High temperatures and excessive heat at the end of last week kept many people indoors, but there was another reason to stay inside – ground-level ozone.

    Delaware was under its third code red ozone alert for the year on July 18 with an orange alert also issued for fine particulates.

    Air quality forecasts are issued throughout the summer to let the public know when air quality is unhealthy and how to take action on those days. The Delaware Valley Regional Planning Commission issues alerts on a scale of green, good; yellow, moderate; orange, unhealthy for sensitive groups; and red, unhealthy.

    “It’s when things get stagnant that pollutants build up, which is what is happening now,” said David Fees, Air Quality Management program manger within the Department of Natural Resources and Environmental Control, in a July 17 interview.

    State climatologist David Legates said any kind of air movement, whether a horizontal wind or thunderstorms, which create vertical movement, can help break up pollutants.

    Although many know more about the high altitude ozone that protects the Earth from the sun, people do have the understanding that ozone, or smog as it’s sometimes called, in the summer is a bad thing, Fees said. It forms in heat and sunlight when oxygen reacts with pollutants that originate from automobiles, power plants, construction equipment, farm tractors, or solvents in paint or gasoline.

    Going hand in hand with ozone pollution are fine particulates, which can combine for a hazy look, he said. The particulates in the air, which get a separate air quality forecast issued throughout the entire year, are found in smoke and haze and can come from forest fires or form from gases emitted from power plants, industries and automobiles, according the Environmental Protection Agency.

    When levels of either pollutant become too high, they pose a danger because they act as lung irritants, Fees said. According to the EPA, health problems that can develop are chest pain, coughing, throat irritation and congestion. Bronchitis, emphysema and asthma conditions also may be worsened.

    On red alert days all people are encouraged to stay indoors, although the best time to be outside is in the morning, Fees said, as the pollutants tend to build throughout the day and peak at approximately 3 to 6 p.m. before tailing off when the sun goes down. People also can limit activities that contribute to air pollution such as refueling their car in the morning before going to work or mowing the lawn.

    Delaware is a smaller part of the larger Delaware Valley air quality forecast area, which runs from north of Philadelphia and southern New Jersey to Sussex County. However, Fees said people should pay attention to alerts no matter where they live. Even if the Dover area isn’t red on a red alert day, it might still be high orange.

    So far, Fees said this year has been fairly typical for the number of orange and red air alerts with 13 orange- and three red-ozone alert days and three orange alerts for fine particulates.

    However, he said the EPA came out with lower thresholds for air quality this year, and the code red days may have been oranges last year.

    “The air isn’t getting worse, the standards are stricter,” Fees said.

    Alan Muller, executive director of Green Delaware, said the thresholds were lowered because as awareness of pollution grows people find more effects from pollutants.

    Individuals’ vulnerability to pollution seems to vary a great deal, he said. However, there’s no real way of keeping tack of the health problems that result from pollution.

    “An asthma attack doesn’t end up in a database,” he said.

    Muller and the Green Delaware organization send out email alerts to subscribers. He said he tries to let people know that air quality should be taken seriously along with the idea that more can be done to curtail pollutant levels.

    “The key message is that air pollution is a serious health hazard,” he said.

    People who are concerned about air quality also can sign up for email alerts from DNREC’s listserv or view the daily air forecast on its website, www.dnrec.delaware.gov/AQI/Pages/AQIFore cast.aspx.

    Email Jayne Gest at jayne.gest@doverpost.com.

Some easy ways to help clean the air:

• Ride DART First State. For more information, visit DART’s website at www.dartfirstate.com or call 800-652-DART.

• Carpool with friends and/or coworkers. For more information, call RideShare Delaware at 888-RIDE-MATCH or visit www.ridesharedelaware.org.

• Limit daytime driving and combine errands

• When driving, try to avoid congested periods

• Maintain your vehicle’s emission control equipment

• Walk or ride a bicycle for short, easy trips

• Postpone the use of gasoline-powered mowers until evening

• Refuel your car in the evening – and don’t top off the tank

• Avoid lighting your barbecue with starter fluid

• Avoid prolonged idling and jackrabbit starts

• Use latex rather than oil-based paints