DaytonDailyNews.com

An air pollution advisory issued Thursday for Clark, Greene, Miami and Montgomery counties has been extended through today as high levels of particle pollution are expected to continue this afternoon.

Particle pollution is made up of microscopic particles and liquid droplets in the air. These particles, invisible to the naked eye, appeared collectively as the fog-like haze visible over most the Dayton area Thursday.

The particles can get deep into the lungs to cause chronic bronchitis or worsen conditions such as asthma, emphysema and heart disease. The elderly, small children and those suffering from heart or lung disease are considered at greater risk from the particles.

"It puts you at risk of developing allergy problems down the road," said Dr. Salman Razi, a pulmonologist at Kettering Medical Center. He said people with pulmonary or heart conditions should avoid going outdoors as much as possible on days when air quality is poor.

If you must venture outdoors, he advised staying well hydrated and avoiding overexertion through prolonged exercise. Exercise or strenuous physical activity causes faster and deeper breathing, allowing more particles into the lungs.

Razi recommended taking daily workout indoors when the air quality index is high.

"Maybe go to the local mall or grocery store and do your walking there," he said.

The Regional Air Pollution Control Agency, which serves Clark, Darke, Greene, Miami, Montgomery and Preble counties, issues air pollution advisories whenever the air quality index is projected to reach unhealthy levels.

Brian Huxtable, an air pollution control specialist for the agency, said an air quality index of 90 or above is cause for an advisory.

Thursday's index was 125 for particle matter, an amount designated by the Environmental Protection Agency as unhealthy for sensitive groups. An index of 151 or above is considered unhealthy for everyone.

Mike Ryan, a National Weather Service meteorologist in Wilmington, said the warm layer of air above the Miami Valley this week has caused the buildup of particle pollution we see as smog.

"We're also seeing some of the smoke from fires in the southeast," he said.

For the Memorial Day weekend, expect to see chances of showers and thunderstorms daily through Monday, mostly in the evenings, according to the weather service. Temperatures should reach into the 80s today and Saturday, the upper 70s Sunday and Monday. Lows are expected to be in the 60s.

Staff writer Ryan Fox contributed to this report. Contact the reporter at kwedell@coxohio.com.

To cut pollution

Reduce driving: Try to walk, bike or carpool. Combine errands to cut down on driving time.

Avoiding idling: Idling at the drive-thru or in a parking lot wastes gas and creates concentrated emissions.

Maintain regular maintenance: A well-tuned engine runs more efficiently.

Cut down on use of gas-powered appliances: Gas-powered mowers and chainsaws emit emissions. Running a mower one hour creates as much pollution as driving a car 350 miles. It's best to use these devices only after 6 p.m.

Eliminate outdoor burning: Do not burn yard waste or trash outdoors.

Fill up properly: Avoid spilling gas when filling your vehicle and make sure the gas cap is on tight.