Pollution advisory in effect Thursday as temperatures climb

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PHOENIX -- Another warm day is ahead as a ridge of high pressure dominates our weather pattern. Look for light winds, plenty of sunshine and desert highs near 100 degrees today through Saturday.

Early next week, a storm pushes by to our north, and afternoon high temperatures come back down to the 80s. 

Today's combination of sunshine, heat and light winds has prompted a High Pollution Advisory for the Valley. 

The Arizona Department of Environmental Quality has more details in this message from their website:

…AN OZONE HIGH POLLUTION ADVISORY HAS BEEN ISSUED FOR THURSDAY, MAY 5, 2011…

"A very strong area of high pressure over the region will send afternoon desert temperatures into the upper 90s to around 102 degrees F in the hottest locations through Saturday. Winds will remain mostly light during the next few days. This lack of air flow in the Valley will promote a significant increase in ground-level ozone. Though some of the precursors may have been imported from southern California over the past several days, this episode will primarily be home-grown. Concentrations may approach the health standard in some spots of the west, central and north part of the Valley Wednesday. On Thursday, we expect several monitors to exceed that standard. As a result, an Ozone High Pollution Advisory has been issued for Thursday.

"The return of a slight west-to-east flow across the forecast area on Friday may help to alleviate some of the accumulating pollution. This should result in lower ozone levels on Friday and Saturday.

"As far as particulates go, monitors continue to remain in the GOOD range of the Air Quality Index (AQI). There was an unusual spike in PM10 and PM2.5 levels this morning around 6 a.m. at the Durango monitor, but levels have subsequently declined. Little change in overall Valley PM10 and PM2.5 concentrations is expected the next several days as winds remain very light across the region."

What causes ozone pollution?

Ground-level ozone, which is a colorless gas, is caused when pollutants from cars, gas-powered lawn mowers, paint and similar items mix with heat and sunlight. Ozone levels are highest during the hot summer months.

The resulting bad air, can exacerbate heart ailments and respiratory issues, including asthma and and chronic lung conditions like COPD.

Health officials say residents can help the situation by carpooling, taking the bus and running errands early in the morning or late in the evening.