Poor air quality posed a health hazard in the Baltimore area yesterday and was likely to reach unhealthful levels again today, the Maryland Department of the Environment said.
The department issued a "code red" health advisory for Baltimore City and Anne Arundel, northern Harford and northern Cecil counties yesterday.
Under a "code red," children and elderly people are advised to limit outdoor activities; healthy people to limit strenuous outdoor work or exercise; and people with heart or respiratory ailments, emphysema, asthma or chronic bronchitis to limit outdoor activities and move indoors when breathing becomes difficult.
Residents also were advised to limit driving, use bus and rail lines, avoid mowing lawns with gasoline-powered mowers, refuel cars after dark and listen for air quality updates.
A code red means high levels of dangerous ground-level ozone was recorded.
Ground-level ozone can cause lung damage, eye irritation, breathing difficulties, coughing and chest pains.
Ozone, a colorless and odorless gas, is considered the Baltimore region's worst air quality problem.