Ozone formation in rural areas causes a significant stress on our nation's agriculture and forest industries. For example, recent estimates suggest that a 25% reduction in ozone levels would yield increased crop production in excess of $2 billion per year. In addition, ozone is a significant stress to ecosystems in many of our national parks and wilderness areas. Ozone is formed from volatile organic compounds (VOCs) and nitrogen oxides in the atmosphere. In urban areas, these compounds are emitted primarily by human activities; hence, control strategies must be tied to those activities. In rural areas, however, VOCs are largely contributed by vegetation. Nitrogen oxide control strategies may therefore be the most effective way to combat high ozone levels in rural areas.
Federal, state, and local agencies are cooperating in studies to monitor and model ground-level ozone, especially in rural areas. The CAAAs can be formulated and implemented more effectively when we understand the processes involved, the regions of the country affected, and the effects of reducing VOC or nitrogen oxide emissions on ground-level ozone formation.
The NADP was created under the leadership of the State Agricultural Experiment Stations. During the 1980s, NAPAP integrated its new National Trends Network with the NADP network to provide a better picture of deposition patterns. The network has documented national trends in precipitation chemistry for over 15 years and now consists of approximately 200 stations nationwide, providing an unprecedented long-term index of our nation's air quality. Time series of observations of this nature and duration are exceptionally rare in the environmental sciences.
This deposition record will continue to document what's coming down and will become even more valuable as the record gets longer. In combination with complementary new stations being planned for monitoring air concentrations of key pollutants, these time series will reveal what's changing and, perhaps more importantly, why. With insights from regional field campaigns and more descriptive theoretical models, the United States will gain improved predictive capabilities for managing air quality.