SmogRank / Episodes / United States
North-eastern United States, July 2025
For 2 days, from 21 to 22 July 2025, 32 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Des Plaines, Illinois, United States: 39.6 µg/m³ on 21 July, about 4.0× its usual 10.0.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 32 in 1 country
Days 2 21 to 22 July 2025
Worst day 21 July 26 cities counted
Furthest above usual 4.0× Blaine
Day by day
Play 21 July 26 cities at twice their usual or more
Calumet City Hammond East Chicago Gary Portage Waukesha Oconomowoc Michigan City Bloomington Champaign South Bend Peoria Lafayette Clinton Elkhart Decatur Appleton Moline Kokomo Davenport Green Bay Terre Haute Springfield Fishers Muscatine Anderson Fort Wayne Bloomington Muncie Iowa City Cedar Rapids Columbus Upper Alton Lansing Jasper Granite City East Saint Louis St. Louis University City Lemay Arnold Lima Waterloo New Albany Jeffersonville Louisville Ann Arbor Saint Matthews White Oak Dayton Ypsilanti Bay City Toledo Cincinnati Norwood Mason Lebanon Fort Thomas Springfield Redford Taylor Southfield Lincoln Park Dearborn Detroit Windsor Columbia Eastpointe Dublin Ankeny Des Moines Columbus Westerville Gahanna Port Huron Apple Valley Sarnia Burnsville Chatham Shakopee Mankato Saint Michael Ashland Huntington Dolton Wyoming Middletown Bridgeview Rochester Naperville Aurora Oak Lawn Joliet Portsmouth Indianapolis Minneapolis Milwaukee Saint Paul Elgin Kalamazoo Jenison Chicago Brookfield Blaine Holland Grand Rapids Elmwood Park South Milwaukee Northbrook Franklin Park Cary Madison Rockford Eau Claire Zion Des Plaines 18 Jul 19 20 21 22 23 24 25 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
Des Plaines Des Plaines, 18 July: 5.9 µg/m³, 0.6× usual Des Plaines, 19 July: 8.1 µg/m³, 0.8× usual Des Plaines, 20 July: 9.3 µg/m³, 0.9× usual Des Plaines, 21 July: 39.6 µg/m³, 4.0× usual Des Plaines, 22 July: 25.0 µg/m³, 2.5× usual Des Plaines, 23 July: 18.9 µg/m³, 1.9× usual Des Plaines, 24 July: 11.6 µg/m³, 1.2× usual Des Plaines, 25 July: 7.7 µg/m³, 0.8× usual Rockford Rockford, 18 July: 3.9 µg/m³, 0.4× usual Rockford, 19 July: 4.4 µg/m³, 0.4× usual Rockford, 20 July: 6.4 µg/m³, 0.6× usual Rockford, 21 July: 38.9 µg/m³, 3.7× usual Rockford, 22 July: 22.3 µg/m³, 2.1× usual Rockford, 23 July: 18.1 µg/m³, 1.7× usual Rockford, 24 July: 7.0 µg/m³, 0.7× usual Rockford, 25 July: 4.5 µg/m³, 0.4× usual Franklin Park Franklin Park, 18 July: 7.6 µg/m³, 0.6× usual Franklin Park, 19 July: 7.5 µg/m³, 0.6× usual Franklin Park, 20 July: 8.8 µg/m³, 0.7× usual Franklin Park, 21 July: 38.6 µg/m³, 3.3× usual Franklin Park, 22 July: 29.0 µg/m³, 2.5× usual Franklin Park, 23 July: 20.0 µg/m³, 1.7× usual Franklin Park, 24 July: 12.6 µg/m³, 1.1× usual Franklin Park, 25 July: 6.7 µg/m³, 0.6× usual Elmwood Park Elmwood Park, 18 July: 6.0 µg/m³, 0.5× usual Elmwood Park, 19 July: 7.4 µg/m³, 0.6× usual Elmwood Park, 20 July: 8.4 µg/m³, 0.7× usual Elmwood Park, 21 July: 35.2 µg/m³, 3.0× usual Elmwood Park, 22 July: 26.8 µg/m³, 2.3× usual Elmwood Park, 23 July: 18.8 µg/m³, 1.6× usual Elmwood Park, 24 July: 10.7 µg/m³, 0.9× usual Elmwood Park, 25 July: 5.8 µg/m³, 0.5× usual Elgin Elgin, 18 July: 4.5 µg/m³, 0.3× usual Elgin, 19 July: 5.2 µg/m³, 0.4× usual Elgin, 20 July: 6.1 µg/m³, 0.5× usual Elgin, 21 July: 35.0 µg/m³, 2.7× usual Elgin, 22 July: 24.2 µg/m³, 1.8× usual Elgin, 23 July: 17.2 µg/m³, 1.3× usual Elgin, 24 July: 9.5 µg/m³, 0.7× usual Elgin, 25 July: 4.5 µg/m³, 0.3× usual Cary Cary, 18 July: 4.4 µg/m³, 0.5× usual Cary, 19 July: 6.0 µg/m³, 0.6× usual Cary, 20 July: 7.0 µg/m³, 0.7× usual Cary, 21 July: 34.9 µg/m³, 3.6× usual Cary, 22 July: 21.3 µg/m³, 2.2× usual Cary, 23 July: 17.1 µg/m³, 1.8× usual Cary, 24 July: 9.8 µg/m³, 1.0× usual Cary, 25 July: 4.8 µg/m³, 0.5× usual Eau Claire Eau Claire, 18 July: 3.6 µg/m³, 0.4× usual Eau Claire, 19 July: 5.0 µg/m³, 0.6× usual Eau Claire, 20 July: 12.6 µg/m³, 1.4× usual Eau Claire, 21 July: 33.4 µg/m³, 3.8× usual Eau Claire, 22 July: 12.3 µg/m³, 1.4× usual Eau Claire, 23 July: 6.9 µg/m³, 0.8× usual Eau Claire, 24 July: 5.2 µg/m³, 0.6× usual Eau Claire, 25 July: 44.4 µg/m³, 5.0× usual Kalamazoo Kalamazoo, 18 July: 4.1 µg/m³, 0.3× usual Kalamazoo, 19 July: 5.6 µg/m³, 0.5× usual Kalamazoo, 20 July: 5.5 µg/m³, 0.5× usual Kalamazoo, 21 July: 33.4 µg/m³, 2.8× usual Kalamazoo, 22 July: 14.4 µg/m³, 1.2× usual Kalamazoo, 23 July: 11.7 µg/m³, 1.0× usual Kalamazoo, 24 July: 11.3 µg/m³, 1.0× usual Kalamazoo, 25 July: 5.3 µg/m³, 0.4× usual Northbrook Northbrook, 18 July: 3.0 µg/m³, 0.3× usual Northbrook, 19 July: 5.1 µg/m³, 0.5× usual Northbrook, 20 July: 7.6 µg/m³, 0.7× usual Northbrook, 21 July: 32.1 µg/m³, 3.1× usual Northbrook, 22 July: 18.4 µg/m³, 1.8× usual Northbrook, 23 July: 12.0 µg/m³, 1.2× usual Northbrook, 24 July: 5.5 µg/m³, 0.5× usual Northbrook, 25 July: 6.7 µg/m³, 0.7× usual Madison Madison, 18 July: 4.0 µg/m³, 0.5× usual Madison, 19 July: 4.6 µg/m³, 0.5× usual Madison, 20 July: 8.8 µg/m³, 1.0× usual Madison, 21 July: 31.1 µg/m³, 3.7× usual Madison, 22 July: 15.7 µg/m³, 1.9× usual Madison, 23 July: 13.5 µg/m³, 1.6× usual Madison, 24 July: 3.8 µg/m³, 0.5× usual Madison, 25 July: 10.8 µg/m³, 1.3× usual Grand Rapids Grand Rapids, 18 July: 4.1 µg/m³, 0.4× usual Grand Rapids, 19 July: 6.3 µg/m³, 0.6× usual Grand Rapids, 20 July: 12.2 µg/m³, 1.2× usual Grand Rapids, 21 July: 30.8 µg/m³, 3.0× usual Grand Rapids, 22 July: 10.9 µg/m³, 1.0× usual Grand Rapids, 23 July: 12.6 µg/m³, 1.2× usual Grand Rapids, 24 July: 11.3 µg/m³, 1.1× usual Grand Rapids, 25 July: 6.6 µg/m³, 0.6× usual Zion Zion, 18 July: 3.4 µg/m³, 0.4× usual Zion, 19 July: 6.3 µg/m³, 0.8× usual Zion, 20 July: 9.2 µg/m³, 1.2× usual Zion, 21 July: 30.6 µg/m³, 3.9× usual Zion, 22 July: 16.1 µg/m³, 2.1× usual Zion, 23 July: 14.1 µg/m³, 1.8× usual Zion, 24 July: 8.0 µg/m³, 1.0× usual Zion, 25 July: 10.5 µg/m³, 1.3× usual Jenison Jenison, 18 July: 4.3 µg/m³, 0.4× usual Jenison, 19 July: 5.9 µg/m³, 0.6× usual Jenison, 20 July: 8.1 µg/m³, 0.8× usual Jenison, 21 July: 30.0 µg/m³, 2.9× usual Jenison, 22 July: 10.5 µg/m³, 1.0× usual Jenison, 23 July: 11.9 µg/m³, 1.2× usual Jenison, 24 July: 10.0 µg/m³, 1.0× usual Jenison, 25 July: 5.3 µg/m³, 0.5× usual Bridgeview Bridgeview, 18 July: 9.0 µg/m³, 0.7× usual Bridgeview, 19 July: 6.0 µg/m³, 0.4× usual Bridgeview, 20 July: 8.2 µg/m³, 0.6× usual Bridgeview, 21 July: 30.0 µg/m³, 2.2× usual Bridgeview, 22 July: 28.2 µg/m³, 2.1× usual Bridgeview, 23 July: 17.9 µg/m³, 1.3× usual Bridgeview, 24 July: 11.0 µg/m³, 0.8× usual Bridgeview, 25 July: 8.4 µg/m³, 0.6× usual Holland Holland, 18 July: 5.8 µg/m³, 0.6× usual Holland, 19 July: 7.9 µg/m³, 0.8× usual Holland, 20 July: 8.6 µg/m³, 0.9× usual Holland, 21 July: 29.8 µg/m³, 3.0× usual Holland, 22 July: 14.5 µg/m³, 1.4× usual Holland, 23 July: 14.3 µg/m³, 1.4× usual Holland, 24 July: 14.6 µg/m³, 1.4× usual Holland, 25 July: 8.3 µg/m³, 0.8× usual Chicago Chicago, 18 July: 6.4 µg/m³, 0.6× usual Chicago, 19 July: 6.4 µg/m³, 0.6× usual Chicago, 20 July: 8.1 µg/m³, 0.8× usual Chicago, 21 July: 29.4 µg/m³, 2.9× usual Chicago, 22 July: 27.4 µg/m³, 2.7× usual Chicago, 23 July: 17.6 µg/m³, 1.7× usual Chicago, 24 July: 10.6 µg/m³, 1.0× usual Chicago, 25 July: 6.3 µg/m³, 0.6× usual Brookfield Brookfield, 18 July: 7.1 µg/m³, 0.7× usual Brookfield, 19 July: 5.3 µg/m³, 0.5× usual Brookfield, 20 July: 6.4 µg/m³, 0.6× usual Brookfield, 21 July: 28.7 µg/m³, 2.9× usual Brookfield, 22 July: 28.1 µg/m³, 2.8× usual Brookfield, 23 July: 16.8 µg/m³, 1.7× usual Brookfield, 24 July: 10.8 µg/m³, 1.1× usual Brookfield, 25 July: 6.5 µg/m³, 0.7× usual Naperville Naperville, 18 July: 3.8 µg/m³, 0.3× usual Naperville, 19 July: 5.6 µg/m³, 0.5× usual Naperville, 20 July: 6.4 µg/m³, 0.6× usual Naperville, 21 July: 27.9 µg/m³, 2.4× usual Naperville, 22 July: 26.7 µg/m³, 2.3× usual Naperville, 23 July: 17.3 µg/m³, 1.5× usual Naperville, 24 July: 8.9 µg/m³, 0.8× usual Naperville, 25 July: 6.5 µg/m³, 0.6× usual Wyoming Wyoming, 18 July: 7.6 µg/m³, 0.6× usual Wyoming, 19 July: 9.3 µg/m³, 0.7× usual Wyoming, 20 July: 11.7 µg/m³, 0.9× usual Wyoming, 21 July: 27.5 µg/m³, 2.1× usual Wyoming, 22 July: 12.5 µg/m³, 1.0× usual Wyoming, 23 July: 14.8 µg/m³, 1.1× usual Wyoming, 24 July: 16.1 µg/m³, 1.2× usual Wyoming, 25 July: 10.2 µg/m³, 0.8× usual Milwaukee Milwaukee, 18 July: 4.9 µg/m³, 0.5× usual Milwaukee, 19 July: 7.1 µg/m³, 0.7× usual Milwaukee, 20 July: 15.5 µg/m³, 1.5× usual Milwaukee, 21 July: 26.9 µg/m³, 2.6× usual Milwaukee, 22 July: 20.2 µg/m³, 2.0× usual Milwaukee, 23 July: 16.2 µg/m³, 1.6× usual Milwaukee, 24 July: 6.9 µg/m³, 0.7× usual Milwaukee, 25 July: 20.7 µg/m³, 2.0× usual South Milwaukee South Milwaukee, 18 July: 4.1 µg/m³, 0.5× usual South Milwaukee, 19 July: 5.6 µg/m³, 0.7× usual South Milwaukee, 20 July: 10.4 µg/m³, 1.2× usual South Milwaukee, 21 July: 26.5 µg/m³, 3.1× usual South Milwaukee, 22 July: 18.1 µg/m³, 2.1× usual South Milwaukee, 23 July: 14.9 µg/m³, 1.8× usual South Milwaukee, 24 July: 6.6 µg/m³, 0.8× usual South Milwaukee, 25 July: 17.6 µg/m³, 2.1× usual Saint Paul Saint Paul, 18 July: 4.3 µg/m³, 0.4× usual Saint Paul, 19 July: 6.3 µg/m³, 0.6× usual Saint Paul, 20 July: 7.8 µg/m³, 0.8× usual Saint Paul, 21 July: 26.2 µg/m³, 2.6× usual Saint Paul, 22 July: 11.2 µg/m³, 1.1× usual Saint Paul, 23 July: 6.6 µg/m³, 0.7× usual Saint Paul, 24 July: 13.8 µg/m³, 1.4× usual Saint Paul, 25 July: 47.7 µg/m³, 4.7× usual Minneapolis Minneapolis, 18 July: 6.0 µg/m³, 0.6× usual Minneapolis, 19 July: 7.0 µg/m³, 0.7× usual Minneapolis, 20 July: 8.1 µg/m³, 0.8× usual Minneapolis, 21 July: 25.6 µg/m³, 2.5× usual Minneapolis, 22 July: 13.1 µg/m³, 1.3× usual Minneapolis, 23 July: 7.4 µg/m³, 0.7× usual Minneapolis, 24 July: 15.8 µg/m³, 1.6× usual Minneapolis, 25 July: 49.3 µg/m³, 4.9× usual Blaine Blaine, 18 July: 4.7 µg/m³, 0.6× usual Blaine, 19 July: 5.3 µg/m³, 0.6× usual Blaine, 20 July: 9.4 µg/m³, 1.1× usual Blaine, 21 July: 25.5 µg/m³, 3.0× usual Blaine, 22 July: 10.4 µg/m³, 1.2× usual Blaine, 23 July: 6.1 µg/m³, 0.7× usual Blaine, 24 July: 16.6 µg/m³, 2.0× usual Blaine, 25 July: 47.3 µg/m³, 5.6× usual Aurora Aurora, 18 July: 3.9 µg/m³, 0.4× usual Aurora, 19 July: 5.0 µg/m³, 0.5× usual Aurora, 20 July: 5.0 µg/m³, 0.5× usual Aurora, 21 July: 25.3 µg/m³, 2.3× usual Aurora, 22 July: 26.2 µg/m³, 2.4× usual Aurora, 23 July: 16.2 µg/m³, 1.5× usual Aurora, 24 July: 8.4 µg/m³, 0.8× usual Aurora, 25 July: 5.4 µg/m³, 0.5× usual Rochester Rochester, 18 July: 6.4 µg/m³, 0.6× usual Rochester, 19 July: 7.1 µg/m³, 0.7× usual Rochester, 20 July: 6.3 µg/m³, 0.6× usual Rochester, 21 July: 25.0 µg/m³, 2.4× usual Rochester, 22 July: 9.9 µg/m³, 0.9× usual Rochester, 23 July: 7.0 µg/m³, 0.7× usual Rochester, 24 July: 3.8 µg/m³, 0.4× usual Rochester, 25 July: 14.1 µg/m³, 1.3× usual Indianapolis Indianapolis, 18 July: 5.5 µg/m³, 0.5× usual Indianapolis, 19 July: 6.7 µg/m³, 0.6× usual Indianapolis, 20 July: 6.5 µg/m³, 0.6× usual Indianapolis, 21 July: 9.7 µg/m³, 0.9× usual Indianapolis, 22 July: 27.9 µg/m³, 2.5× usual Indianapolis, 23 July: 17.6 µg/m³, 1.6× usual Indianapolis, 24 July: 14.7 µg/m³, 1.3× usual Indianapolis, 25 July: 12.1 µg/m³, 1.1× usual Joliet Joliet, 18 July: 4.8 µg/m³, 0.4× usual Joliet, 19 July: 5.2 µg/m³, 0.5× usual Joliet, 20 July: 5.5 µg/m³, 0.5× usual Joliet, 21 July: 20.5 µg/m³, 1.9× usual Joliet, 22 July: 27.5 µg/m³, 2.5× usual Joliet, 23 July: 17.2 µg/m³, 1.6× usual Joliet, 24 July: 9.5 µg/m³, 0.9× usual Joliet, 25 July: 5.1 µg/m³, 0.5× usual Dolton Dolton, 18 July: 7.9 µg/m³, 0.6× usual Dolton, 19 July: 7.0 µg/m³, 0.5× usual Dolton, 20 July: 6.6 µg/m³, 0.5× usual Dolton, 21 July: 22.1 µg/m³, 1.7× usual Dolton, 22 July: 26.9 µg/m³, 2.1× usual Dolton, 23 July: 17.5 µg/m³, 1.4× usual Dolton, 24 July: 12.0 µg/m³, 0.9× usual Dolton, 25 July: 6.2 µg/m³, 0.5× usual Middletown Middletown, 18 July: no reading Middletown, 19 July: no reading Middletown, 20 July: no reading Middletown, 21 July: 16.1 µg/m³, 1.4× usual Middletown, 22 July: 26.2 µg/m³, 2.2× usual Middletown, 23 July: no reading Middletown, 24 July: no reading Middletown, 25 July: no reading Oak Lawn Oak Lawn, 18 July: 6.1 µg/m³, 0.6× usual Oak Lawn, 19 July: 5.4 µg/m³, 0.5× usual Oak Lawn, 20 July: 6.4 µg/m³, 0.6× usual Oak Lawn, 21 July: 24.3 µg/m³, 2.4× usual Oak Lawn, 22 July: 25.7 µg/m³, 2.5× usual Oak Lawn, 23 July: 16.0 µg/m³, 1.6× usual Oak Lawn, 24 July: 9.4 µg/m³, 0.9× usual Oak Lawn, 25 July: 5.3 µg/m³, 0.5× usual Portsmouth Portsmouth, 18 July: 6.9 µg/m³, 0.7× usual Portsmouth, 19 July: 7.1 µg/m³, 0.7× usual Portsmouth, 20 July: 7.4 µg/m³, 0.7× usual Portsmouth, 21 July: 10.9 µg/m³, 1.1× usual Portsmouth, 22 July: 25.0 µg/m³, 2.5× usual Portsmouth, 23 July: 18.0 µg/m³, 1.8× usual Portsmouth, 24 July: 15.1 µg/m³, 1.5× usual Portsmouth, 25 July: 14.5 µg/m³, 1.5× usual 18 Jul 19 20 21 22 23 24 25 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
Blaine Minnesota, United States 1 25 July 8.4 5.6× Eau Claire Wisconsin, United States 1 25 July 8.9 5.0× Minneapolis Minnesota, United States 1 25 July 10.1 4.9× Saint Paul Minnesota, United States 1 25 July 10.1 4.7× Des Plaines Illinois, United States 2 21 July 10.0 4.0× Zion Illinois, United States 1 21 July 7.8 3.9× Madison Wisconsin, United States 1 21 July 8.4 3.7× Rockford Illinois, United States 1 21 July 10.6 3.7× Cary Illinois, United States 1 21 July 9.6 3.6× Franklin Park Illinois, United States 2 21 July 11.8 3.3× Northbrook Illinois, United States 1 21 July 10.2 3.1× South Milwaukee Wisconsin, United States 1 21 July 8.5 3.1× Elmwood Park Illinois, United States 2 21 July 11.8 3.0× Grand Rapids Michigan, United States 1 21 July 10.4 3.0× Holland Michigan, United States 1 21 July 10.1 3.0× Jenison Michigan, United States 1 21 July 10.2 2.9× Chicago Illinois, United States 2 21 July 10.1 2.9× Brookfield Illinois, United States 2 21 July 9.9 2.9× Kalamazoo Michigan, United States 1 21 July 11.8 2.8× Elgin Illinois, United States 1 21 July 13.1 2.7× Milwaukee Wisconsin, United States 1 21 July 10.2 2.6× Portsmouth Ohio, United States 1 22 July 9.9 2.5× Joliet Illinois, United States 1 22 July 11.0 2.5× Oak Lawn Illinois, United States 1 22 July 10.3 2.5× Indianapolis Indiana, United States 1 22 July 11.2 2.5× Naperville Illinois, United States 2 21 July 11.5 2.4× Aurora Illinois, United States 2 22 July 10.8 2.4× Rochester Minnesota, United States 1 21 July 10.6 2.4× Bridgeview Illinois, United States 2 21 July 13.4 2.2× Middletown Ohio, United States 1 22 July 11.9 2.2× Wyoming Michigan, United States 1 21 July 13.1 2.1× Dolton Illinois, United States 1 22 July 12.9 2.1×
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 25 of 98 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, July 2026 264 North-eastern United States and Canada, May and June 2023 260 North-eastern United States and Canada, July and August 2025 241 North-eastern United States and Canada, July 2023 241 North-eastern United States and Canada, June 2025 196 North-eastern United States and Canada, June 2023 161 North-eastern United States and Canada, July 2025 119 North-western United States and Canada, August 2023 110 North-eastern United States, June 2025 104 North-western United States and Canada, August 2026 99 North-eastern United States and Canada, February 2026 96 North-eastern United States, July 2025 32 Bars: cities reached; colour: the level of the episode's highest daily reading. All 98 .
Use this page SmogRank, North-eastern United States, July 2025: 32 cities with PM2.5 at twice their usual or more, 21 to 22 July 2025, smogrank.com/episodes/2025-07-north-eastern-united-states-2 (accessed 3 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.
