(WHTM) — Canadian wildfire smoke is plaguing Pennsylvania once again.

The state’s Department of Environmental Protection declared a code orange air quality day for Tuesday, Aug. 5, for 20 counties. It comes as more than 200 PA communities head outside for National Night Out the same night.

On code orange days, young children, the elderly and those with respiratory problems are especially vulnerable to the effects of air pollution and should limit outdoor activities. Luckily, there are ways to keep safe when the air is not.

Two years ago, more than 3,000 Canadian wildfires blanketed the eastern Untied States with smoke. The National Weather Service issued a code red for central Pennsylvania that summer, meaning the air quality posed a danger to the general population.

The smoke lingered for weeks that summer, blanketing sites like the State Capitol in a haze.

Live tracking of air quality is available at www.airnow.gov.