1.   At that southeast Valley location, a mix of agriculture and homebuilding contribute to high particulate levels.

2.   In contrast, a monitor in the pristine Organ Pipe National Monument in southwestern Arizona recorded particulate levels six or seven times lower than those in the urban area.

3.   Other researchers have recently reported elevated death rates in counties with high particulate levels, from diesel engines and other sources, and the institute is re-analyzing that data.

4.   One privately operated monitor in Houston also recorded an unacceptable particulate level at a station between downtown Houston and nearby Baytown late last week.

5.   Particulate levels Wednesday did not approach what they had been in previous days.

6.   Several studies have also shown that hospital admissions for heart problems also rise when particulate levels climb.

7.   Since January, there have been four cases when particulate levels exceeded federal health standards.

8.   So far this year, Valley particulate levels have exceeded healthful levels three times.

9.   The top Massachusetts particulate levels are in downtown Springfield, followed by Kenmore Square, Charlestown and Columbus Avenue in Boston, largely because of motor vehicle exhaust.