AQ ApplicationsA top-down picture of the usefulness of satellite observations in termsof air quality regulatory and technical support requirements can besummarized. The air quality requirements4 are• determination of compliance with the ambient air quality standards,• inference of human and ecosystem exposure,• identification of intra- and intercontinental events relevant to EE,• establishment of trends in ambient concentrations relevant to accountability,• regulatory and forecast model applications, and• extension of fundamental knowledge relevant to air quality.Each of these topics is important to air quality management, and eachhas detailed technical issues associated with spatial and temporalresolution, accuracy, and precision, etc.
EmissionsSatellite-based estimation of emissionscomplement bottom-up inventories by – Improving poorly characterized and growing regions such as China and India – Quantifying the ‘natural’ aerosol emissions from windblown dust, biomass smoke; NOx from lightning and soil; VOCs form biogenic activities. Included in emission processing for CMAQ Model ‘validation’ Unique Contribution: NAAPS – Emissions by Sat- Assimilation
Long Range TransportSatellites can characterize/quantify LRTP• Detection of transport events (natural & anthropogenic)• Quantify fluxes• Improved characterization modelsUnique contribution: CMAQ - NAAPS Sat-Assimilation
RECOMMENDATIONSInvestigators should be encouraged to forward• increased interaction between the various measurement communities; air quality and and remote sensing scientists working more closely• facilitate the utility of a comprehensive portfolio of measurements• adjunct analyses approaches for improved air quality applications.Can near-term satellite observations play a role in characterizing broad based(outdoor) exposure to pollutants and consequently influence public healthimprovement? and, if so, then,What comprehensive, integrated system is needed if satellite observations are to beused together with ground based observations and modeling to continue improvingair quality management options?
CONCLUSIONSGround-based PM (mass) concentration measurements, as operated in EPA’s AirQuality System (AQS) network and other agency ground networks, measure at a pointin situ, ambient PM (PM2.5 and PM between 2.5 and 10 um [PM10–2.5]) massconcentrations. These observations characterize urban and nonurban conditions onspatial scales much less than the pixel averages from aloft.AOD measures of PM, by themselves, cannot be used to underpin regulatory AQSforecasting because AOD column abundance cannot be quantitatively verified to equalground PM concentrations. Unless the vertical structure of the AOD can beconstrained, and atmospheric boundary layer composition extracted, themeasurement cannot be assured to represent PM at the surface.The uncertainty in the relationship between remotely sensed and surfaceconcentration measurements is too high for application to regulatory requirements orpublic health warnings (??).