NEAQS has been designed to provide a better understanding of:
- The role of long-range transport in shaping the air quality of New England. Although New England does have air pollution sources of its own, they are relatively modest in comparison to those in much of the rest of the United States. However, polluted air masses from the Northeast Corridor, the Midwest, and Southern Canada can significantly impact air quality in New England. A more predictive understanding of the role of long-range transport will serve to guide more effective management strategies while enhancing the overall understanding of the processes that control the formation and distribution of air pollution.
The role of biogenic emissions in local and regional New England air quality. Ozone is formed in the atmosphere through a complex series of reactions involving volatile organic compounds (VOCs) and nitrogen oxides (NOx) in the presence of sunlight. The abundant forests of New England are a significant source of reactive (VOCs) that contribute to the production of ozone and the formation and growth of fine particles. Intensive field campaigns conducted by NOAA in the Midwest and Southeast have demonstrated the important role that biogenic VOCs can play in pollution formation. However, this work has focused on isoprene, which is emitted from southern deciduous forests. The ozone- and particle-producing properties of pinenes and other terpenoid compounds emitted by the coniferous forests of the North are very different than those of isoprene (e.g., temperature). The impact of these natural emissions on regional air quality is not well understood.
- What are the relative contributions of local and distant sources?
- What source regions are most important?
- What is the role of nighttime chemistry and transport?
- How does transport and chemistry in the marine boundary layer alter the pollutant mix?
The role of the sea-breeze/land-breeze (SBLB) circuit in influencing New England air quality. The sea-breeze/land-breeze circuit (SBLB) is a meso-scale circulation of air caused by the differential heating and cooling of the land- and sea-surfaces in the coastal zone. It is driven by the diurnal cycle of solar insolation and the differing heat capacities of land surfaces and seawater. The SBLB phenomenon has the potential to profoundly effect New England's air quality. Re-circulation of polluted air between the coastal marine and eastern New England coastal areas is evidenced by the ozone episodes shown in Figures 4 and 5. The chemical processing of continental air in the local marine environment could, for example, substantially alter its reactive nitrogen content. This processing could subsequently influence the photochemical state and ozone production potential of the polluted air parcels. These processes are known to involve complex heterogeneous chemistry, which need to be studied in detail.
- What are the relative contributions of man-made and natural (i.e., from forests) VOCs to ozone and fine particle formation and growth?
- What role do natural VOCs play in nighttime chemistry?
Capabilities of current air quality forecasting systems. Air quality forecasts are currently being performed for all of the major metropolitan areas of the U.S. EPA collects and displays ozone forecasts for U.S cities at AIRNOW. The methods used to produce these forecasts vary from relative simple climatological approaches to the application of sophisticated photochemical grid models5. The need for reliable air quality forecasts is clear and growing. However it is important to continuously evaluate the skill of the techniques to select the most suitable approach for each application and to improve the skill of the techniques being employed.
- When and where is the SBLB important?
- What chemical processing of polluted air occurs in the coastal zone?
Linkages between air quality and climate. The meteorological conditions that promote adverse air quality in New England are tightly coupled to the climate systems. The relative frequency of air mass stagnation, the development of shallow inversion, which lead to "home-grown" pollution events and transport patterns that bring pollution from the industrial Midwest and urban areas along the East Coast determine the quality of the air to which the citizens of the region are exposed. Also, the polluted air that leaves New England can ultimately influence air quality in Eastern Canada and ultimately the North Atlantic and Europe. A better understanding of the linkages between climate and air quality is needed if we are to be able to reliably predict the influence of predicted changes in climate on future air quality.
- How well do current air quality forecast models predict ozone fields (operational evaluation)?
- How well do these models reproduce the observed chemistry and meteorology (diagnostic evaluation)?
- What improvements in model design or operation are needed to significantly improve forecast skill?
- Which synoptic patterns are associated with high pollution events in New England?
- How much of the air pollution in the region is transported to the North Atlantic and the free troposphere?