Development of a United States–Mexico Emissions Inventory for the Big Bend Regional Aerosol and Visibility Observational (BRAVO) Study

225

186

The Regional Haze Rule of the US Environmental Protection Agency mandates reduction in US anthropogenic emissions to achieve linear improvement of visibility in wilderness areas over the 2004-18 period toward an endpoint of natural visibility conditions by 2064. Linear improvement is to apply to the mean visibility degradation on the statistically 20% worst days, measured as a Haze Index in units of deciviews (log of aerosol extinction). We use a global chemical transport model (GEOS-Chem) with 11 Â 11 horizontal resolution to simulate present-day visibility statistics in the USA, compare them to observations from the Interagency Monitoring of Protected Visual Environments (IMPROVE) surface network, and provide natural and background visibility statistics for application of the Regional Haze Rule. Background is defined by suppression of US anthropogenic emissions but allowance for present-day foreign emissions and associated import of pollution. Our model is highly successful at reproducing the observed variability of visibility statistics for present-day conditions, including the low tail of the frequency distribution that is most representative of natural or background conditions. We find considerable spatial and temporal variability in natural visibility over the USA, especially due to fires in the west. A major uncertainty in estimating natural visibility is the sensitivity of biogenic organic aerosol formation to the availability of preexisting anthropogenic aerosol. Background visibility is more variable than natural visibility and the 20% worst days show large contributions from Canadian and Mexican pollution. Asian pollution, while degrading mean background visibility, is relatively less important on the worst days. Recognizing the influence of uncontrollable transboundary pollution in the Regional Haze Rule would substantially decrease the schedule of emission reductions required in the 2004-18 implementation phase. Meaningful application of the Rule in the future will require projections of future trends in foreign anthropogenic emissions, wildfire frequency, and climate variables. r

“…Kuhns et al (2005) found that the BRAVO Mexican SO 2 emission inventory used in our work is lower by 30% than the 1999 Mexican National Emission Inventory (NEI) (ERG, 2003).…”

Section: Present-day (Baseline) Visibility Statisticsmentioning

confidence: 55%

Section: Model Descriptionmentioning

confidence: 61%

Regional visibility statistics in the United States: Natural and transboundary pollution influences, and implications for the Regional Haze Rule

Park

Jacob

Kumar

et al. 2006

225

186

“…Global anthropogenic emissions are from the Global Emission Inventory Activity (GEIA), scaled to 1995 as described by Bey et al (2001). This is overridden in the US with the EPA National Emission Inventory (NEI) for 1999, in northern Mexico with the Big Bend Regional Aerosol and Visibility Observational (BRAVO) inventory for 1999 (Kuhns et al, 2005) and in Canada with the Environment Canada Criteria Air Contaminants (CAC) inventory for 2002 (http://www.ec.gc.ca/pdb/ cac/cac_home_e.cfm). Emissions in US-Canada and US-Mexico border grid squares are the sums of the two corresponding national inventories.…”

Section: Model Descriptionmentioning

confidence: 99%

Surface ozone background in the United States: Canadian and Mexican pollution influences

Wang

Jacob

Sager

et al. 2009

a b s t r a c tWe use a global chemical transport model (GEOS-Chem) with 1 Â 1 horizontal resolution to quantify the effects of anthropogenic emissions from Canada, Mexico, and outside North America on daily maximum 8-hour average ozone concentrations in US surface air. Simulations for summer 2001 indicate mean North American and US background concentrations of 26 AE 8 ppb and 30 AE 8 ppb, as obtained by eliminating anthropogenic emissions in North America vs. in the US only. The US background never exceeds 60 ppb in the model. The Canadian and Mexican pollution enhancement averages 3 AE 4 ppb in the US in summer but can be occasionally much higher in downwind regions of the northeast and southwest, peaking at 33 ppb in upstate New York (on a day with 75 ppb total ozone) and 18 ppb in southern California (on a day with 68 ppb total ozone). The model is successful in reproducing the observed variability of ozone in these regions, including the occurrence and magnitude of high-ozone episodes influenced by transboundary pollution. We find that exceedances of the 75 ppb US air quality standard in eastern Michigan, western New York, New Jersey, and southern California are often associated with Canadian and Mexican pollution enhancements in excess of 10 ppb. Sensitivity simulations with 2020 emission projections suggest that Canadian pollution influence in the Northeast US will become comparable in magnitude to that from domestic power plants.

“…The fossil fuel emissions are from the Emission Database for Global Atmospheric Research (EDGAR) inventory for NO x , CO, and SO 2 and from the Global Emission Inventory Activity (GEIA) for other chemical compounds (Benkovitz et al, 1996;Olivier and Berdowski, 2001). These emissions are updated with particular national emission inventories and fuel use data: the Big Bend Regional Aerosol and Visibility Observational Study (BRAVO) inventory for Mexico (Kuhns et al, 2005) and U.S. EPA NEI 99 inventory (National Emissions Inventory, base year 1999, version 3) for the continental U.S. (EPA, 2004). The biogenic VOCs emissions are based on the Model of Emissions of Gases and Aerosols from Nature (MEGAN) inventory (Guenther et al, 2006).…”

Section: Geos-chem Is a Global 3-d Chemical Transport Model Driven Bymentioning

confidence: 99%

Satellite observations of Mexico City pollution outflow from the Tropospheric Emissions Spectrometer (TES)

Shim

Luo

et al. 2009

a b s t r a c tConcurrent tropospheric O 3 and CO vertical profiles from the Tropospheric Emission Spectrometer (TES) during the MILAGRO/INTEX-B aircraft campaigns over the Mexico City Metropolitan Area (MCMA) and its surrounding regions were used to examine Mexico City pollution outflow on a regional scale. The pollution outflow from the MCMA occurred predominantly at 600-800 hPa as evident in O 3 , CO, and NO x enhancements in the in situ aircraft observations. TES O 3 and CO are sensitive to the MCMA pollution outflow due to their relatively high sensitivities at 600-800 hPa. We examined O 3 , CO, and their correlation at 600-800 hPa from TES retrievals, aircraft measurements, and GEOS-Chem model results. TES captures much of the spatial and day-to-day variability of O 3 seen in the in situ data. TES CO, however, shows much less spatial and day-to-day variability compared with the in situ observations. The DO 3 /DCO slope is significantly higher in the TES data (0.43) than the in situ data (0.28) due partly to the lack of variability in TES CO. Extraordinarily high DO 3 /DCO slope (0.81) from TES observations at 618 hPa over the Eastern U.S. was previously reported