The Board of Health passed a resolution this week instructing the City-County Health Department to notify the Alpine and Provo school districts when fine particulate pollution measures 200 or more in a one-hour reading at the Lindon Air Quality monitor.

The districts will be advised to keep children attending schools in Provo, Orem, Lindon and Pleasant Grove indoors because of the health hazard posed by pollution levels."It's a request, not a requirement," said Ralph Clegg, supervisor of the county's vehicle emission program.

However, it's a request that should be taken seriously. Fine particulate matter less than 10 microns in diameter (PM10) is capable of penetrating lung tissue and causing permanent damage. The pollutant poses a particular risk to the very young, the very old and to people with existing health problems.

"Kids are quite active when they go outdoors, and if pollution is high it could have an impact on them," Clegg said.

Although the PM10 standard is based on a 24-hour average reading, the one-hour reading the health department will use, measured between 8 a.m. and 9 a.m., is a good predictor of when the standard will be violated.

"When it's over 200 early in the morning, it usually remains high and we're probably going to have 24-hour average over 150," Clegg said.

Since the beginning of the year, early morning readings of 200 or more have been measured at the Lindon monitor on seven occasions. On Feb. 7, the hourly average between 8 a.m. and 9 a.m. was 272. Between 9 a.m. and 10 a.m., it rose to 300 micrograms. The 24-hour average for that day was 197, above the standard of 150.

On Feb. 10, the Lindon monitor recorded a one-hour reading of 400 during the noon hour.

There have been as many as five days since the first of the year when the 24-hour standard was violated but early morning readings were not above 200, Clegg said. Still, the health board decided the one-hour morning reading was the best indicator of what pollution levels would be for a particular day.

The health department will notify schools this year if pollution levels warrant it; however, it is likely the program will not begin until next winter because the pollution season (November to February) is almost over.