Grantee Research Project Results
2010 Progress Report: Effects of Future Emissions and a Changed Climate on Urban Air Quality
EPA Grant Number: R833371Title: Effects of Future Emissions and a Changed Climate on Urban Air Quality
Investigators: Jacobson, Mark Z. , Streets, David G.
Institution: Stanford University , Argonne National Laboratory
EPA Project Officer: Chung, Serena
Project Period: February 1, 2007 through January 31, 2011 (Extended to January 31, 2012)
Project Period Covered by this Report: February 1, 2010 through January 31,2011
Project Amount: $899,984
RFA: Consequences of Global Change For Air Quality (2006) RFA Text | Recipients Lists
Research Category: Climate Change , Air
Objective:
This is a project to study the effects of changes in emissions on climate and the resulting feedback of climate change to air quality. We are examining the effects of emission changes resulting from standard IPCC-SRES future emission scenarios and from different fuel types. We also are developing new numerical algorithms as part of this project.Progress Summary:
This report summarizes the cumulative progress during this project, through the fourth year (Jan. 31, 2011). To date, 12 papers relevant to the project goals have been published. These include (1) a study on the effect of future A1B and B1 emission scenarios on the emissions of natural gases and particles, global climate, and global air quality (Jacobson and Streets, 2009); (2) a study examining the effects of ambient and emitted carbon dioxide on air quality and human health in the U.S. (Jacobson, 2008a); (3) a study examining the effects of local CO2 domes on air pollution health (Jacobson, 2010a); (4) a study examining the effect on global climate and stratospheric ozone of converting the world’s fossil-fuel onroad vehicles (FFOV) to hydrogen fuel cell vehicles (HFCV), where the hydrogen is produced by wind-powered electrolysis (Jacobson, 2008b); (5) a study examining the short-term effects of irrigation and albedo differences due to agriculture on California and Los Angeles air pollution and climate (Jacobson, 2008c); (6) a study describing the development of a fluid-land boundary treatment scheme for inviscid shallow water flows that conserves the domain-summed mass, energy, vorticity, and potential enstrophy in multiply-connected domains, i.e., in domains encompassing arbitrarily shaped islands (Ketefian and Jacobson, 2009); (7) a study describing an expansion of the fluid land boundary treatment from stair step to continuous boundary conditions (Ketefian and Jacobson, 2011); (8) a study examining the temperature dependence of ethanol versus gasoline emissions on air quality using a 13,600-reaction chemical mechanism (Ginnebaugh, et al., 2010); (9) a study evaluating a 13,600-reaction chemical mechanism in a 3-D nested model (Jacobson and Ginnebaugh, 2010); (10) a study examining the effects on global and Arctic climate and air pollution health of fossil-fuel soot versus biofuel soot and gases, and methane (Jacobson, 2010b); (11) a study discussing a new numerical method for solving drop breakup following collision/coalescence in rain-forming clouds (Jacobson, 2011); and (12) a data analysis study examining the variation of cloud optical depth with aerosol optical depth (Ten Hoeve, et al., 2011). These papers are described below.
Jacobson and Streets (2009) examined the effect of future emission changes on natural emissions, global climate, and air quality. Speciated sector- and region-specific 2030 emission factors were developed to produce gas and particle emission inventories that followed Special Report on Emission Scenarios (SRES) A1B and B1 emission trajectories. Current and future climate model simulations were run in which anthropogenic emission changes affected climate, which fed back to natural emissions from lightning (NO, NO2, HONO, HNO3, N2O, H2O2, HO2, CO), soils (dust, bacteria, NO, N2O, H2, CH4, H2S, DMS, OCS, CS2), the ocean (bacteria, sea spray, DMS, N2O, H2, CH4), and vegetation (pollen, spores, isoprene, monoterpenes, methanol, other VOCs) and photosynthesis/respiration. New methods were derived to calculate lightning flash rates as a function of size-resolved collisions and other physical principles and pollen, spore, and bacteria emissions. Although the B1 scenario was “cleaner” than the A1B scenario, global warming increased more in the B1 scenario because much A1B warming was masked by additional reflective aerosol particles. Thus, neither scenario is entirely beneficial from a climate and health perspective, and the best control measure is to reduce warming gases and warming/cooling particles together. Lightning emissions declined by ~3% in the B1 scenario and by ~12% in the A1B scenario as the number of ice crystals, thus charge-separating bounceoffs, decreased. Net primary production increased by ~2% in both scenarios. Emissions of isoprene and monoterpenes increased by ~1% in the A1B scenario and 4-5% in the B1 scenario. Nearsurface ozone increased by ~14% in the A1B scenario and by ~4% in the B1 scenario, reducing ambient isoprene in the latter case. Gases from soils increased in both scenarios due to higher temperatures. Near-surface PM2.5 mass increased by ~2% in the A1B scenario and decreased by ~2% in the B1 scenario. The resulting 1.4% higher aerosol optical depths in the A1B scenario decreased ocean wind speeds and thus ocean sea spray and bacteria emissions; ~5% lower AODs in the B1 scenario had the opposite effect.
Another paper that was published quantifies the link between carbon dioxide alone and air pollution health problems (Jacobson, 2008a). Previous studies of the effects of global warming on air pollution did not isolate carbon dioxide’s effect alone or quantify the global-scale carbon dioxide-induced temperature and water vapor change effects on both regional-scale particle and gas aerosol pollution and the resulting health effects. The conclusion of this study was that each degree Celsius rise in temperature in the U.S. may lead to an additional 1000 airpollution-related deaths per year (with a range of uncertainty provided in the paper). About 300 of these additional deaths per year occur in California, which has about 12% of the U.S. population, indicating a disproportionate share of deaths in California. The study involved the global-through-urban simulation of climate and its feedback to air pollution.
Jacobson (2010a) performed a followup study examining the effects of local emissions of CO2 on the formation of CO2 domes over cities and the resulting effects of such domes on local air quality and health. The study found, through data-evaluated numerical modeling with telescoping domains from the globe to the U.S., California, and Los Angeles, that local CO2 emissions in isolation may increase local ozone and particulate matter. Although health impacts of such changes are uncertain, they are of concern, and it was estimated that that local CO2 emissions may increase premature mortality by 50-100 and 300-1000/yr in California and the U.S., respectively. As such, reducing locally-emitted CO2 may reduce local air pollution mortality even if CO2 in adjacent regions is not controlled. If correct, this result contradicts the basis for air pollution regulations worldwide, none of which considers controlling local CO2 based on its local health impacts. It also suggests that a “cap and trade” policy should consider the location of CO2 emissions, as the underlying assumption of the policy is incorrect.
Jacobson (2008b) examined the effect on global climate and stratospheric ozone of converting the world’s fossil-fuel onroad vehicles (FFOV) to hydrogen fuel cell vehicles (HFCV), where the hydrogen is produced by wind-powered electrolysis. The study found that such a conversion should reduce gas and aerosol emissions. Such reductions should reduce stratospheric and tropospheric aerosol and cloud acidification and surface area and increase precipitation/wet removal, all of which feed back to increasing stratospheric ozone. Over the long term, a conversion may cool the troposphere and warm the stratosphere, speeding ozonelayer recovery further. Wind-HFCV should simultaneously reduce tropospheric ozone and replace similar amounts of H2 (at a 3% leakage rate) and H2O emitted by FFOV. Thus, wind-HFCV (and similarly renewable-powered battery electric vehicles) should also reduce stratospheric ozone and decrease tropospheric pollution. Because this study examined the effect of a different vehicle technology on global climate and air pollution, it was directly relevant to this project.
Another paper published as part of this project examined the short-term effects of irrigation and albedo differences due to agriculture on California and Los Angeles air pollution and climate (Jacobson, 2008c). High-resolution irrigation, land use, soil, albedo, and emission data were applied at the subgrid scale in the nested global-through-urban GATOR-GCMOM model to examine these issues following a comparison of baseline model results with data. It was found that, in August, irrigation alone increased soil moisture, increasing nighttime but decreasing daytime ground temperatures more, causing a net ground cooling in California and Los Angeles. Agriculture was calculated to increase the albedo of the northern Central Valley but decrease that of the southern valley more relative to nonagricultural land today, offsetting part of the cooling due to irrigation alone. The spatial maximum day-night average August cooling in the Central Valley due to irrigation plus albedo differences from agriculture was 0.9 K at 30 m height and 2.3 K at the ground, in range of an historic 0.74-2.4 K cooling at 2 m attributed to heavily-irrigated agriculture in an independent data study. When averaged over all model cells containing >0% irrigation, irrigation alone and irrigation plus albedo differences decreased day-night average 2-m temperatures by 0.44 K and 0.16 K, respectively, indicating greater local than regional effects of agriculture. In the Central Valley, irrigation increased the relative humidity, cloud water, and precipitation, shifting aerosol and soluble gas mass to clouds and rain. In the valley and Los Angeles, agriculture stabilized air, decreasing wind speeds and turbulence, increasing pollution in the absence of rain. Thus, when enhancing clouds and precipitation, agriculture decreased pollution; otherwise, agriculture increased pollution. Agriculture in parts of the polluted eastern Los Angeles basin increased fine particulate matter by ~2% and ozone by ~0.1%. All results were robust to a change in the simulation date, although further evaluation is needed to better quantify effects of agriculture on climate and air quality.
Ketefian and Jacobson (2009) developed a fluid-land boundary treatment scheme for inviscid shallow water flows that conserves the domain-summed mass, energy, vorticity, and potential enstrophy in multiply-connected domains, i.e., in domains encompassing arbitrarilyshaped islands. The boundary scheme was derived from a previous scheme that conserves all four domain-summed quantities only in singly-connected periodic domains, i.e., periodic domains without islands. It consists of a method for including land in the model along with evolution equations for the vorticity and extrapolation formulas for the depth at fluid-land boundaries. Proofs of mass, energy, vorticity, and potential enstrophy conservation are given. Numerical simulations are carried out demonstrating the conservation properties of the boundary scheme for inviscid flows and comparing its performance with that of four alternative boundary schemes. The first of these uses extrapolation and finite-differencing to calculate the vorticity at boundaries; the second enforces the free-slip boundary condition; the third enforces the superslip condition; and the fourth enforces the no-slip condition. The comparison shows that the new scheme is the only one of the five that conserves all four domain-summed quantities, and it is the only one that simultaneously prevents a spurious energy cascade to the smallest resolved scales and maintains the correct flow orientation with respect to an external forcing.
Ketefian and Jacobson (2011) developed a numerical scheme for treating fluid–land boundaries in inviscid shallow water flows. The method approximates boundary profiles with piecewise linear segments (shaved cells) while conserving the domain-summed mass, energy, vorticity, and potential enstrophy. The new scheme is a generalization of a previous scheme that also conserves these quantities but used stairsteps to approximate boundary profiles. Numerical simulations were carried out demonstrating the conservation properties and accuracy of the piecewise linear boundary scheme (the PLS) for inviscid flow and comparing its performance with the stairstep scheme (the STS). It was found that while both schemes conserved all four domain-summed quantities, the PLS generated depth and velocity fields that were one-half to one order more accurate than those generated by the STS, and it generated vorticity and potential vorticity fields that were at least as accurate as those generated by the STS and often more accurate. The higher accuracy of the PLS is due to its ability to generate smoother flow fields near boundaries of arbitrary shape.
Another important aspect of this project was the implementation, evaluation, and application of a largely-explicit chemical mechanism. Two papers were published on this topic (Ginnebaugh, et al., 2010 and Jacobson and Ginnebaugh, 2010). These papers are discussed briefly, in turn.
Ginnebaugh et al. (2010) combined the Master Chemical Mechanism (MCM, version 3.1, LEEDS University) with the SMVGEAR II chemical ordinary differential solver to provide the speed necessary to simulate complex chemistry in 0-D or 3-D. The MCM has over 13,500 organic reactions and 4600 species. SMVGEAR II is a sparse-matrix Gear solver that reduces the computation time significantly while maintaining any specified accuracy. The chemical mechanism was tested for its accuracy in comparison with smog chamber data. A box model version was then combined with species-resolved tailpipe emissions data for E85 (15% gasoline, 85% ethanol fuel blend) and gasoline vehicles to compare the impact of each on nitrogen oxides, organic gases, and ozone as a function of ambient temperature and background concentrations, using Los Angeles in 2020 as a base case. Two different emissions data sets were used: one was a compilation of exhaust and evaporative data taken near 24 C and the other from exhaust data taken at 7 C. Diurnal effects were examined over two-day scenarios. It was found that, accounting for chemistry and dilution alone, the average ozone concentrations through the range of temperatures tested were higher with E85 than with gasoline by 7 part per billion volume (ppbv) at higher temperatures (summer conditions) to 39 ppbv at low temperatures and low sunlight (winter conditions) for an area with a high nitrogen oxide (NOx) to non-methane organic gas (NMOG) ratio. The results suggest that E85's effect on health through ozone formation becomes increasingly more significant relative to gasoline at colder temperatures due to the change in exhaust emission composition at lower temperatures. Acetaldehyde and formaldehyde concentrations were also much higher with E85 at cold temperatures, which is a concern because both are considered to be carcinogens. These results could have implications for wintertime use of E85. Peroxyacetyl nitrate (PAN), another air pollutant of concern, increased with E85 as well. The sensitivity of the results to box size, initial background concentrations, background emissions, and water vapor were also examined.
Until this project, gas photochemistry had not been simulated beyond a few hundred reactions in a 3-D atmospheric model. In Jacobson and Ginnebaugh (2010), 4675 gases and 13,626 tropospheric and stratospheric reactions were implemented into the 3-D GATORGCMOM climate-pollution model, and model results were compared with data and with results from a condensed 152-gas/297-reaction mechanism when the model was nested at increasing resolution from the globe to California to Los Angeles. Gases included C1-C12 organic degradation products and H-, O-, N-, Cl-, Br-, Fl-, and S-containing inorganics. Organic reactions were from the Master Chemical Mechanism. Photolysis coefficients for 2644 photoprocesses and heating rates for 1909 photolyzing gases were solved with an online radiative code in each grid cell using quantum yield/cross section data over 86 UV/visible wavelengths. Spatial/temporal emissions of >110 gases were derived from the 2005 U.S. National Emission Inventory. The condensed mechanism was a modified Carbon-Bond IV (MCBIV). Three-day simulation results indicate that the more-explicit mechanism reduced the O3 gross error against data versus the MCBIV error against data by only ~2 percentage points (from 28.3% to 26.5%) and NO2 and HCHO by ~6 percentage points in Los Angeles. While more-explicit photochemistry improved results, the condensed mechanism was not the main source of ozone error. The more explicit mechanism, which treated absorptive heating by more photolyzing gases, also resulted in a slightly different magnitude of feedbacks to meteorological variables and back to gases themselves, than did the less-explicit mechanism. The computer time for all processes in GATOR-GCMOM with the more-explicit mechanism (solved with SMVGEAR II in all domains) was only ~3.7 times that with the MCBIV despite the factors of 31 and 46 increases in numbers of species and reactions, respectively.
Next, a study was carried out to examine the short-term (~15 year) effects of controlling fossil-fuel soot (FS) [black carbon (BC), primary organic matter (POM), and S(IV) (H2SO4(aq), HSO4-, and SO42-)], solid-biofuel soot and gases (BSG) (BC, POM, S(IV), K+, Na+, Ca2+, Mg2+, NH4+, NO3-, Cl- and several dozen gases, including CO2 and CH4), and methane on global and Arctic temperatures, cloudiness, precipitation, and atmospheric composition (Jacobson, 2010b). Climate response simulations were run with GATOR-GCMOM, accounting for both microphysical (indirect) and radiative effects of aerosols on clouds and precipitation. The model treated discrete size-resolved aging and internal-mixing of aerosol soot, discrete size-resolved evolution of clouds/precipitation from externally- and internally-mixed aerosol particles, and soot absorption in aerosols, clouds/precipitation, and snow/sea ice. Eliminating FS, FS+BSG (FSBSG), and CH4 in isolation were found to reduce global surface air temperatures by a statistically significant 0.3-0.5 K, 0.4-0.7 K, and 0.2-0.4 K, respectively, averaged over 15 y. As net global warming (0.7-0.8 K) is due mostly to gross pollutant warming from fossil-fuel greenhouse gases (2-2.4 K), and FSBSG (0.4-0.7 K) offset by cooling due to non-FSBSG aerosol particles (-1.7 to -2.3 K), removing FS and FSBSG may reduce 13-16% and 17-23%, respectively, of gross warming to date. Reducing FS, FSBSG, CH4 in isolation may reduce warming above the Arctic Circle by up to ~1.2 K, ~1.7 K, and ~0.9 K, respectively. Both FS and BSG contribute to warming, but FS is a stronger contributor per unit mass emission. However, BSG may cause eight times more mortality than FS. The global e-folding lifetime of emitted BC (from all fossil sources) against internal mixing by coagulation was ~3 hours, similar to data, and that of all BC against dry plus wet removal was ~4.5 days. About 90% of emitted FS BC mass was lost to internal mixing by coagulation; ~7% to wet removal, ~3% to dry removal, and a residual remaining airborne. Of all emitted- plus internally-mixed BC, ~92% was wet removed and ~8% dry removed, with a residual remaining airborne. The 20- and 100 year surface temperature response per unit continuous emissions (STRE) (similar to global warming potentials – GWPs) of BC in FS were 4500-7200 and 2900-4600, respectively; those of BC in BSG were 2100-4000 and 1060-2020, respectively; and those of CH4 were 52-92 and 29-63, respectively. Thus, FSBSG may be the second-leading cause of warming after CO2. Controlling FS and BSG may be a faster method of reducing Arctic ice loss and global warming than other options, including controlling CH4 or CO2, although all controls are needed.
Jacobson (2011) developed a new volume- and volume-concentration-conserving, positive-definite, unconditionally-stable iterative numerical scheme for solving temporary cloud/raindrop coalescence followed by breakup and coupled it with an existing non-iterative, volume- and volume-concentration-conserving collision/coalescence (coagulation) scheme. The breakup scheme alone compares nearly exactly with a constant-kernel analytical solution at a 300-s time step. The combined coagulation/breakup schemes are stable and conservative, regardless of the time step and number of size bins, and convergent with higher temporal and size resolution. The schemes were designed with these characteristics in mind for use in long-term global or regional simulations. The use of 30 geometrically-spaced size bins and a time step of 60 s provides a good compromise between obtaining sufficient accuracy (relative to a much higher resolution result) and speed although solutions at 600 s time step and 30 bins are stable and conservative and take 1/8th the computer time. The combined coagulation/breakup schemes were implemented into the nested GATOR-GCMOM global-urban climate/weather/air pollution model. Coagulation was solved over liquid, ice, and graupel distributions and breakup simultaneously over the liquid distribution. Each distribution included 30 size bins and 16 chemical components per bin. Timing tests demonstrate the feasibility of the scheme in longterm global simulations.
Finally, Ten Hoeve, et al. (2011) use satellite data to examine the impact of aerosols on clouds during the Amazonian biomass burning season in Brazil. They found that cloud optical depth (COD) increases with increasing aerosol optical depth (AOD) until an AOD of ~0.25, due to the first indirect effect. At higher values of AOD, COD decreases with increasing AOD most likely to cloud absorption of solar radiation by black carbon and other absorbing aerosol particle constituents. This finding is important, since almost all models assume an increasing linear relationship between AOD and COD, whereas in reality, this does not occur. The study also found that AOD-COD relationships should be stratified by column water vapor in order to separate out differences in meteorology that might contribute to the relationships.
Future Activities:
For the next period of this project, we will continue working on several fronts. First, we will continue to expand the urban CO2 dome study to examine the relative contributions of heat release due to fossil-fuel combustion, heating due to urban surfaces (heat island effect), and heating due to CO2 domes to urban heating and air pollution health. Second, we will continue examining the effects of ethanol versus gasoline by simulating the aqueous oxidation of gas-phase byproducts of both, as determined by the largely-explicit Master Chemical Mechanism. Third, we will continue simulating the effects of gases and particles on current and future global climate with a particular emphasis on how such pollutants might impact the Arctic.Journal Articles on this Report : 12 Displayed | Download in RIS Format
Other project views: | All 66 publications | 23 publications in selected types | All 23 journal articles |
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Ginnebaugh DL, Liang J, Jacobson MZ. Examining the temperature dependence of ethanol (E85) versus gasoline emissions on air pollution with a largely-explicit chemical mechanism. Atmospheric Environment 2010;44(9):1192-1199. |
R833371 (2010) R833371 (Final) |
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Jacobson MZ. Short-term effects of agriculture on air pollution and climate in California. Journal of Geophysical Research 2008;113(D23):D23101 (18 pp.). |
R833371 (2008) R833371 (2009) R833371 (2010) R833371 (Final) |
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Jacobson MZ. On the causal link between carbon dioxide and air pollution mortality. Geophysical Research Letters 2008;35(3):L03809 (5 pp.) |
R833371 (2007) R833371 (2008) R833371 (2009) R833371 (2010) R833371 (Final) |
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Jacobson MZ. Effects of wind-powered hydrogen fuel cell vehicles on stratospheric ozone and global climate. Geophysical Research Letters 2008;35(19):L19803 (5 pp.). |
R833371 (2008) R833371 (2009) R833371 (2010) R833371 (Final) |
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Jacobson MZ, Streets DG. Influence of future anthropogenic emissions on climate, natural emissions, and air quality. Journal of Geophysical Research 2009;114(D8):D08118 (21 pp.). |
R833371 (2009) R833371 (2010) R833371 (Final) |
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Jacobson MZ. Enhancement of local air pollution by urban CO2 domes. Environmental Science & Technology 2010;44(7):2497-2502. |
R833371 (2010) R833371 (Final) |
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Jacobson MZ. Short-term effects of controlling fossil-fuel soot, biofuel soot and gases, and methane on climate, Arctic ice, and air pollution health. Journal of Geophysical Research 2010;115(D14):D14209 (24 pp.). |
R833371 (2010) R833371 (Final) |
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Jacobson MZ. Numerical solution to drop coalescence/breakup with a volume-conserving, positive-definite, and unconditionally stable scheme. Journal of the Atmospheric Sciences 2011;68(2):334-346. |
R833371 (2010) R833371 (Final) |
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Jacobson MZ, Ginnebaugh DL. Global-through-urban nested three-dimensional simulation of air pollution with a 13,600-reaction photochemical mechanism. Journal of Geophysical Research 2010;115(D14):D14304 (13 pp.). |
R833371 (2010) R833371 (Final) |
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Ketefian GS, Jacobson MZ. A mass, energy, vorticity, and potential enstrophy conserving lateral fluid-land boundary scheme for the shallow water equations. Journal of Computational Physics 2009;228(1):1-32. |
R833371 (2008) R833371 (2009) R833371 (2010) R833371 (Final) |
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Ketefian GS, Jacobson MZ. A mass, energy, vorticity, and potential enstrophy conserving lateral boundary scheme for the shallow water equations using piecewise linear boundary approximations. Journal of Computational Physics 2011;230(8):2751-2793. |
R833371 (2010) R833371 (Final) |
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Ten Hoeve JE, Remer LA, Jacobson MZ. Microphysical and radiative effects of aerosols on warm clouds during the Amazon biomass burning season as observed by MODIS: impacts of water vapor and land cover. Atmospheric Chemistry and Physics 2011;11(7):3021-3036. |
R833371 (2010) R833371 (Final) |
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Supplemental Keywords:
Global warming and health, future emissions, alternative-energy vehicles, numerical modeling., RFA, Scientific Discipline, Air, climate change, Air Pollution Effects, Environmental Monitoring, Ecological Risk Assessment, Atmosphere, air quality modeling, Baysian analysis, emissions impact, climate models, alternative fuel, atmospheric modelsRelevant Websites:
www.stanford.edu/group/efmh/jacobsonProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.