July 09, 2018
Elevated ozone levels could pose respiratory issues for residents of Southeastern Pennsylvania on Tuesday, according to the state Department of Environmental Protection.
DEP has issued a Code Orange Action Day in Philadelphia, Bucks, Chester, Delaware and Montgomery counties. It will remain effective throughout the day.
Young children, elderly adults and people with respiratory problems, including asthma, emphysema and bronchitis, are particularly vulnerable to elevated ozone levels and advised by the DEP to limit outdoor activity.
Code Orange is the second highest level on the DEP's ozone scale.
The combination of partly sunny skies, very light winds and temperatures in the low 90s will create "very favorable conditions" for ozone formation, according to the DEP. Though scattered thunderstorms are possible late in the afternoon, they are unlikely to keep ozone levels out of the Code Orange range.
Ozone concentrations are expected to drop by Wednesday as a cold front moves in.
The DEP advises residents and businesses to voluntarily restrict pollution-producing activities by refueling vehicles after dusk, setting air conditioner thermostats to high temperatures and carpooling or using public transit.
Ground level ozone is created by chemical reactions between oxides of nitrogen and volatile organic compounds when in the presence of sunlight, according to the U.S. Environmental Protection Agency. Major sources include emissions from industrial facilities and electric utilities, motor vehicle exhaust, gasoline vapors and chemical solvents.