SmogRank / Episodes / United States
Illinois and Wisconsin, United States, June 2023
For 2 days, from 22 to 23 June 2023, 18 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Green Bay, Wisconsin, United States: 51.1 µg/m³ on 23 June, about 7.1× its usual 7.2.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 18 in 1 country
Days 2 22 to 23 June 2023
Worst day 23 June 18 cities counted
Furthest above usual 7.5× Green Bay
Day by day
Play 23 June 18 cities at twice their usual or more
Franklin Park Oak Lawn Chicago Gary Portage Moline Davenport Muscatine South Bend Holland La Crosse Iowa City Lafayette Elkhart Jenison Grand Rapids Kalamazoo Kokomo Waterloo Eau Claire Anderson Rochester Lansing Ankeny Des Moines Saint Paul Apple Valley Burnsville Lima Bay City Flint Ypsilanti Shakopee Toledo Hammond Calumet City Northbrook Naperville Des Plaines Cary Joliet Clinton East Chicago Milwaukee Zion South Milwaukee Bloomington Rockford Waukesha Madison Green Bay Appleton 19 Jun 20 21 22 23 24 25 26 Every measured city in the area, coloured by its PM2.5 that day; a dark ring marks a city at twice its usual or more. Bars: cities counted each day, coloured by their median level. Choose a day or press play; without JavaScript, the days link to that day's world ranking.
How it spread
Waukesha Waukesha, 19 June: 29.2 µg/m³, 3.7× usual Waukesha, 20 June: 22.1 µg/m³, 2.8× usual Waukesha, 21 June: 20.8 µg/m³, 2.7× usual Waukesha, 22 June: 26.2 µg/m³, 3.4× usual Waukesha, 23 June: 41.7 µg/m³, 5.3× usual Waukesha, 24 June: 20.3 µg/m³, 2.6× usual Waukesha, 25 June: 9.9 µg/m³, 1.3× usual Waukesha, 26 June: 42.6 µg/m³, 5.5× usual Milwaukee Milwaukee, 19 June: 28.7 µg/m³, 3.4× usual Milwaukee, 20 June: 23.4 µg/m³, 2.8× usual Milwaukee, 21 June: 21.0 µg/m³, 2.5× usual Milwaukee, 22 June: 26.9 µg/m³, 3.2× usual Milwaukee, 23 June: 36.0 µg/m³, 4.3× usual Milwaukee, 24 June: 14.5 µg/m³, 1.7× usual Milwaukee, 25 June: 10.9 µg/m³, 1.3× usual Milwaukee, 26 June: 44.6 µg/m³, 5.3× usual Appleton Appleton, 19 June: 28.2 µg/m³, 4.1× usual Appleton, 20 June: 23.1 µg/m³, 3.4× usual Appleton, 21 June: 19.4 µg/m³, 2.9× usual Appleton, 22 June: 27.7 µg/m³, 4.1× usual Appleton, 23 June: 50.8 µg/m³, 7.5× usual Appleton, 24 June: 35.7 µg/m³, 5.3× usual Appleton, 25 June: 10.5 µg/m³, 1.5× usual Appleton, 26 June: 67.7 µg/m³, 10.0× usual South Milwaukee South Milwaukee, 19 June: 28.1 µg/m³, 4.0× usual South Milwaukee, 20 June: 25.2 µg/m³, 3.5× usual South Milwaukee, 21 June: 21.5 µg/m³, 3.0× usual South Milwaukee, 22 June: 28.1 µg/m³, 4.0× usual South Milwaukee, 23 June: 33.3 µg/m³, 4.7× usual South Milwaukee, 24 June: 15.4 µg/m³, 2.2× usual South Milwaukee, 25 June: 13.4 µg/m³, 1.9× usual South Milwaukee, 26 June: 47.1 µg/m³, 6.6× usual Joliet Joliet, 19 June: 27.9 µg/m³, 3.1× usual Joliet, 20 June: 23.0 µg/m³, 2.5× usual Joliet, 21 June: 22.5 µg/m³, 2.5× usual Joliet, 22 June: 22.9 µg/m³, 2.5× usual Joliet, 23 June: 32.8 µg/m³, 3.6× usual Joliet, 24 June: 23.5 µg/m³, 2.6× usual Joliet, 25 June: 10.4 µg/m³, 1.1× usual Joliet, 26 June: 32.7 µg/m³, 3.6× usual Naperville Naperville, 19 June: 27.2 µg/m³, 2.9× usual Naperville, 20 June: 21.9 µg/m³, 2.3× usual Naperville, 21 June: 23.1 µg/m³, 2.5× usual Naperville, 22 June: 22.9 µg/m³, 2.4× usual Naperville, 23 June: 31.6 µg/m³, 3.4× usual Naperville, 24 June: 22.9 µg/m³, 2.4× usual Naperville, 25 June: 11.0 µg/m³, 1.2× usual Naperville, 26 June: 35.2 µg/m³, 3.7× usual Madison Madison, 19 June: 26.9 µg/m³, 3.9× usual Madison, 20 June: 22.0 µg/m³, 3.2× usual Madison, 21 June: 19.3 µg/m³, 2.8× usual Madison, 22 June: 21.1 µg/m³, 3.1× usual Madison, 23 June: 39.5 µg/m³, 5.7× usual Madison, 24 June: 27.2 µg/m³, 3.9× usual Madison, 25 June: 8.6 µg/m³, 1.2× usual Madison, 26 June: 38.0 µg/m³, 5.5× usual Calumet City Calumet City, 19 June: 25.6 µg/m³, 3.0× usual Calumet City, 20 June: 21.6 µg/m³, 2.5× usual Calumet City, 21 June: 22.9 µg/m³, 2.7× usual Calumet City, 22 June: 22.5 µg/m³, 2.6× usual Calumet City, 23 June: 25.8 µg/m³, 3.0× usual Calumet City, 24 June: 18.7 µg/m³, 2.2× usual Calumet City, 25 June: 10.8 µg/m³, 1.3× usual Calumet City, 26 June: 32.6 µg/m³, 3.8× usual Hammond Hammond, 19 June: 25.5 µg/m³, 2.9× usual Hammond, 20 June: 23.9 µg/m³, 2.7× usual Hammond, 21 June: 23.7 µg/m³, 2.7× usual Hammond, 22 June: 24.6 µg/m³, 2.8× usual Hammond, 23 June: 26.8 µg/m³, 3.0× usual Hammond, 24 June: 17.7 µg/m³, 2.0× usual Hammond, 25 June: 10.4 µg/m³, 1.2× usual Hammond, 26 June: 31.6 µg/m³, 3.6× usual Bloomington Bloomington, 19 June: 25.2 µg/m³, 3.2× usual Bloomington, 20 June: 22.3 µg/m³, 2.8× usual Bloomington, 21 June: 17.1 µg/m³, 2.2× usual Bloomington, 22 June: 20.9 µg/m³, 2.6× usual Bloomington, 23 June: 39.0 µg/m³, 4.9× usual Bloomington, 24 June: 24.5 µg/m³, 3.1× usual Bloomington, 25 June: 10.1 µg/m³, 1.3× usual Bloomington, 26 June: 19.8 µg/m³, 2.5× usual Green Bay Green Bay, 19 June: 21.2 µg/m³, 2.9× usual Green Bay, 20 June: 19.9 µg/m³, 2.8× usual Green Bay, 21 June: 17.3 µg/m³, 2.4× usual Green Bay, 22 June: 27.7 µg/m³, 3.8× usual Green Bay, 23 June: 51.1 µg/m³, 7.1× usual Green Bay, 24 June: 32.0 µg/m³, 4.4× usual Green Bay, 25 June: 12.4 µg/m³, 1.7× usual Green Bay, 26 June: 72.5 µg/m³, 10× usual Rockford Rockford, 19 June: 24.9 µg/m³, 3.1× usual Rockford, 20 June: 20.2 µg/m³, 2.5× usual Rockford, 21 June: 19.0 µg/m³, 2.4× usual Rockford, 22 June: 20.6 µg/m³, 2.6× usual Rockford, 23 June: 40.4 µg/m³, 5.1× usual Rockford, 24 June: 23.4 µg/m³, 2.9× usual Rockford, 25 June: 8.5 µg/m³, 1.1× usual Rockford, 26 June: 32.8 µg/m³, 4.1× usual East Chicago East Chicago, 19 June: 22.1 µg/m³, 2.9× usual East Chicago, 20 June: 22.9 µg/m³, 3.1× usual East Chicago, 21 June: 20.7 µg/m³, 2.8× usual East Chicago, 22 June: 22.1 µg/m³, 2.9× usual East Chicago, 23 June: 28.7 µg/m³, 3.8× usual East Chicago, 24 June: 12.0 µg/m³, 1.6× usual East Chicago, 25 June: 10.8 µg/m³, 1.4× usual East Chicago, 26 June: 30.8 µg/m³, 4.1× usual Zion Zion, 19 June: 20.1 µg/m³, 3.1× usual Zion, 20 June: 20.1 µg/m³, 3.1× usual Zion, 21 June: 15.6 µg/m³, 2.4× usual Zion, 22 June: 20.8 µg/m³, 3.3× usual Zion, 23 June: 28.5 µg/m³, 4.5× usual Zion, 24 June: 10.8 µg/m³, 1.7× usual Zion, 25 June: 8.1 µg/m³, 1.3× usual Zion, 26 June: 31.0 µg/m³, 4.8× usual Des Plaines Des Plaines, 19 June: 24.5 µg/m³, 2.9× usual Des Plaines, 20 June: 21.2 µg/m³, 2.5× usual Des Plaines, 21 June: 20.1 µg/m³, 2.4× usual Des Plaines, 22 June: 22.1 µg/m³, 2.6× usual Des Plaines, 23 June: 28.3 µg/m³, 3.4× usual Des Plaines, 24 June: 14.6 µg/m³, 1.7× usual Des Plaines, 25 June: 10.6 µg/m³, 1.3× usual Des Plaines, 26 June: 33.1 µg/m³, 3.9× usual Northbrook Northbrook, 19 June: 22.6 µg/m³, 2.7× usual Northbrook, 20 June: 21.0 µg/m³, 2.5× usual Northbrook, 21 June: 19.4 µg/m³, 2.3× usual Northbrook, 22 June: 20.2 µg/m³, 2.4× usual Northbrook, 23 June: 28.3 µg/m³, 3.4× usual Northbrook, 24 June: 11.0 µg/m³, 1.3× usual Northbrook, 25 June: 11.6 µg/m³, 1.4× usual Northbrook, 26 June: 34.0 µg/m³, 4.0× usual Cary Cary, 19 June: 23.5 µg/m³, 2.8× usual Cary, 20 June: 20.7 µg/m³, 2.5× usual Cary, 21 June: 19.9 µg/m³, 2.4× usual Cary, 22 June: 21.1 µg/m³, 2.5× usual Cary, 23 June: 28.2 µg/m³, 3.4× usual Cary, 24 June: 17.3 µg/m³, 2.1× usual Cary, 25 June: 9.3 µg/m³, 1.1× usual Cary, 26 June: 32.6 µg/m³, 3.9× usual Clinton Clinton, 19 June: 23.7 µg/m³, 3.1× usual Clinton, 20 June: 19.4 µg/m³, 2.5× usual Clinton, 21 June: 18.7 µg/m³, 2.4× usual Clinton, 22 June: 19.0 µg/m³, 2.5× usual Clinton, 23 June: 27.4 µg/m³, 3.6× usual Clinton, 24 June: 23.4 µg/m³, 3.0× usual Clinton, 25 June: 6.9 µg/m³, 0.9× usual Clinton, 26 June: 22.3 µg/m³, 2.9× usual 19 Jun 20 21 22 23 24 25 26 Every counted city, in the order the episode reached them, 3 days before to 3 after. Each square is a day, coloured by that day's PM2.5; outlined: at twice the city's usual or more. Good 0–50
Moderate 51–100
Sensitive groups 101–150
Unhealthy 151–200
Very unhealthy 201–300
Hazardous 301+
Every city it reached
City Days Highest Usual Above usual
Green Bay Wisconsin, United States 2 26 June 7.2 10× Appleton Wisconsin, United States 2 26 June 6.8 10.0× South Milwaukee Wisconsin, United States 2 26 June 7.1 6.6× Madison Wisconsin, United States 1 23 June 6.9 5.7× Waukesha Wisconsin, United States 2 26 June 7.8 5.5× Milwaukee Wisconsin, United States 2 26 June 8.4 5.3× Rockford Illinois, United States 1 23 June 8.0 5.1× Bloomington Illinois, United States 1 23 June 7.9 4.9× Zion Illinois, United States 1 26 June 6.4 4.8× East Chicago Indiana, United States 1 26 June 7.5 4.1× Northbrook Illinois, United States 1 26 June 8.4 4.0× Des Plaines Illinois, United States 1 26 June 8.4 3.9× Cary Illinois, United States 1 26 June 8.4 3.9× Calumet City Illinois, United States 1 26 June 8.6 3.8× Naperville Illinois, United States 1 26 June 9.4 3.7× Joliet Illinois, United States 1 23 June 9.1 3.6× Clinton Iowa, United States 1 23 June 7.7 3.6× Hammond Indiana, United States 1 26 June 8.9 3.6×
Daily means in µg/m³. Usual: the city's median for this time of year (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that.
Against other episodes in the United States
Number 20 of 41 episodes in the United States since our records began, by cities reached.
North-eastern United States and Canada, June and July 2023 279 North-eastern United States and Canada, May and June 2023 260 North-eastern United States and Canada, July 2023 241 North-eastern United States and Canada, June 2023 161 North-western United States and Canada, August 2023 110 North-eastern United States and Canada, July 2023 75 Western United States, September 2023 61 South-eastern United States, October 2023 47 North-eastern United States, July 2023 46 North-western United States and Canada, May 2023 42 Western United States, December 2023 32 Northern United States, January 2023 32 Illinois and Wisconsin, United States, June 2023 18 Bars: cities reached; colour: the level of the episode's highest daily reading. All 41 .
Use this page SmogRank, Illinois and Wisconsin, United States, June 2023: 18 cities with PM2.5 at twice their usual or more, 22 to 23 June 2023, smogrank.com/episodes/2023-06-illinois-and-wisconsin-united-states (accessed 2 October 2026).
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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms .
An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes . Values are each city's daily mean of its own monitors; causes are the usual kinds for a pattern like this, not a confirmed source.
