Press Release

Baltimore, MD (May 1, 2008) – The Maryland Department of the Environment (MDE) will resume daily ozone (and continue fine particle) air quality forecasts today based on new, more stringent federal ozone standard that could result in substantially more air quality alerts across Maryland this summer.

Air quality forecasts will resume across the state as the ozone season gets underway. Forecasts will be based on two new air quality standards adopted by the U.S. Environmental Protection Agency (EPA):

  • The 8-hour ozone standard of 75 parts per billion (ppb) that the EPA adopted in March 2008, replacing the old standard of 85 ppb that had been in effect since 1997.
  • The 24-hour fine particle standard of 35 micrograms per cubic meter (µg/m³) that the EPA adopted in September 2006, replacing the old standard of 65 µg/m³.

The daily air quality forecasts focus on the air pollutant likely to reach the highest Air Quality Index (AQI) level on a given day, which could be ozone or fine particle pollution. The color-coded forecasts show whether air quality is likely to be Good (Green), Moderate (Yellow), Unhealthy for Sensitive Groups (Orange), or Unhealthy (Red). Preliminary analyses by MDE show that Maryland could have at least twice as many exceedence days as compared to the old standards.

"Maryland will continue to take steps to reduce ozone from local and out-of-state sources" said MDE Secretary Shari T. Wilson. "The ozone standard has been lowered so we expect to see more code Orange and Red days. It will be important for all of us to take steps on "ozone action days" to reduce our contributions to this problem - refuel after dark, postpone using gas powered lawn mowers and combine errands to reduce car trips."

Meteorologists at MDE issue the air quality forecasts at 3 p.m. every day for the following three days. On Code Orange and Red days, the forecasts also suggest actions that people can take to protect their health (e.g., limiting activity outdoors and outdoor exertion) and reduce air pollution (e.g., avoid driving and use transit, refuel after dark, avoid using gas powered lawn equipment, etc.).

Ozone is Maryland’s most widespread air quality problem, particularly during the warmer summer months. High ozone levels generally occur on hot sunny days with little wind, when pollutants such as Nitrogen Oxides (NOx) and Volatile Organic Compounds (VOCs) react with heat and sunlight. In addition, fine particles also pose an air quality problem for Maryland citizens. Unlike ozone fine particles are a year-round problem and can either be directly emitted into the air or may form under a chemical process much the way ground level ozone forms.

Ozone, a highly reactive form of oxygen, can be unhealthy to breathe -- particularly for children, people with respiratory problems or heart disease, and even healthy adults who work or exercise outdoors. Exposure to high ozone levels may cause previously healthy individuals to develop asthma over time. Ozone also causes millions of dollars in tree and crop damage each year. More than half of Maryland’s residents live in counties where ozone levels periodically exceed the standard.

Fine particle pollution, which consists of very small particles and liquid droplets in the air, can be harmful to breathe and contributes to haze and other air quality problems. Fine particles can penetrate deeply into the lungs and absorb into the bloodstream, causing or aggravating heart and lung diseases. Persons most susceptible to fine particle pollution include those with heart and respiratory conditions, the elderly and young children. Unlike ozone, which is usually highest in the afternoons, fine particle levels can be high at any time of the day. Sensitive groups should take special care to limit their physical activity during high fine particle periods.

Maryland has taken a number of successful steps to reduce levels of ozone, fine particles and other air pollutants in recent years. Maximum average ground-level ozone in Maryland decreased by approximately 17 percent between 1990 and 2007. The General Assembly enacted the Clean Cars Act to reduce pollution from cars and the Healthy Air Act to reduce air pollution from power plants. In addition, MDE requires emitters of air pollutants to be permitted and requires documentation to ensure that emitters are complying with Maryland laws.

The MDE will develop a plan to meet the new standards that will include new local controls and continue to push for controls in upwind states that export pollution to Maryland. Research by MDE shows that “incoming” ozone levels, on bad days, already exceed the new standard.

Citizens can obtain air quality information and forecasts.

Citizens can obtain fact sheets relating to the new ozone standard and the revised AQI.