With an expected high of 92° Thursday, a code orange air quality alert has been issued for much of the area.
The Air Quality Index measures the amount of pollutants in the air from 0 to 500, designating one of six colors to the results. The higher the number, the more polluted the air is, AIRNow.gov explains.
In this case, code orange means the air may be unhealthy to sensitive groups. Those with respiratory/heart ailments, older adults and children should avoid prolonged or strenuous outdoor activity.
The color codes range from green to maroon.
Thursday marks day two of a five-day heatwave. The stagnant air produced by the high pressure system creates higher levels of air pollutants. But every hot day won't produce an air quality alert, Storm Team4 meteorologist Amelia Segal says.
However, this week's persistent weather pattern will likely yield an air quality alert for Friday.