Denver Weather: Even Worse Air Quality Thursday; Unhealthy For Everyone!

DENVER (CBS4) - The Colorado Department of Public Health and Environment has taken the somewhat rare step of declaring the air in the Denver metro area unhealthy for everyone on Thursday.

This declaration means everyone, regardless of age or health, should "reduce prolonged or heavy exertion" outside. In other words, it's okay to be outside but strenuous activity like running or long distance cycling is strongly discouraged. Meanwhile people with heart or lung diseases, older adults, and young child should completely avoid outdoor activity on Thursday.

The primary reason for the very poor air quality is an inversion that continues to be setup over the metro area. An inversion means temperatures are colder along the ground compared to higher in the atmosphere which is opposite of normal. The warmer temperatures aloft create a lid that traps pollutants near the ground.