Mobile phones across Chicago on Wednesday morning, April 23, warned their users of air quality akin to sitting at the foot of an erupting volcano or on the edge of a wildfire. It turned out to be much less serious than a blaze in Bronzeville.
Warnings showed air quality readings of more than 400, which is described as “hazardous” and possibly dangerous for some with sensitivities like asthma. For scale, Google showed Lacey Township, New Jersey, had an AQI topping out around 195 on Thursday afternoon, April 24, due to the Jones Road Fire burning there.
Maps posted online show Chicago in a circle of violet and magenta hues, surrounded by safer green shades across the rest of the nearby counties.
The alerts caused speculation on social media platforms about pollution, fires and even an Indiana plant explosion until readings fell back to safe levels later that day.
Was it really that bad?
No.
The Illinois Environmental Protection Agency’s Bureau of Air monitors air quality around the state. It submits its information to the U.S. Environmental Protection Agency, which showed no signs of hazardous air quality on Wednesday. IEPA spokeswoman Kim Biggs told Straight Arrow News that “the Chicago area has continued to show good or moderate air quality.”
What happened?
Biggs checked with her federal counterpart on Wednesday and found that the source of the dangerous air quality readings was caused by a glitch in a widely used monitoring service.
“The alerts were resulting from a commercial air pollution sensor application integrated into Apple and Android platforms that was showing a very large swath of Chicago as having unhealthy air quality,” she said Thursday. “The data and resulting health warning messaging based on this application were erroneous. We continue to have confidence in EPA’s AirNow website based on data from reliable sources.”
AirNow didn’t indicate any air quality issues Wednesday.
Google spokeswoman Abigail Jaffe confirmed the issue was a technical glitch from a third-party service.
“We showed elevated air quality in Chicago yesterday due to a third-party monitoring station inaccurately reporting high measurements — this information is now displaying correctly,” Jaffe told Straight Arrow News on Thursday.
Google compiles its air quality data from several sources, including government monitoring stations, fire smoke and dust models, weather patterns and even traffic data that would indicate more exhaust pollution. Like Apple, Google also uses third parties like PurpleAir and BreezoMeter.
The New York Times first reported on the glitch.
