An air quality advisory is in effect Friday for Westchester and Hudson Valley, which means people should limit the amount of time spent outdoors.

The NYS Department of Environmental Conservation says there is a heightened level of fine particles in the air. Even though the elderly, the young and people with respiratory problems are most at risk, doctors say the air quality affects everyone.

Dr. Robert Dematteo is a pulmonary specialist in Yonkers. He advises people to limit outdoor activity to the early morning and evening hours when the sun isn't so strong. Dematteo says the bad air quality can acerbate asthma, give people shortness of breath and stress the body.