No Ozone Advisory is in effect until at least 4 p.m. on Friday for the Front Range Urban Corridor from El Paso County north to Larimer and Weld counties, including the Denver-Boulder area, Colorado Springs, Fort Collins and Greeley.

High based thunderstorms will keep ozone levels in the good-to-moderate range this afternoon and evening.

The highest Ozone related AQI at 1 o'clock AM Mountain Standard Time on August 13, 2009, is 48 which indicates Good ozone air quality. It was recorded by the AURE ambient ozone monitor

Should atmospheric conditions suggest increased ground-level ozone concentrations, the Colorado Department of Public Health and Environment and the Regional Air Quality Council will issue an ozone advisory. Check this website (http://colorado.gov/airquality/advisory.aspx) often for a report on current air quality conditions and to learn if an ozone action day alert is in effect.

Thursday, August 13, 2009, 3:30 PM: FRONT RANGE AIR QUALITY FORECAST: Ozone is expected to climb into the Moderate range in many areas during the afternoon and evening on Thursday. Consequently, unusually sensitive people should limiting prolonged outdoor exertion between the hours of 3 PM and 11 PM today. Visibility is expected to be in the Moderate-to-poor range Friday. Smoke from wildfires in western Colorado and western states is expected to contribute to haze in Colorado, including eastern Colorado. Fine particulate matter and carbon monoxide are expected to remain in the Good category in the Front Range. COLORADO SMOKE OUTLOOK: Fires in western Colorado and nearby western states will produce light smoke across much of Colorado, but haze from low concentration levels of smoke is not expected to be a significant health concern. However, in areas of western Colorado near fires, moderate to heavy smoke is possible. Moderate to heavy smoke is possible in the immediate vicinity of fires and in canyons, valleys and drainages downstream of the fires during the nighttime and morning hours. In southwest Colorado, moderate to heavy smoke is possible in the vicinity of the Narraguinnep Fire about 12 miles southeast of Dove Creek in Dolores County in southwestern Colorado. IF VISIBILITY IS LESS THAN 5 MILES IN SMOKE IN YOUR NEIGHBORHOOD DUE TO A WILDFIRE OR CONTROLLED BURN, SMOKE HAS REACHED LEVELS THAT ARE UNHEALTHY. If smoke is thick or becomes thick in your neighborhood you may want to remain indoors. This is especially true for those with heart disease, respiratory illnesses, the very young, and the elderly. Consider limiting outdoor activity when moderate to heavy smoke is present. Consider relocating temporarily if smoke is present indoors and is making you ill.

For an AQI value that considers all pollutants, please click here.

Ground-level ozone is a summertime air pollution problem that is created when other pollutants from sources like vehicle exhaust, paints, degreasing agents and cleaning fluids react with sunlight. Exposure to ground-level ozone can cause acute respiratory problems, reduced lung capacity and inflammation of lung tissues and can trigger asthma attacks.

Ground-level ozone should not be confused with the protective stratospheric ozone layer miles above the Earth's surface. This naturally-occuring ozone layer protects the Earth's surface from excessive ultra-violet radiation.

Do your share and be a part of the solution to the Denver-metropolitan area's summertime air pollution problems. These easy strategies will help reduce the harmful vapors that react in sunlight to create summertime air pollution:

At Home:

• Tightly cap all solvents (paint thinners and strippers, degreasers, and some cleaning products). Solvents contain pollution-causing vapors.
• Postpone painting, stripping and refinishing projects to avoid the morning and mid-day summertime heat. Better yet, wait until the Fall or Spring.
• Use water-based products (paints, stains and sealants).

In the Yard:

• Delay mowing your lawn to another day. Don't mow, let it grow!
• Avoid using high-emitting, gasoline-powered yard equipment. Electric alternatives are an efficient, environmentally-friendly alternative.
• Use an electric starter or a "charcoal chimney" to start your barbeque grill. Lighter fluid contains a lot of harmful vapors that escape into our air and contribute to summertime air pollution.

On the Go:

• Stop at the click when refueling your car. Overfilling your tank often results in fuel spills and always allows unnecessary pollution-causing vapors to escape into our air.
• Refuel in the evenings after dusk. By refueling after the sun goes down, fuel vapors do not have as much of a chance to "cook" in the mid-day sun and become harmful ground-level ozone.
• Maintain your vehicle. A poorly-maintained vehicle can pollute as much as 25 times more than a well-maintained one.

For more information about ground-level ozone and what you can do to help take care of your summer air, visit http://www.ozoneaware.org/