The New York State Department of Environmental Conservation has issued an Air Quality Alert for the Southern Tier and Central New York for 11 a.m. through 11 p.m. May 21.

Matt Cardy/Getty Images

The alert is for Broome, Chenango, Cortland, Delaware, Tioga, Tompkins Counties and north through Syracuse.

The D.E.C. says air quality levels in outdoor air are predicted to be greater than the index value of 100 for ozone.

The Air Quality Index, or A.Q.I., was created as a way to correlate levels of different pollutants onto one scale so it’s easier to assess the health concern.  The higher the value, the greater the health concern.

Get our free mobile app

The New York State Department of Health recommends people think about limiting strenuous outdoor physical activity when pollution levels are elevated.

The very young and those with pre-existing respiratory problems like asthma or heart disease can be especially sensitive.

Seven Ways to Fight Off Ticks Using Rosemary