Illinois 121, Decatur, Illinois, United States Historical Air Quality Analysis
Dive into detailed Air Quality Insights with historical data, monthly patterns, and yearly trends at your fingertips!
Good
050
Moderate
100
Poor
150
Unhealthy
200
Severe
300
Hazardous
301+
August Air Quality Analysis
Illinois 121, Decatur, Illinois, United States
2025
AQI
.
Days
AQI Trends: Highest and Lowest
Highest AQI recorded on
1st Aug 2025
112AQILowest AQI recorded on
4th Aug 2025
48AQISame Day Analysis (10th August ):
On this day, AQI across the 1 years varied significantly: 2025 ranks 1st highest AQI at 51 of Moderate air quality on the same day.
Download 2024 Annual Data
World Air Quality Report
Day & Night AQI Trend: 10th Aug - 11th Aug 2025
Illinois 121, Decatur, Illinois, United States
AQI
Day
Night
.
5 AM10th Aug 2025
8 PM
4 AM11th Aug 2025
Day time
Avg. Highest Time
7AM10th Aug
52AQI
Avg. Lowest Time
1PM10th Aug
46AQI
Night time
Avg. Highest Time
10PM10th Aug
52AQI
Avg. Lowest Time
4AM11th Aug
44AQI
In the last 24 hours,
Illinois 121's AQI reached its highest point of 52 at 7 AM during the Day, while the lowest point, 44, was recorded at 4 AM during the Night between 10th Aug and 11th Aug 2025.
Day & Night AQI Trend : Jul - Aug 2025
Illinois 121, Decatur, Illinois, United States
JulAug
12th - 13th13th - 14th14th - 15th15th - 16th16th - 17th17th - 18th18th - 19th19th - 20th20th - 21st21st - 22nd22nd - 23rd23rd - 24th24th - 25th25th - 26th26th - 27th27th - 28th28th - 29th29th - 30th30th - 31st31st - 01st01st - 02nd02nd - 03rd03rd - 04th04th - 05th05th - 06th06th - 07th07th - 08th08th - 09th09th - 10th10th - 11th11th
Day
Night
12th Jul 2025285 AMAQI
12th Jul 2025296 AMAQI
12th Jul 2025307 AMAQI
12th Jul 2025308 AMAQI
12th Jul 2025319 AMAQI
12th Jul 20253110 AMAQI
12th Jul 20253211 AMAQI
12th Jul 20253312 PMAQI
12th Jul 2025341 PMAQI
12th Jul 2025362 PMAQI
12th Jul 2025363 PMAQI
12th Jul 2025384 PMAQI
12th Jul 2025365 PMAQI
12th Jul 2025366 PMAQI
12th Jul 2025327 PMAQI
12th Jul 2025328 PMAQI
12th Jul 2025349 PMAQI
12th Jul 20253510 PMAQI
12th Jul 20253511 PMAQI
13th Jul 20253612 AMAQI
13th Jul 2025361 AMAQI
13th Jul 2025292 AMAQI
13th Jul 2025273 AMAQI
13th Jul 2025284 AMAQI
25°C21/29°C
13th Jul 2025305 AMAQI
13th Jul 2025326 AMAQI
13th Jul 2025357 AMAQI
13th Jul 2025428 AMAQI
13th Jul 2025529 AMAQI
13th Jul 20255610 AMAQI
13th Jul 20256111 AMAQI
13th Jul 20255712 PMAQI
13th Jul 2025561 PMAQI
13th Jul 2025532 PMAQI
13th Jul 2025443 PMAQI
13th Jul 2025424 PMAQI
13th Jul 2025375 PMAQI
13th Jul 2025366 PMAQI
13th Jul 2025367 PMAQI
13th Jul 2025368 PMAQI
13th Jul 2025379 PMAQI
13th Jul 20253910 PMAQI
13th Jul 20254011 PMAQI
14th Jul 20254112 AMAQI
14th Jul 2025411 AMAQI
14th Jul 2025412 AMAQI
14th Jul 2025393 AMAQI
14th Jul 2025324 AMAQI
24°C21/31°C
14th Jul 2025255 AMAQI
14th Jul 2025246 AMAQI
14th Jul 2025267 AMAQI
14th Jul 2025258 AMAQI
14th Jul 2025299 AMAQI
14th Jul 20253710 AMAQI
14th Jul 20254811 AMAQI
14th Jul 20255012 PMAQI
14th Jul 2025521 PMAQI
14th Jul 2025512 PMAQI
14th Jul 2025483 PMAQI
14th Jul 2025454 PMAQI
14th Jul 2025435 PMAQI
14th Jul 2025436 PMAQI
14th Jul 2025397 PMAQI
14th Jul 2025398 PMAQI
14th Jul 2025399 PMAQI
14th Jul 20253610 PMAQI
14th Jul 20253811 PMAQI
15th Jul 20253712 AMAQI
15th Jul 2025391 AMAQI
15th Jul 2025332 AMAQI
15th Jul 2025343 AMAQI
15th Jul 2025364 AMAQI
26°C21/32°C
15th Jul 2025385 AMAQI
15th Jul 2025386 AMAQI
15th Jul 2025437 AMAQI
15th Jul 2025488 AMAQI
15th Jul 2025529 AMAQI
15th Jul 20254910 AMAQI
15th Jul 20254611 AMAQI
15th Jul 20254412 PMAQI
15th Jul 2025411 PMAQI
15th Jul 2025412 PMAQI
15th Jul 2025413 PMAQI
15th Jul 2025414 PMAQI
15th Jul 2025415 PMAQI
15th Jul 2025406 PMAQI
15th Jul 2025407 PMAQI
15th Jul 2025418 PMAQI
15th Jul 2025389 PMAQI
15th Jul 20253610 PMAQI
15th Jul 20253811 PMAQI
16th Jul 20253712 AMAQI
16th Jul 2025351 AMAQI
16th Jul 2025282 AMAQI
16th Jul 2025263 AMAQI
16th Jul 2025264 AMAQI
25°C20/30°C
16th Jul 2025275 AMAQI
16th Jul 2025286 AMAQI
16th Jul 2025307 AMAQI
16th Jul 2025318 AMAQI
16th Jul 2025369 AMAQI
16th Jul 20253610 AMAQI
16th Jul 20253711 AMAQI
16th Jul 20253812 PMAQI
16th Jul 2025391 PMAQI
16th Jul 2025412 PMAQI
16th Jul 2025403 PMAQI
16th Jul 2025404 PMAQI
16th Jul 2025425 PMAQI
16th Jul 2025386 PMAQI
16th Jul 2025337 PMAQI
16th Jul 2025338 PMAQI
16th Jul 2025329 PMAQI
16th Jul 20253010 PMAQI
16th Jul 20253011 PMAQI
17th Jul 20252912 AMAQI
17th Jul 2025291 AMAQI
17th Jul 2025242 AMAQI
17th Jul 2025243 AMAQI
17th Jul 2025244 AMAQI
26°C20/35°C
17th Jul 2025255 AMAQI
17th Jul 2025266 AMAQI
17th Jul 2025267 AMAQI
17th Jul 2025258 AMAQI
17th Jul 2025259 AMAQI
17th Jul 20252610 AMAQI
17th Jul 20252711 AMAQI
17th Jul 20252712 PMAQI
17th Jul 2025281 PMAQI
17th Jul 2025282 PMAQI
17th Jul 2025293 PMAQI
17th Jul 2025284 PMAQI
17th Jul 2025285 PMAQI
17th Jul 2025286 PMAQI
17th Jul 2025287 PMAQI
17th Jul 2025278 PMAQI
17th Jul 2025279 PMAQI
17th Jul 20252710 PMAQI
17th Jul 20252811 PMAQI
18th Jul 20252912 AMAQI
18th Jul 2025301 AMAQI
18th Jul 2025302 AMAQI
18th Jul 2025303 AMAQI
18th Jul 2025294 AMAQI
26°C21/30°C
18th Jul 2025265 AMAQI
18th Jul 2025236 AMAQI
18th Jul 2025227 AMAQI
18th Jul 2025218 AMAQI
18th Jul 2025229 AMAQI
18th Jul 20252210 AMAQI
18th Jul 20252211 AMAQI
18th Jul 20252312 PMAQI
18th Jul 2025251 PMAQI
18th Jul 2025292 PMAQI
18th Jul 2025313 PMAQI
18th Jul 2025344 PMAQI
18th Jul 2025355 PMAQI
18th Jul 2025336 PMAQI
18th Jul 2025297 PMAQI
18th Jul 2025308 PMAQI
18th Jul 2025309 PMAQI
18th Jul 20253010 PMAQI
18th Jul 20253211 PMAQI
19th Jul 20253212 AMAQI
19th Jul 2025341 AMAQI
19th Jul 2025402 AMAQI
19th Jul 2025443 AMAQI
19th Jul 2025504 AMAQI
24°C19/29°C
19th Jul 2025505 AMAQI
19th Jul 2025466 AMAQI
19th Jul 2025477 AMAQI
19th Jul 2025458 AMAQI
19th Jul 2025419 AMAQI
19th Jul 20254210 AMAQI
19th Jul 20254011 AMAQI
19th Jul 20253612 PMAQI
19th Jul 2025361 PMAQI
19th Jul 2025332 PMAQI
19th Jul 2025343 PMAQI
19th Jul 2025314 PMAQI
19th Jul 2025315 PMAQI
19th Jul 2025296 PMAQI
19th Jul 2025367 PMAQI
19th Jul 2025388 PMAQI
19th Jul 2025339 PMAQI
19th Jul 20253510 PMAQI
19th Jul 20253511 PMAQI
20th Jul 20253512 AMAQI
20th Jul 2025371 AMAQI
20th Jul 2025382 AMAQI
20th Jul 2025393 AMAQI
20th Jul 2025394 AMAQI
25°C21/30°C
20th Jul 2025405 AMAQI
20th Jul 2025426 AMAQI
20th Jul 2025447 AMAQI
20th Jul 2025468 AMAQI
20th Jul 2025479 AMAQI
20th Jul 20254110 AMAQI
20th Jul 20253111 AMAQI
20th Jul 20252812 PMAQI
20th Jul 2025241 PMAQI
20th Jul 2025282 PMAQI
20th Jul 2025343 PMAQI
20th Jul 2025334 PMAQI
20th Jul 2025335 PMAQI
20th Jul 2025336 PMAQI
20th Jul 2025347 PMAQI
20th Jul 2025358 PMAQI
20th Jul 2025349 PMAQI
20th Jul 20253310 PMAQI
20th Jul 20253111 PMAQI
21st Jul 20253112 AMAQI
21st Jul 2025361 AMAQI
21st Jul 2025212 AMAQI
21st Jul 2025223 AMAQI
21st Jul 2025234 AMAQI
26°C22/31°C
21st Jul 2025235 AMAQI
21st Jul 2025246 AMAQI
21st Jul 2025257 AMAQI
21st Jul 2025248 AMAQI
21st Jul 2025269 AMAQI
21st Jul 20252710 AMAQI
21st Jul 20252911 AMAQI
21st Jul 20252612 PMAQI
21st Jul 2025291 PMAQI
21st Jul 2025322 PMAQI
21st Jul 2025323 PMAQI
21st Jul 2025364 PMAQI
21st Jul 2025365 PMAQI
21st Jul 2025346 PMAQI
21st Jul 2025287 PMAQI
21st Jul 2025298 PMAQI
21st Jul 2025339 PMAQI
21st Jul 20253210 PMAQI
21st Jul 20253411 PMAQI
22nd Jul 20253412 AMAQI
22nd Jul 2025321 AMAQI
22nd Jul 2025332 AMAQI
22nd Jul 2025313 AMAQI
22nd Jul 2025344 AMAQI
24°C23/27°C
22nd Jul 2025355 AMAQI
22nd Jul 2025426 AMAQI
22nd Jul 2025357 AMAQI
22nd Jul 2025378 AMAQI
22nd Jul 2025429 AMAQI
22nd Jul 20254410 AMAQI
22nd Jul 20254811 AMAQI
22nd Jul 20254612 PMAQI
22nd Jul 2025451 PMAQI
22nd Jul 2025462 PMAQI
22nd Jul 2025463 PMAQI
22nd Jul 2025444 PMAQI
22nd Jul 2025455 PMAQI
22nd Jul 2025456 PMAQI
22nd Jul 2025427 PMAQI
22nd Jul 2025448 PMAQI
22nd Jul 2025489 PMAQI
22nd Jul 20255010 PMAQI
22nd Jul 20254911 PMAQI
23rd Jul 20255212 AMAQI
23rd Jul 2025521 AMAQI
23rd Jul 2025552 AMAQI
23rd Jul 2025553 AMAQI
23rd Jul 2025564 AMAQI
26°C21/33°C
23rd Jul 2025575 AMAQI
23rd Jul 2025586 AMAQI
23rd Jul 2025587 AMAQI
23rd Jul 2025588 AMAQI
23rd Jul 2025589 AMAQI
23rd Jul 20255810 AMAQI
23rd Jul 20255811 AMAQI
23rd Jul 20255812 PMAQI
23rd Jul 2025591 PMAQI
23rd Jul 2025592 PMAQI
23rd Jul 2025603 PMAQI
23rd Jul 2025594 PMAQI
23rd Jul 2025605 PMAQI
23rd Jul 2025596 PMAQI
23rd Jul 2025587 PMAQI
23rd Jul 2025578 PMAQI
23rd Jul 2025589 PMAQI
23rd Jul 20255510 PMAQI
23rd Jul 20255611 PMAQI
24th Jul 20255612 AMAQI
24th Jul 2025541 AMAQI
24th Jul 2025512 AMAQI
24th Jul 2025523 AMAQI
24th Jul 2025544 AMAQI
27°C23/33°C
24th Jul 2025545 AMAQI
24th Jul 2025546 AMAQI
24th Jul 2025557 AMAQI
24th Jul 2025558 AMAQI
24th Jul 2025559 AMAQI
24th Jul 20255610 AMAQI
24th Jul 20255611 AMAQI
24th Jul 20255512 PMAQI
24th Jul 2025551 PMAQI
24th Jul 2025552 PMAQI
24th Jul 2025553 PMAQI
24th Jul 2025554 PMAQI
24th Jul 2025555 PMAQI
24th Jul 2025556 PMAQI
24th Jul 2025557 PMAQI
24th Jul 2025558 PMAQI
24th Jul 2025549 PMAQI
24th Jul 20255410 PMAQI
24th Jul 20255511 PMAQI
25th Jul 20255512 AMAQI
25th Jul 2025541 AMAQI
25th Jul 2025522 AMAQI
25th Jul 2025503 AMAQI
25th Jul 2025454 AMAQI
28°C23/33°C
25th Jul 2025305 AMAQI
25th Jul 2025286 AMAQI
25th Jul 2025327 AMAQI
25th Jul 2025318 AMAQI
25th Jul 2025319 AMAQI
25th Jul 20253010 AMAQI
25th Jul 20252911 AMAQI
25th Jul 20252912 PMAQI
25th Jul 2025341 PMAQI
25th Jul 2025372 PMAQI
25th Jul 2025423 PMAQI
25th Jul 2025434 PMAQI
25th Jul 2025435 PMAQI
25th Jul 2025426 PMAQI
25th Jul 2025437 PMAQI
25th Jul 2025438 PMAQI
25th Jul 2025439 PMAQI
25th Jul 20254510 PMAQI
25th Jul 20254611 PMAQI
26th Jul 20254712 AMAQI
26th Jul 2025461 AMAQI
26th Jul 2025382 AMAQI
26th Jul 2025333 AMAQI
26th Jul 2025364 AMAQI
27°C23/33°C
26th Jul 2025335 AMAQI
26th Jul 2025346 AMAQI
26th Jul 2025357 AMAQI
26th Jul 2025348 AMAQI
26th Jul 2025379 AMAQI
26th Jul 20254310 AMAQI
26th Jul 20254611 AMAQI
26th Jul 20254312 PMAQI
26th Jul 2025421 PMAQI
26th Jul 2025402 PMAQI
26th Jul 2025403 PMAQI
26th Jul 2025394 PMAQI
26th Jul 2025385 PMAQI
26th Jul 2025386 PMAQI
26th Jul 2025407 PMAQI
26th Jul 2025408 PMAQI
26th Jul 2025379 PMAQI
26th Jul 20253810 PMAQI
26th Jul 20253611 PMAQI
27th Jul 20253612 AMAQI
27th Jul 2025331 AMAQI
27th Jul 2025222 AMAQI
27th Jul 2025203 AMAQI
27th Jul 2025184 AMAQI
28°C24/32°C
27th Jul 2025185 AMAQI
27th Jul 2025196 AMAQI
27th Jul 2025197 AMAQI
27th Jul 2025208 AMAQI
27th Jul 2025209 AMAQI
27th Jul 20251910 AMAQI
27th Jul 20252011 AMAQI
27th Jul 20252212 PMAQI
27th Jul 2025241 PMAQI
27th Jul 2025272 PMAQI
27th Jul 2025283 PMAQI
27th Jul 2025304 PMAQI
27th Jul 2025325 PMAQI
27th Jul 2025326 PMAQI
27th Jul 2025287 PMAQI
27th Jul 2025298 PMAQI
27th Jul 2025359 PMAQI
27th Jul 20253210 PMAQI
27th Jul 20253211 PMAQI
28th Jul 20253112 AMAQI
28th Jul 2025291 AMAQI
28th Jul 2025302 AMAQI
28th Jul 2025323 AMAQI
28th Jul 2025324 AMAQI
27°C23/33°C
28th Jul 2025315 AMAQI
28th Jul 2025326 AMAQI
28th Jul 2025327 AMAQI
28th Jul 2025328 AMAQI
28th Jul 2025299 AMAQI
28th Jul 20252910 AMAQI
28th Jul 20253211 AMAQI
28th Jul 20253012 PMAQI
28th Jul 2025301 PMAQI
28th Jul 2025312 PMAQI
28th Jul 2025333 PMAQI
28th Jul 2025324 PMAQI
28th Jul 2025325 PMAQI
28th Jul 2025326 PMAQI
28th Jul 2025317 PMAQI
28th Jul 2025318 PMAQI
28th Jul 2025309 PMAQI
28th Jul 20253010 PMAQI
28th Jul 20253011 PMAQI
29th Jul 20253212 AMAQI
29th Jul 2025311 AMAQI
29th Jul 2025292 AMAQI
29th Jul 2025273 AMAQI
29th Jul 2025254 AMAQI
29°C24/35°C
29th Jul 2025285 AMAQI
29th Jul 2025286 AMAQI
29th Jul 2025287 AMAQI
29th Jul 2025288 AMAQI
29th Jul 2025289 AMAQI
29th Jul 20253010 AMAQI
29th Jul 20253111 AMAQI
29th Jul 20253312 PMAQI
29th Jul 2025341 PMAQI
29th Jul 2025352 PMAQI
29th Jul 2025343 PMAQI
29th Jul 2025354 PMAQI
29th Jul 2025355 PMAQI
29th Jul 2025346 PMAQI
29th Jul 2025327 PMAQI
29th Jul 2025308 PMAQI
29th Jul 2025349 PMAQI
29th Jul 20253310 PMAQI
29th Jul 20253511 PMAQI
30th Jul 20253512 AMAQI
30th Jul 2025361 AMAQI
30th Jul 2025362 AMAQI
30th Jul 2025373 AMAQI
30th Jul 2025374 AMAQI
28°C20/35°C
30th Jul 2025375 AMAQI
30th Jul 2025386 AMAQI
30th Jul 2025407 AMAQI
30th Jul 2025398 AMAQI
30th Jul 2025399 AMAQI
30th Jul 20254410 AMAQI
30th Jul 20254211 AMAQI
30th Jul 20254212 PMAQI
30th Jul 2025431 PMAQI
30th Jul 2025402 PMAQI
30th Jul 2025413 PMAQI
30th Jul 2025414 PMAQI
30th Jul 2025415 PMAQI
30th Jul 2025416 PMAQI
30th Jul 2025417 PMAQI
30th Jul 2025418 PMAQI
30th Jul 2025359 PMAQI
30th Jul 20253410 PMAQI
30th Jul 20253411 PMAQI
31st Jul 20253312 AMAQI
31st Jul 2025311 AMAQI
31st Jul 2025242 AMAQI
31st Jul 2025253 AMAQI
31st Jul 2025234 AMAQI
27°C22/33°C
31st Jul 2025245 AMAQI
31st Jul 2025326 AMAQI
31st Jul 2025377 AMAQI
31st Jul 2025438 AMAQI
31st Jul 2025449 AMAQI
31st Jul 20254810 AMAQI
31st Jul 20255411 AMAQI
31st Jul 20255312 PMAQI
31st Jul 2025521 PMAQI
31st Jul 2025582 PMAQI
31st Jul 2025623 PMAQI
31st Jul 2025574 PMAQI
31st Jul 2025585 PMAQI
31st Jul 2025586 PMAQI
31st Jul 2025317 PMAQI
31st Jul 2025568 PMAQI
31st Jul 2025789 PMAQI
31st Jul 202510810 PMAQI
31st Jul 202511611 PMAQI
1st Aug 202512412 AMAQI
1st Aug 20251151 AMAQI
1st Aug 20251262 AMAQI
1st Aug 20251113 AMAQI
1st Aug 20251174 AMAQI
22°C19/26°C
1st Aug 20251115 AMAQI
1st Aug 20251276 AMAQI
1st Aug 20251227 AMAQI
1st Aug 20251218 AMAQI
1st Aug 20251249 AMAQI
1st Aug 202510210 AMAQI
1st Aug 202510511 AMAQI
1st Aug 202510812 PMAQI
1st Aug 20251071 PMAQI
1st Aug 20251062 PMAQI
1st Aug 20251023 PMAQI
1st Aug 2025994 PMAQI
1st Aug 2025995 PMAQI
1st Aug 2025986 PMAQI
1st Aug 20251227 PMAQI
1st Aug 20251178 PMAQI
1st Aug 20251059 PMAQI
1st Aug 202511210 PMAQI
1st Aug 202510111 PMAQI
2nd Aug 202510112 AMAQI
2nd Aug 20251041 AMAQI
2nd Aug 20251002 AMAQI
2nd Aug 2025973 AMAQI
2nd Aug 2025984 AMAQI
20°C13/28°C
2nd Aug 2025965 AMAQI
2nd Aug 2025986 AMAQI
2nd Aug 20251017 AMAQI
2nd Aug 20251008 AMAQI
2nd Aug 2025989 AMAQI
2nd Aug 20259310 AMAQI
2nd Aug 20259211 AMAQI
2nd Aug 20257912 PMAQI
2nd Aug 2025711 PMAQI
2nd Aug 2025662 PMAQI
2nd Aug 2025643 PMAQI
2nd Aug 2025624 PMAQI
2nd Aug 2025605 PMAQI
2nd Aug 2025596 PMAQI
2nd Aug 2025887 PMAQI
2nd Aug 2025778 PMAQI
2nd Aug 2025609 PMAQI
2nd Aug 20255610 PMAQI
2nd Aug 20255711 PMAQI
3rd Aug 20255812 AMAQI
3rd Aug 2025561 AMAQI
3rd Aug 2025562 AMAQI
3rd Aug 2025613 AMAQI
3rd Aug 2025604 AMAQI
19°C12/27°C
3rd Aug 2025605 AMAQI
3rd Aug 2025626 AMAQI
3rd Aug 2025597 AMAQI
3rd Aug 2025608 AMAQI
3rd Aug 2025629 AMAQI
3rd Aug 20255910 AMAQI
3rd Aug 20255711 AMAQI
3rd Aug 20255312 PMAQI
3rd Aug 2025491 PMAQI
3rd Aug 2025482 PMAQI
3rd Aug 2025473 PMAQI
3rd Aug 2025504 PMAQI
3rd Aug 2025485 PMAQI
3rd Aug 2025446 PMAQI
3rd Aug 2025567 PMAQI
3rd Aug 2025508 PMAQI
3rd Aug 2025449 PMAQI
3rd Aug 20254510 PMAQI
3rd Aug 20254211 PMAQI
4th Aug 20254512 AMAQI
4th Aug 2025461 AMAQI
4th Aug 2025422 AMAQI
4th Aug 2025523 AMAQI
4th Aug 2025504 AMAQI
20°C12/27°C
4th Aug 2025525 AMAQI
4th Aug 2025486 AMAQI
4th Aug 2025487 AMAQI
4th Aug 2025518 AMAQI
4th Aug 2025529 AMAQI
4th Aug 20255410 AMAQI
4th Aug 20255411 AMAQI
4th Aug 20255312 PMAQI
4th Aug 2025531 PMAQI
4th Aug 2025512 PMAQI
4th Aug 2025503 PMAQI
4th Aug 2025444 PMAQI
4th Aug 2025445 PMAQI
4th Aug 2025426 PMAQI
4th Aug 2025487 PMAQI
4th Aug 2025448 PMAQI
4th Aug 2025439 PMAQI
4th Aug 20254510 PMAQI
4th Aug 20254811 PMAQI
5th Aug 20254812 AMAQI
5th Aug 2025491 AMAQI
5th Aug 2025512 AMAQI
5th Aug 2025513 AMAQI
5th Aug 2025504 AMAQI
21°C14/28°C
5th Aug 2025525 AMAQI
5th Aug 2025516 AMAQI
5th Aug 2025497 AMAQI
5th Aug 2025528 AMAQI
5th Aug 2025559 AMAQI
5th Aug 20255910 AMAQI
5th Aug 20255811 AMAQI
5th Aug 20255712 PMAQI
5th Aug 2025561 PMAQI
5th Aug 2025572 PMAQI
5th Aug 2025623 PMAQI
5th Aug 2025604 PMAQI
5th Aug 2025615 PMAQI
5th Aug 2025556 PMAQI
5th Aug 2025537 PMAQI
5th Aug 2025558 PMAQI
5th Aug 2025589 PMAQI
5th Aug 20255910 PMAQI
5th Aug 20256211 PMAQI
6th Aug 20256412 AMAQI
6th Aug 2025641 AMAQI
6th Aug 2025642 AMAQI
6th Aug 2025643 AMAQI
6th Aug 2025644 AMAQI
22°C16/29°C
6th Aug 2025605 AMAQI
6th Aug 2025626 AMAQI
6th Aug 2025637 AMAQI
6th Aug 2025668 AMAQI
6th Aug 2025609 AMAQI
6th Aug 20255510 AMAQI
6th Aug 20255411 AMAQI
6th Aug 20255212 PMAQI
6th Aug 2025521 PMAQI
6th Aug 2025502 PMAQI
6th Aug 2025483 PMAQI
6th Aug 2025504 PMAQI
6th Aug 2025505 PMAQI
6th Aug 2025426 PMAQI
6th Aug 2025527 PMAQI
6th Aug 2025498 PMAQI
6th Aug 2025479 PMAQI
6th Aug 20255010 PMAQI
6th Aug 20255211 PMAQI
7th Aug 20255212 AMAQI
7th Aug 2025511 AMAQI
7th Aug 2025392 AMAQI
7th Aug 2025383 AMAQI
7th Aug 2025404 AMAQI
24°C15/32°C
7th Aug 2025385 AMAQI
7th Aug 2025426 AMAQI
7th Aug 2025487 AMAQI
7th Aug 2025508 AMAQI
7th Aug 2025539 AMAQI
7th Aug 20255210 AMAQI
7th Aug 20255311 AMAQI
7th Aug 20255412 PMAQI
7th Aug 2025541 PMAQI
7th Aug 2025542 PMAQI
7th Aug 2025543 PMAQI
7th Aug 2025534 PMAQI
7th Aug 2025545 PMAQI
7th Aug 2025546 PMAQI
7th Aug 2025527 PMAQI
7th Aug 2025508 PMAQI
7th Aug 2025479 PMAQI
7th Aug 20255010 PMAQI
7th Aug 20255011 PMAQI
8th Aug 20255112 AMAQI
8th Aug 2025511 AMAQI
8th Aug 2025512 AMAQI
8th Aug 2025523 AMAQI
8th Aug 2025524 AMAQI
25°C20/31°C
8th Aug 2025535 AMAQI
8th Aug 2025546 AMAQI
8th Aug 2025537 AMAQI
8th Aug 2025548 AMAQI
8th Aug 2025549 AMAQI
8th Aug 20255610 AMAQI
8th Aug 20255611 AMAQI
8th Aug 20255612 PMAQI
8th Aug 2025561 PMAQI
8th Aug 2025542 PMAQI
8th Aug 2025553 PMAQI
8th Aug 2025544 PMAQI
8th Aug 2025555 PMAQI
8th Aug 2025556 PMAQI
8th Aug 2025547 PMAQI
8th Aug 2025548 PMAQI
8th Aug 2025569 PMAQI
8th Aug 20255610 PMAQI
8th Aug 20255611 PMAQI
9th Aug 20255612 AMAQI
9th Aug 2025561 AMAQI
9th Aug 2025562 AMAQI
9th Aug 2025563 AMAQI
9th Aug 2025564 AMAQI
27°C21/34°C
9th Aug 2025565 AMAQI
9th Aug 2025556 AMAQI
9th Aug 2025557 AMAQI
9th Aug 2025558 AMAQI
9th Aug 2025549 AMAQI
9th Aug 20255410 AMAQI
9th Aug 20255211 AMAQI
9th Aug 20255212 PMAQI
9th Aug 2025521 PMAQI
9th Aug 2025532 PMAQI
9th Aug 2025543 PMAQI
9th Aug 2025534 PMAQI
9th Aug 2025545 PMAQI
9th Aug 2025546 PMAQI
9th Aug 2025557 PMAQI
9th Aug 2025558 PMAQI
9th Aug 2025549 PMAQI
9th Aug 20255410 PMAQI
9th Aug 20255411 PMAQI
10th Aug 20255412 AMAQI
10th Aug 2025541 AMAQI
10th Aug 2025512 AMAQI
10th Aug 2025523 AMAQI
10th Aug 2025524 AMAQI
27°C20/34°C
10th Aug 2025495 AMAQI
10th Aug 2025516 AMAQI
10th Aug 2025527 AMAQI
10th Aug 2025518 AMAQI
10th Aug 2025519 AMAQI
10th Aug 20255010 AMAQI
10th Aug 20254911 AMAQI
10th Aug 20254712 PMAQI
10th Aug 2025461 PMAQI
10th Aug 2025482 PMAQI
10th Aug 2025503 PMAQI
10th Aug 2025514 PMAQI
10th Aug 2025515 PMAQI
10th Aug 2025516 PMAQI
10th Aug 2025527 PMAQI
10th Aug 2025518 PMAQI
10th Aug 2025519 PMAQI
10th Aug 20255210 PMAQI
10th Aug 20255111 PMAQI
11th Aug 20255212 AMAQI
11th Aug 2025481 AMAQI
11th Aug 2025482 AMAQI
11th Aug 2025463 AMAQI
11th Aug 2025444 AMAQI
27°C21/34°C
11th Aug 2025425 AMAQI
5 AM11th Aug 2025446 AMAQI
11th Aug 2025437 AMAQI
11th Aug 2025458 AMAQI
11th Aug 2025519 AMAQI
11th Aug 20255210 AMAQI
11th Aug 20255211 AMAQI
11th Aug 20255312 PMAQI
12 PM8 PM
12 AM
4 AM
--°C/°C
Day time
Avg. Highest Time
5 AM - 8 PM
46AQI
16 hours / Day
480 hours / Month
Avg. Lowest Time
5 AM - 8 PM
46AQI
16 hours / Day
480 hours / Month
In the last 30 days, during the daytime, the highest AQI was between 5 AM to 8 PM (Avg. 46), while the lowest AQI was between 5 AM to 8 PM (Avg. 46).
Night time
Avg. Highest Time
12 AM - 1 AM
47AQI
2 hours / Day
60 hours / Month
Avg. Lowest Time
2 AM - 11 PM
45AQI
6 hours / Day
180 hours / Month
In the last 30 days, during the daytime, the highest AQI was between 12 AM to 1 AM (Avg. 47), while the lowest AQI was between 2 AM to 11 PM (Avg. 45).
2025 Days Vs Air Quality
Illinois 121, Decatur, Illinois, United States
2025
80%
109
20%
27
0.7%
1
Total number of days with different AQI categories in last 223 days in 2025 (142 days remaining)
Good
109 DaysModerate
27 DaysPoor
1 DaysUnhealthy
0 DaysSevere
0 DaysHazardous
0 DaysUnder WHO’s Safe Air Quality Limits: 80%
Health Risk Level:
Low
In 2025, 80% of 223 days were within WHO’s safe air quality limits. The risk of health issues is Low, but the long-term effects, especially on vulnerable individuals, remain uncertain.
Annual Air Quality Insights
Illinois 121, Decatur, Illinois, United States
AQI levels in 2025
AQI
PM2.5
PM10
CO
SO2
NO2
O3
Sun.Mon.Tue.Wed.Thu.Fri.Sat.
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
1st March 2025
40AQI
40AQI
2nd March 2025
40AQI
40AQI
3rd March 2025
43AQI
43AQI
4th March 2025
31AQI
31AQI
5th March 2025
17AQI
17AQI
1st April 2025
27AQI
27AQI
2nd April 2025
27AQI
27AQI
3rd April 2025
23AQI
23AQI
4th April 2025
34AQI
34AQI
5th April 2025
20AQI
20AQI
6th April 2025
20AQI
20AQI
7th April 2025
27AQI
27AQI
8th April 2025
18AQI
18AQI
9th April 2025
23AQI
23AQI
10th April 2025
34AQI
34AQI
11th April 2025
42AQI
42AQI
12th April 2025
40AQI
40AQI
13th April 2025
35AQI
35AQI
14th April 2025
35AQI
35AQI
15th April 2025
20AQI
20AQI
16th April 2025
28AQI
28AQI
17th April 2025
39AQI
39AQI
18th April 2025
53AQI
53AQI
19th April 2025
50AQI
50AQI
20th April 2025
39AQI
39AQI
21st April 2025
18AQI
18AQI
22nd April 2025
24AQI
24AQI
23rd April 2025
27AQI
27AQI
24th April 2025
36AQI
36AQI
25th April 2025
35AQI
35AQI
26th April 2025
23AQI
23AQI
27th April 2025
19AQI
19AQI
28th April 2025
32AQI
32AQI
29th April 2025
32AQI
32AQI
30th April 2025
25AQI
25AQI
1st May 2025
24AQI
24AQI
2nd May 2025
22AQI
22AQI
3rd May 2025
23AQI
23AQI
4th May 2025
17AQI
17AQI
5th May 2025
23AQI
23AQI
6th May 2025
27AQI
27AQI
7th May 2025
24AQI
24AQI
8th May 2025
26AQI
26AQI
9th May 2025
25AQI
25AQI
10th May 2025
32AQI
32AQI
11th May 2025
26AQI
26AQI
12th May 2025
31AQI
31AQI
13th May 2025
22AQI
22AQI
14th May 2025
28AQI
28AQI
15th May 2025
49AQI
49AQI
16th May 2025
35AQI
35AQI
17th May 2025
20AQI
20AQI
18th May 2025
18AQI
18AQI
19th May 2025
26AQI
26AQI
20th May 2025
24AQI
24AQI
21st May 2025
14AQI
14AQI
22nd May 2025
14AQI
14AQI
23rd May 2025
19AQI
19AQI
24th May 2025
24AQI
24AQI
25th May 2025
26AQI
26AQI
26th May 2025
19AQI
19AQI
27th May 2025
20AQI
20AQI
28th May 2025
27AQI
27AQI
29th May 2025
38AQI
38AQI
30th May 2025
31AQI
31AQI
31st May 2025
46AQI
46AQI
1st June 2025
31AQI
31AQI
2nd June 2025
44AQI
44AQI
3rd June 2025
57AQI
57AQI
4th June 2025
44AQI
44AQI
5th June 2025
47AQI
47AQI
6th June 2025
62AQI
62AQI
7th June 2025
67AQI
67AQI
8th June 2025
61AQI
61AQI
9th June 2025
59AQI
59AQI
10th June 2025
55AQI
55AQI
11th June 2025
64AQI
64AQI
12th June 2025
79AQI
79AQI
13th June 2025
69AQI
69AQI
14th June 2025
49AQI
49AQI
15th June 2025
42AQI
42AQI
16th June 2025
39AQI
39AQI
17th June 2025
27AQI
27AQI
18th June 2025
37AQI
37AQI
19th June 2025
23AQI
23AQI
20th June 2025
33AQI
33AQI
21st June 2025
42AQI
42AQI
22nd June 2025
46AQI
46AQI
23rd June 2025
57AQI
57AQI
24th June 2025
53AQI
53AQI
25th June 2025
51AQI
51AQI
26th June 2025
51AQI
51AQI
27th June 2025
35AQI
35AQI
28th June 2025
28AQI
28AQI
29th June 2025
32AQI
32AQI
30th June 2025
28AQI
28AQI
1st July 2025
28AQI
28AQI
2nd July 2025
42AQI
42AQI
3rd July 2025
49AQI
49AQI
4th July 2025
54AQI
54AQI
5th July 2025
65AQI
65AQI
6th July 2025
57AQI
57AQI
7th July 2025
45AQI
45AQI
8th July 2025
65AQI
65AQI
9th July 2025
40AQI
40AQI
10th July 2025
38AQI
38AQI
11th July 2025
45AQI
45AQI
12th July 2025
34AQI
34AQI
13th July 2025
39AQI
39AQI
14th July 2025
39AQI
39AQI
15th July 2025
40AQI
40AQI
16th July 2025
33AQI
33AQI
17th July 2025
27AQI
27AQI
18th July 2025
28AQI
28AQI
19th July 2025
38AQI
38AQI
20th July 2025
36AQI
36AQI
21st July 2025
29AQI
29AQI
22nd July 2025
41AQI
41AQI
23rd July 2025
57AQI
57AQI
24th July 2025
54AQI
54AQI
25th July 2025
41AQI
41AQI
26th July 2025
39AQI
39AQI
27th July 2025
26AQI
26AQI
28th July 2025
31AQI
31AQI
29th July 2025
31AQI
31AQI
30th July 2025
39AQI
39AQI
31st July 2025
50AQI
50AQI
1st August 2025
112AQI
112AQI
2nd August 2025
83AQI
83AQI
3rd August 2025
53AQI
53AQI
4th August 2025
48AQI
48AQI
5th August 2025
55AQI
55AQI
6th August 2025
55AQI
55AQI
7th August 2025
49AQI
49AQI
8th August 2025
54AQI
54AQI
9th August 2025
54AQI
54AQI
10th August 2025
51AQI
51AQI
34AQI
30AQI
26AQI
47AQI
41AQI
61AQI
No. of days
Jan.Feb.Mar.Apr.MayJun.Jul.Aug.Sep.Oct.Nov.Dec.Total Days
202538AQI
5
29
1
31
17
13
25
6
2
7
1
109
27
1
Highest AQI recorded in
August61AQI
Lowest AQI recorded in
May26AQI
Most & Least Polluted Years Over the Last 1 Years
Most Polluted Year Recorded
2025(Avg.)
38AQILeast Polluted Year Recorded
2025(Avg.)
38AQIIllinois 121's annual 2025 AQI (38) shows an average percentage change of NaN% (improved AQI) compared to previous years: .
