A warning for anyone with lung diseases such as asthma, emphysema and bronchitis: Tuesday's air quality in the Philadelphia area could be unhealthy for you.
State environmental regulators have declared a "Code Orange" Air Quality Action day for high concentrations of ozone air pollution.
That means young children, the elderly and those with respiratory problems should limit outdoor activities.
"Tuesday will feature a day of intense heat and poor air quality," NBC10 First Alert Meteorologist Steve Sosna said.
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"High temperatures will reach near record highs in the middle to upper 90s," he said. "While humidity levels won't be outrageous, they'll be high enough to make the day uncomfortable."
Be sure to stay inside a safe place in air conditioning and open windows and use fans if you don't have A/C in your home. If you're using a fan, the EPA warns that windows or a door should be open to the outside; otherwise, you're just recirculating hot air, which is more dangerous.
Stay hydrated, too. During a heat health emergency, the Centers for Disease Control and Prevention recommends you drink water even when you're not thirsty.
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You should watch for signs of heat-related illness, which include headaches, nausea, dizziness, fatigue and excessive sweating.
The ozone warning covers Bucks, Chester, Delaware, Montgomery and Philadelphia counties.
"Code Orange" is the state's second-highest warning level for air pollution.
The Pennsylvania Department of Environmental Protection follows the federal Environmental Protection Agency's color codes, in which green means good air quality, yellow means moderate air quality, orange means unhealthy pollution levels for sensitive groups of people.
A Code Red indicates unhealthy pollution levels for everyone.
Take a look at a list of spraygrounds and cooling centers in Philadelphia.