An air quality alert has been issued for the greater Chicago area through Thursday night by the Illinois Environmental Protection Agency and could be extended for several days as the region preps for a hot July Fourth holiday weekend.
Poor air quality is expected to continue throughout the weekend, said Illinois EPA spokesperson Kim Biggs. Active adults and children, particularly those with respiratory or pulmonary diseases such as asthma, should avoid extended outdoor activity.
The alert was issued because of elevated ozone levels deemed unhealthy for sensitive groups, Biggs said. This type of ozone develops when vehicle and industry emissions react with sunlight, Biggs said.
“We see the highest level of ozone in the summer months, because you do need the heat and the sunlight to cause that reaction,” Biggs said.
This weekend’s air pollution issue is unrelated to the Sahara dust cloud, which Biggs said would instead bring elevated particulate matter. The Illinois EPA has not seen any changes in the air quality forecast related to the dust cloud, Biggs said.
On top of higher levels of air pollution, Chicagoans can expect temperatures in the high 80′s and low 90′s over the Fourth of July weekend, according to the National Weather Service. The weather’s expected to remain clear.
The forecast high temperatures are not atypical for this time of year, said Kevin Birk, a meteorologist with the National Weather Service’s Chicago-area office. Normal average high temperatures are in the mid-80s the first week of July, according to the weather service.
Birk advised locals to try to stay out of the sun as much as possible and drink plenty of fluids.
“We are going to have a string here of several days where we’re getting into the 90′s, so the progressive nature of this warm weather could weigh on some people,” Birk said. “The good news is we’re not expecting oppressive heat and humidity.”
Daytime highs away from Lake Michigan are likely to be in the low 90′s, while temperatures the lakefront will be around the 80′s because of onshore winds, Birk said.
Though some may be tempted to flock to Lake Michigan in search of cooler temperatures, Birk cautioned against crowding the lakefront and recommended Chicagoans keep social distancing in mind.
Chicago’s beaches aren’t yet open for swimming, because of the coronavirus pandemic.