RALEIGH, N.C. (AP) — State environmental officials are warning of the possibility of unhealthy air in six North Carolina counties.

Officials have issued a Code Orange advisory for air quality in Cabarrus, Gaston, Lincoln, Mecklenburg, Rowan, Union and southern Iredell counties for Thursday. A Code Orange advisory means people who are active and those with respiratory disease such as asthma, should avoid prolonged outdoor exertion. Everyone else, especially children, should limit prolonged outdoor exertion.

In addition, an outdoor burning ban is in effect.

The main pollutant will be ozone.

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