1. CHARGE QUESTIONS: ENDPOINTS  anthropogenic emissions   air pollution   climate OK, but can we be more specific?  Intercontinental transport of air pollution: –Focus on O3 and PM, how about the rest (Hg, POPs,…?) –Air quality standards – focus on present standards or anticipate future? Climate change from air pollutants –Is radiative forcing the appropriate metric? –Should we focus on regional (as opposed to global) aspects of climate change? Integrated assessments of  air pollution and  climate –Is integration of these two foci a short-term priority? –At what point do we need to bring in an economic perspective? We want to better understand the relationship

2. CHARGE QUESTIONS: EMISSIONS What improvements are needed in emission inventories? –Regions: Developing world, megacities –Processes: vehicles, industry, ships, biofuels, biomass burning, natural (wild fires, vegetation/soils, lightning), unconventional sources –New species: CH4, NH3 –Fingerprinting emission vectors from specific sources –Future emission scenarios: IPCC, CLRTAP, climate-driven changes

3. CHARGE QUESTIONS: PROCESSES What key improvements are needed in the model simulation of aerosol and chemical processes? –Aerosol microphysics  radiative properties –Aerosol-cloud interactions –Heterogeneous chemistry –Hydrocarbon chemistry

4. CHARGE QUESTIONS: MODELS What kinds of models are needed –For intercontinental transport of pollution? –For climate forcing by air pollutants? Nested regional/global models (1-way, 2-way) Coupled aerosol/chemistry/climate models Model intercomparisons What kind of observations are needed to evaluate these models? –In situ observations: surface networks, aircraft, field missions –Satellite observations: low-elevation and geostationary orbits –Integrate models into observational strategy

5. PRIORITY QUESTIONS AND STRATEGIES FOR PHASE II (in order) 1.How will changing anthropogenic emissions outside North America enhance background ozone and PM concentrations in the U.S., and the ability of the U.S. to meet the NAAQS? Need improved 2000 global, gridded emission inventories for ozone and PM precursors partitioned by source sector Need policy-relevant 2020 emission projections Need nested global  regional model 2.How will changes in emissions of PM, PM precursors, and ozone precursors, in the U.S. and in the rest of the world, contribute to climate change? Need GCM calculations forced by realistic emission projections 3.How do U.S emissions affect the ability of countries in Europe and Asia to meet their air quality objectives?

6. DISCUSSION Examine exposure of population to NAAQS violations Use atmospheric observations to constrain emissions, esp. episodic emissions Encourage interagency collaboration models/observations Future emission projections should be policy-relevant Intercontinental transport of PM – need good models. Dust is particularly difficult. Natural vs. anthropogenic vs. climate-driven dust. Satellite observations need to be exploited. Link global impacts of emissions from countries outside N America to their own regional air quality objectives Assessing health effects in other countries will require finer-scale models than we can achieve within the global/regional focus of the program Episodes seen from satellites can be important for providing “real evidence” of intercontinental transport

7. DISCUSSION (cont.) Can we assess climatic impacts of air pollutants for different scenarios without running long-term GCM simulations –Need GCMs to get regional impacts of inhomogeneous forcing from ozone and PM –Simple radiative forcing is still useful –Tropics are particularly important in driving climate: need to know effect of northern midlats pollution on tropics –Regional climate change difficult to predict Capability limited by resolution / computer power Emission controls on PM in different continents would elicit different regional responses (e.g., monsoons) also would affect global forcing because of the different forcings from different aerosol types. Need to define a limited set of priority scenarios for full GCM simulations, use results to interpolate to range of other scenarios.

8. DISCUSSION (cont.) Better define policy questions focused on PM, CH4, O3 to guide what simulations need to be done. –Need better knowledge of interrelationship between emissions –Focus on sensitivity of the system –Need to figure out if current EPA emission control strategies directed at regional air quality need to be revised – bring in methane, less reactive VOCs, fires, etc… Radiative forcing and climate response –Climate response needs ensemble of simulations – five OK, more better –Detail of processes vs. # simulations. –Dealing with detailed microphysics is an innovative feature of present program –Need both GCMs with detailed aerosol microphysics (small ensemble) and GCMs with simple aerosols (large ensemble)

9. DISCUSSION (cont.) Need to figure out how to linearize climate response to perturbations – works for small forcings How can we increase computing resources for the climate response simulations? Going to Phase III –Resolving small-scale processes outside North America Heterogeneous chemistry and other small-scale processes Health effects outside N America –Using satellite observations MODIS, MISR: fires, land-use; present NASA focus is on global scale Get information on land cover at urban scales Particularly valuable for fires Focus on improving emission estimates using space- based observations. –Better define errors and error covariances in bottom-up emission inventories for top-down inversion analyses. –Support for INTEX: Emission inventories (next anchor year in 2002 including Canada), ground-based sites, continuous emission monitors on power plants are available but need to make the data more accessible.

10. DISCUSSION (cont.) Phase III (cont.) –Observational evidence for intercontinental transport; exploit data from NOAA 2K2 mission. Can we get observational evidence for intercontinental influence on the PM background? Use IMPROVE data –Don’t argue that intercontinental transport is critical to the PM NAAQS, but the delta-PM associated with intercontinental transport can be highly relevant to health effects –Large fires outside N America are of great concern –What is the anthropogenic influence on dust emission? –Does CMAQ have the ability to address future scenarios