Long Range ◽  
Atmospheric Chemistry ◽  
Atmospheric Transport ◽  
Deep Convection ◽  
Geographical Location ◽  
Point Sources ◽  
Western India ◽  
High Latitudes ◽  
Near Surface ◽  
Regional Pollution

Abstract. Megacities and other major population centers represent important, concentrated sources of anthropogenic pollutants to the atmosphere, with consequences for both local air quality and for regional and global atmospheric chemistry. The tradeoff between the regional buildup of pollutants near their sources versus long-range export depends on meteorological characteristics which vary as a function of geographical location and season. Both horizontal and vertical transport contribute to pollutant export, and the overall degree of export is strongly governed by the chemical lifetimes of pollutants. We provide a first quantification of this tradeoff and the main factors influencing it in terms of "regional pollution potentials", metrics based on simulations of artificial, representative tracers using the 3-D global model MATCH (Model of Atmospheric Transport and Chemistry). The tracers have three different lifetimes (1, 10, and 100 days) and are emitted from 36 continental point sources representing the 30 current largest cities around the world plus 6 additional major population centers. Several key features of the export characteristics emerge: 1) long-range near-surface pollutant export is generally strongest in the middle and high latitudes, especially for source locations in Eurasia; 2) on the other hand, pollutant export to the upper troposphere is greatest in the tropics, due to transport by deep convection; 3) not only are there order of magnitude interregional differences, such as between low and high latitudes, but also often substantial intraregional differences, for instance between the sources in western India and Pakistan versus eastern India and Bangladesh; 4) contrary to what one might initially expect, efficient long-range export does not necessarily correspond with a more significant dilution of pollutants near their source, rather the amount of low-level, long-range export (e.g., below 1 km and beyond 1000 km) is well-correlated with exceedences of surface density thresholds on regional scales near the source (e.g., within ~1000 km), implying that pollutant buildup to high densities in the surface layer of the region surrounding the source location is more strongly influenced by vertical than horizontal transport.

scholarly journals Accounting for the vertical distribution of emissions in atmospheric CO<sub>2</sub> simulations

2019 ◽  
Vol 19 (7) ◽  
pp. 4541-4559 ◽  
Author(s):  
Dominik Brunner ◽  
Gerrit Kuhlmann ◽  
Julia Marshall ◽  
Valentin Clément ◽  
Oliver Fuhrer ◽  
...  
Keyword(s):  
Power Plants ◽  
Atmospheric Transport ◽  
Traditional Approach ◽  
Vertical Mixing ◽  
Point Sources ◽  
Small Scale ◽  
Near Surface ◽  
Industrial Facilities ◽  
Scale Modeling ◽  
The Impact

Abstract. Inverse modeling of anthropogenic and biospheric CO2 fluxes from ground-based and satellite observations critically depends on the accuracy of atmospheric transport simulations. Previous studies emphasized the impact of errors in simulated winds and vertical mixing in the planetary boundary layer, whereas the potential importance of releasing emissions not only at the surface but distributing them in the vertical was largely neglected. Accounting for elevated emissions may be critical, since more than 50 % of CO2 in Europe is emitted by large point sources such as power plants and industrial facilities. In this study, we conduct high-resolution atmospheric simulations of CO2 with the mesoscale Consortium for Small-scale Modeling model extended with a module for the simulation of greenhouse gases (COSMO-GHG) over a domain covering the city of Berlin and several coal-fired power plants in eastern Germany, Poland and Czech Republic. By including separate tracers for anthropogenic CO2 emitted only at the surface or according to realistic, source-dependent profiles, we find that releasing CO2 only at the surface overestimates near-surface CO2 concentrations in the afternoon on average by 14 % in summer and 43 % in winter over the selected model domain. Differences in column-averaged dry air mole XCO2 fractions are smaller, between 5 % in winter and 8 % in summer, suggesting smaller yet non-negligible sensitivities for inversion modeling studies assimilating satellite rather than surface observations. The results suggest that the traditional approach of emitting CO2 only at the surface is problematic and that a proper allocation of emissions in the vertical deserves as much attention as an accurate simulation of atmospheric transport.

scholarly journals Accounting for the vertical distribution of emissions in atmospheric CO<sub>2</sub> simulations

2018 ◽  
Author(s):  
Dominik Brunner ◽  
Gerrit Kuhlmann ◽  
Julia Marshall ◽  
Valentin Clément ◽  
Oliver Fuhrer ◽  
...  
Keyword(s):  
Power Plants ◽  
Mesoscale Model ◽  
Atmospheric Transport ◽  
Traditional Approach ◽  
Vertical Mixing ◽  
Point Sources ◽  
Near Surface ◽  
Industrial Facilities ◽  
The Impact ◽  
The Vertical Distribution

Abstract. Inverse modeling of anthropogenic and biospheric CO2 fluxes from ground-based and satellite observations critically depends on the accuracy of atmospheric transport simulations. Previous studies emphasized the impact of errors in simulated winds and vertical mixing in the planetary boundary layer, whereas the potential importance of releasing emissions not only at the surface but distributing them in the vertical was largely neglected. Accounting for elevated emissions may be critical, since more than 50 % of CO2 in Europe is emitted by large point sources such as power plants and industrial facilities. In this study we conduct high-resolution atmospheric simulations of CO2 with the mesoscale model COSMO-GHG over a domain covering the city of Berlin and several coal-fired power plants in eastern Germany, Poland and the Czech Republic. By including separate tracers for anthropogenic CO2 emitted only at the surface or according to realistic, source-dependent profiles, we find that releasing CO2 only at the surface overestimates near-surface CO2 concentrations in the afternoon on average by 14 % in summer and 43 % in winter over the selected model domain. Differences in column mean dry air mole fractions XCO2 are smaller, between 5 % in winter and 8 % in summer, suggesting smaller yet non-negligible sensitivities for inversion modeling studies assimilating satellite rather than surface observations. The results suggests that the traditional approach of emitting CO2 only at the surface is problematic and that a proper allocation of emissions in the vertical deserves as much attention as an accurate simulation of atmospheric transport.

Inorganic contaminants in Arctic Alaskan ecosystems: long-range atmospheric transport or local point sources?

1995 ◽  
Vol 160-161 ◽  
pp. 323-335 ◽  
Author(s):  
J. Ford ◽  
D. Landers ◽  
D. Kugler ◽  
B. Lasorsa ◽  
S. Allen-Gil ◽  
...  
Keyword(s):  
Long Range ◽  
Atmospheric Transport ◽  
Point Sources ◽  
Inorganic Contaminants ◽  
Local Point

scholarly journals Evaluation of size segregation of elemental carbon emission in Europe: influence on atmospheric long-range transportation

2015 ◽  
Vol 15 (21) ◽  
pp. 31053-31087 ◽  
Author(s):  
Y. Chen ◽  
Y. F. Cheng ◽  
S. Nordmann ◽  
W. Birmili ◽  
H. A. C. Denier van der Gon ◽  
...  
Keyword(s):  
Long Range ◽  
Elemental Carbon ◽  
Atmospheric Transport ◽  
Transport Processes ◽  
Point Sources ◽  
Size Segregation ◽  
Wind Pattern ◽  
Coarse Mode ◽  
Nearby Point ◽  
Emission Fraction

Abstract. Elemental Carbon (EC) has significant impact on human health and climate change. In order to evaluate the size segregation of EC emission and investigation of its influence on atmospheric transport processes in Europe, we used the fully coupled online Weather Research and Forecasting/Chemistry model (WRF-Chem) at a resolution of 2 km focusing on a region in Germany, in conjunction with a high-resolution EC emission inventory. The ground meteorology conditions, vertical structure and wind pattern were well reproduced by the model. The simulations of particle number/mass size distributions were evaluated by observations taken at the central European background site Melpitz. The fine mode aerosol was reasonably well simulated, but the coarse mode was substantially overestimated by the model. We found that it was mainly due to the nearby point source plume emitting a high amount of EC in the coarse mode. The comparisons between simulated EC and Multi-angle Absorption Photometers (MAAP) measurements at Melpitz, Leipzig-TROPOS and Bösel indicated that coarse mode EC (ECc) emission in the nearby point sources might be overestimated by a factor of 2–10. The emission fraction of EC in coarse mode was overestimated by about 10–30 % for Russian and 5–10 % for Eastern Europe (e.g.: Poland and Belarus), respectively. This overestimation in ECc emission fraction makes EC particles having less opportunity to accumulate in the atmosphere and participate to the long range transport, due to the shorter lifetime of coarse mode aerosol. The deposition concept model showed that the transported EC mass from Warsaw and Moskva to Melpitz may be reduced by 25–35 and 25–55 % respectively, due to the overestimation of ECc emission fraction. This may partly explain the underestimation of EC concentrations for Germany under eastern wind pattern in some other modelling research.

Impact of model resolution and transport uncertainties on the representation of CO2 emission plumes by global and regional atmospheric transport models

2020 ◽  
Author(s):  
Dominik Brunner ◽  
Jean-Matthieu Haussaire ◽  
Julia Marshall ◽  
Arjo Segers ◽  
Hugo Denier van der Gon ◽  
...  
Keyword(s):  
High Resolution ◽  
Power Plants ◽  
Atmospheric Transport ◽  
Vertical Mixing ◽  
Temporal Variations ◽  
Paris Agreement ◽  
Transport Models ◽  
Transport Modelling ◽  
Near Surface ◽  
Total Column

&lt;p&gt;Emissions of carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) will have to be drastically reduced in the coming decades to reach the goal of the Paris Agreement to limit the global temperature increase to no more than 2&amp;#176;C. To support this process, Europe is planning to establish a CO&lt;sub&gt;2&lt;/sub&gt; anthropogenic emission monitoring system, which will assist countries, cities and facility operators in monitoring their emissions and evaluating the progress towards their reduction targets. The system will combine measurements from ground-based networks with observations from a new constellation of CO&lt;sub&gt;2&lt;/sub&gt; satellites, which will provide high-resolution images of total column CO&lt;sub&gt;2&lt;/sub&gt; allowing tracking the plumes of large emission sources. A suite of atmospheric transport modelling systems will assimilate these observations and inversely estimate emissions from the continental to the country scale and down to the scale of individual cities and power plants.&lt;/p&gt;&lt;p&gt;In the European project &quot;CO&lt;sub&gt;2&lt;/sub&gt; Human Emissions&quot; (CHE), the components of such a modelling framework are explored, which includes the generation of a library of realistic atmospheric CO&lt;sub&gt;2&lt;/sub&gt; simulations. These &quot;nature runs&quot; are obtained by running global and regional atmospheric transport models at the highest possible resolution affordable today and using state-of-the-art inputs of anthropogenic emissions and natural CO&lt;sub&gt;2&lt;/sub&gt; fluxes. The library includes global simulations at 9 km x 9 km resolution with the CAMS-IFS model, European simulations at 5 km x 5 km resolution with WRF-GHG, COSMO-GHG and LOTOS-EUROS, and high-resolution simulations at 1 km x 1 km over the city of Berlin and several power plants with COSMO-GHG and LOTOS-EUROS.&lt;/p&gt;&lt;p&gt;Here we analyse and compare the model simulations to address the following questions: How realistically are atmospheric gradients in CO&lt;sub&gt;2&lt;/sub&gt; caused by spatial and temporal variations in biospheric and anthropogenic fluxes and by atmospheric dynamics represented at the different model resolutions? What resolution is required to resolve the plumes of individual cities and power plants? How large are the differences in near surface and total column CO&lt;sub&gt;2&lt;/sub&gt; due to uncertainties in atmospheric transport including uncertainties in vertical mixing? Information on transport uncertainties is derived from an ensemble of CAMS-IFS simulations and from the spread between the individual models.&lt;/p&gt;&lt;p&gt;Answering these questions is critical for the design of a future operational capacity to monitor anthropogenic CO&lt;sub&gt;2&lt;/sub&gt; emissions, which should optimally support decision makers at facility, city, and country scale as well as the global stocktake process of the Paris Agreement.&lt;/p&gt;

Long-range atmospheric transport of mercury to ecosystems, and the importance of anthropogenic emissions—a critical review and evaluation of the published evidence

1997 ◽  
Vol 5 (2) ◽  
pp. 99-120 ◽  
Author(s):  
T A Jackson
Keyword(s):  
Long Range ◽  
Fossil Fuels ◽  
Atmospheric Transport ◽  
Sediment Cores ◽  
Terrestrial Ecosystems ◽  
Point Sources ◽  
Weight Of Evidence ◽  
Anthropogenic Emissions ◽  
Remote Lakes ◽  
Published Evidence

Literature on the long-range atmospheric transport of both anthropogenic and naturally occurring mercury (Hg) to terrestrial and aquatic ecosystems was reviewed for the purpose of assessing the quantitative importance and environmental significance of the anthropogenic emissions. The weight of evidence, comprising many different kinds of data that corroborate each other independently, supports the following conclusions. (i) Approximately 5000 t of anthropogenic Hg are introduced into the atmosphere every year, both by direct emission from sources of pollution and by reemission of previously deposited Hg from diffuse secondary sources in the environment. The primary emissions ( 4000 t) result from various human activities, especially the combustion of fossil fuels (notably coal) and solid wastes. Natural emissions amount to about 2000 t/year. (ii) Although some of the annual anthropogenic Hg output (about half the quantity emitted by primary sources) is deposited near its point sources, the rest (a total of 3000 t) is subject to transport over great distances by atmospheric circulation, resulting in measurable contamination of terrestrial and aquatic environments and organisms up to several thousand kilometers from the points of origin. Indeed, a number of remote ecosystems receive most of their Hg input from the atmosphere. (iii) The available evidence supports the generally accepted conclusion that the Hg enrichment commonly seen in the uppermost horizons of sediment cores from remote lakes is due primarily to contamination by airborne anthropogenic Hg in the recent past, rather than postdepositional redistribution of Hg. Although postdepositional alteration may result in detectable remobilization of sedimentary Hg, its effects on total Hg profiles in lake sediment cores have been found, thus far, to be negligible. (iv) Atmospheric transport of anthropogenic Hg to aquatic and terrestrial ecosystems is a cause for concern, as the Hg is accumulating, to a greater or lesser extent, in organisms (e.g., fish in remote lakes). Moreover, the Hg is associated with, and interacts with, other by-products of fossil fuel combustion, including the strong acids responsible for acid precipitation. The acids aggravate the effects of Hg pollution by furthering the accumulation of methyl Hg in fish inhabiting ill-buffered lakes. Contamination of the atmosphere with Hg and associated pollutants is a serious international problem that calls for reduction or elimination of emissions.

scholarly journals COSMOGENIC 14CO FOR ASSESSING THE OH-BASED SELF-CLEANING CAPACITY OF THE TROPOSPERE

Radiocarbon ◽  
2021 ◽  
pp. 1-19
Author(s):  
Carl A M Brenninkmeijer ◽  
Sergey S Gromov ◽  
Patrick Jöckel
Keyword(s):  
Point Source ◽  
Hydroxyl Radicals ◽  
Atmospheric Chemistry ◽  
Sampling Method ◽  
Atmospheric Transport ◽  
Vertical Mixing ◽  
High Energy ◽  
Transport Processes ◽  
Future Work ◽  
Unique Application

ABSTRACT An application of radiocarbon (14C) in atmospheric chemistry is reviewed. 14C produced by cosmic neutrons immediately forms 14CO, which reacts with hydroxyl radicals (OH) to 14CO2. By this the distribution and seasonality (the lifetime of 14CO is ∼1 month) of the pivotal atmospheric oxidant OH can be established. 14CO measurement is a complex but unique application which benefitted enormously from the realization of AMS, bearing in mind that 14CO abundance is of the order of merely 10 molecules per cm3 not only provides 14CO an independent measure for the OH based self-cleansing capacity of the troposphere, but also enabled detection of 14C production due to high energy solar protons in 1989. Although its production takes place throughout the atmosphere and does not have the character of a point source, transport processes in the atmosphere affect the distribution of 14CO. Vertical mixing in the troposphere renders gradients in its production rate less critical, but considerable meridional gradients exist. One question has remained open, namely confirmation of calculated 14C production by direct measurement. A new sampling method is proposed. The conclusions are a guide to future work on 14CO in relation to OH and atmospheric transport.

scholarly journals Multi-scale modeling study of the source contributions to near-surface ozone and sulfur oxides levels over California during the ARCTAS-CARB period

2011 ◽  
Vol 11 (7) ◽  
pp. 3173-3194 ◽  
Author(s):  
M. Huang ◽  
G. R. Carmichael ◽  
S. N. Spak ◽  
B. Adhikary ◽  
S. Kulkarni ◽  
...  
Keyword(s):  
Long Range ◽  
Atmospheric Chemistry ◽  
Surface Ozone ◽  
Long Range Transport ◽  
Sulfur Oxides ◽  
Near Surface ◽  
Fire Emissions ◽  
Multi Scale ◽  
Range Transport ◽  
Local Emissions

Abstract. Chronic high surface ozone (O3) levels and the increasing sulfur oxides (SOx = SO2+SO4) ambient concentrations over South Coast (SC) and other areas of California (CA) are affected by both local emissions and long-range transport. In this paper, multi-scale tracer, full-chemistry and adjoint simulations using the STEM atmospheric chemistry model are conducted to assess the contribution of local emission sourcesto SC O3 and to evaluate the impacts of transported sulfur and local emissions on the SC sulfur budgetduring the ARCTAS-CARB experiment period in 2008. Sensitivity simulations quantify contributions of biogenic and fire emissions to SC O3 levels. California biogenic and fire emissions contribute 3–4 ppb to near-surface O3 over SC, with larger contributions to other regions in CA. During a long-range transport event from Asia starting from 22 June, high SOx levels (up to ~0.7 ppb of SO2 and ~1.3 ppb of SO4) is observed above ~6 km, but they did not affect CA surface air quality. The elevated SOx observed at 1–4 km is estimated to enhance surface SOx over SC by ~0.25 ppb (upper limit) on ~24 June. The near-surface SOx levels over SC during the flight week are attributed mostly to local emissions. Two anthropogenic SOx emission inventories (EIs) from the California Air Resources Board (CARB) and the US Environmental Protection Agency (EPA) are compared and applied in 60 km and 12 km chemical transport simulations, and the results are compared withobservations. The CARB EI shows improvements over the National Emission Inventory (NEI) by EPA, but generally underestimates surface SC SOx by about a factor of two. Adjoint sensitivity analysis indicated that SO2 levels at 00:00 UTC (17:00 local time) at six SC surface sites were influenced by previous day maritime emissions over the ocean, the terrestrial emissions over nearby urban areas, and by transported SO2 from the north through both terrestrial and maritime areas. Overall maritime emissions contribute 10–70% of SO2 and 20–60% fine SO4 on-shore and over the most terrestrial areas, with contributions decreasing with in-land distance from the coast. Maritime emissions also modify the photochemical environment, shifting O3 production over coastal SC to more VOC-limited conditions. These suggest an important role for shipping emission controls in reducing fine particle and O3 concentrations in SC.

scholarly journals On interpreting studies of tracer transport by deep cumulus convection and its effects on atmospheric chemistry

2008 ◽  
Vol 8 (20) ◽  
pp. 6037-6050 ◽  
Author(s):  
M. G. Lawrence ◽  
M. Salzmann
Keyword(s):  
Atmospheric Chemistry ◽  
Large Scale ◽  
Deep Convection ◽  
Convective Transport ◽  
Advective Transport ◽  
Tracer Transport ◽  
Transport Models ◽  
Mass Fluxes ◽  
Split Treatment ◽  
The Mean

Abstract. Global chemistry-transport models (CTMs) and chemistry-GCMs (CGCMs) generally simulate vertical tracer transport by deep convection separately from the advective transport by the mean winds, even though a component of the mean transport, for instance in the Hadley and Walker cells, occurs in deep convective updrafts. This split treatment of vertical transport has various implications for CTM simulations. In particular, it has led to a misinterpretation of several sensitivity simulations in previous studies in which the parameterized convective transport of one or more tracers is neglected. We describe this issue in terms of simulated fluxes and fractions of these fluxes representing various physical and non-physical processes. We then show that there is a significant overlap between the convective and large-scale mean advective vertical air mass fluxes in the CTM MATCH, and discuss the implications which this has for interpreting previous and future sensitivity simulations, as well as briefly noting other related implications such as numerical diffusion.

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