Extreme Dust and Smoke Events Over the U.S. in 1998
Dust storms and forest fires are major PM events that occur several times a year over different parts of the US. Such events also originate outside the US, e.g., dust from Sahara and the Asian deserts and smoke from forest fires in Central America and Canada. Such dust and smoke events, and the exceedances of the NAAQS which they cause, cannot be controlled by State Air Quality (AQ) management agencies. However, such agencies are required to provide evidence that the events originated outside their jurisdiction. Hence, there is a need to detect and document the origin of such events and their imnpact in the area of concern. The existing tools for such documentation are poorly developed. These natural PM events will be illustrated by two extreme examples from 1998. Asian dust and Central American forest fire smoke.