Investment in the development of new emissions-monitoring techniques (for example, continuous emission monitors for a wider number of sources) to better characterize actual emissions.
Improvement in current and projected mobile-source emission inventories through expansion of the in-use emission measurement program for on-road vehicles and the various categories of off-road mobile sources.
Development of better source signatures to facilitate an assessment of the quality of the emission data by source category, using, for example, chemical and isotopic tracers.
A systematic program of applying the best available emissions measurement and characterization technologies to develop emission factors for every major class of sources.
Investment in more comprehensive efforts to develop, maintain, and regularly update source inventories.
Independent efforts, using ambient as well as emissions data, to validate and improve models used in emission inventories.
Continuous efforts to track the adequacy of emission inventories by reconciling the inventories with ambient measurements.
Incorporation of more formal uncertainty analysis, based on the validation efforts, in the presentation and use of inventories.
The Emission Inventory Improvement Program, initiated by EPA and the State and Territorial Air Pollution Program Administrators and Association of Local Air Pollution Control Officials, is one example of such efforts that should be vigorously implemented and enhanced to more fully address important shortcomings of the current system.
Increasingly complex air quality challenges require a substantially improved multipollutant air quality monitoring system. An effort should be made to ensure that air quality monitoring systems are capable of meeting the increasingly complex challenges and diverse objectives for monitoring in a risk- and performance-oriented AQM system with maximum efficiency. A detailed list of suggested improvements is included in Chapter 6 and Appendix D. The following needs are among the highest priority needs for optimization of the nation’s monitoring network:
A comprehensive review of the various air quality monitoring programs to develop an integrated monitoring strategy that incorporates appropriate measurements of pollutants and their precursors. This review should consider shifting resources. An integrated monitoring strategy should improve the ability of the system to address the objectives that have