Cornwall, Ontario, Canada Historical Air Quality Analysis
Dive into detailed Air Quality Insights with historical data, monthly patterns, and yearly trends at your fingertips!
August Air Quality Analysis
Cornwall, Ontario, Canada
AQI Trends: Highest and Lowest
Same Day Analysis (20th August ):
On this day, AQI across the 5 years varied significantly: 2025 ranks 3rd highest AQI at 22 of Good air quality, showing improvement over 2023 and 2021 on the same day.
Download 2024 Annual Data
World Air Quality Report

Day & Night AQI Trend: 20th Aug - 21st Aug 2025
Cornwall, Ontario, Canada
5 AM20th Aug 2025
8 PM
4 AM21st Aug 2025
23AQI
19AQI
20AQI
17AQI
In the last 24 hours,
Cornwall's AQI reached its highest point of 23 at 1 PM during the Day, while the lowest point, 17, was recorded at 2 AM during the Night between 20th Aug and 21st Aug 2025.
Day & Night AQI Trend : Jul - Aug 2025
Cornwall, Ontario, Canada
17°C6/24°C
21°C12/28°C
27°C18/34°C
25°C21/29°C
24°C13/32°C
26°C21/32°C
26°C19/34°C
25°C20/31°C
23°C17/31°C
19°C15/24°C
18°C10/25°C
19°C8/29°C
23°C15/32°C
22°C15/30°C
20°C13/28°C
21°C11/30°C
23°C13/32°C
25°C16/33°C
26°C18/34°C
29°C21/35°C
28°C22/35°C
28°C19/36°C
26°C20/33°C
23°C16/31°C
20°C10/29°C
25°C12/34°C
20°C14/22°C
14°C5/21°C
17°C9/26°C
18°C15/23°C
--°C/°C
47AQI
47AQI
46AQI
45AQI
2025 Days Vs Air Quality
Cornwall, Ontario, Canada
89%
206
11%
26
Total number of days with different AQI categories in last 233 days in 2025 (132 days remaining)
Under WHO’s Safe Air Quality Limits: 89%
Health Risk Level:
Low
In 2025, 89% of 233 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
Cornwall, Ontario, Canada
AQI levels in 2025
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
22AQI
22AQI
23AQI
25AQI
25AQI
23AQI
23AQI
24AQI
26AQI
31AQI
32AQI
35AQI
46AQI
24AQI
23AQI
33AQI
49AQI
30AQI
23AQI
28AQI
29AQI
31AQI
33AQI
38AQI
41AQI
38AQI
29AQI
29AQI
27AQI
27AQI
46AQI
29AQI
30AQI
54AQI
25AQI
24AQI
31AQI
32AQI
26AQI
28AQI
26AQI
28AQI
30AQI
27AQI
28AQI
28AQI
26AQI
24AQI
21AQI
20AQI
23AQI
27AQI
42AQI
50AQI
43AQI
60AQI
35AQI
30AQI
32AQI
29AQI
29AQI
33AQI
40AQI
53AQI
26AQI
30AQI
32AQI
30AQI
29AQI
36AQI
29AQI
41AQI
64AQI
60AQI
33AQI
18AQI
23AQI
38AQI
33AQI
16AQI
24AQI
19AQI
25AQI
22AQI
20AQI
17AQI
18AQI
19AQI
25AQI
29AQI
17AQI
18AQI
19AQI
18AQI
26AQI
16AQI
20AQI
18AQI
17AQI
22AQI
32AQI
40AQI
25AQI
26AQI
24AQI
21AQI
15AQI
21AQI
34AQI
19AQI
19AQI
18AQI
14AQI
22AQI
24AQI
21AQI
12AQI
16AQI
29AQI
17AQI
22AQI
22AQI
14AQI
20AQI
19AQI
17AQI
16AQI
16AQI
21AQI
17AQI
17AQI
20AQI
28AQI
32AQI
27AQI
30AQI
28AQI
16AQI
12AQI
13AQI
18AQI
13AQI
15AQI
13AQI
16AQI
19AQI
22AQI
28AQI
23AQI
24AQI
24AQI
13AQI
17AQI
26AQI
47AQI
48AQI
53AQI
59AQI
59AQI
58AQI
39AQI
49AQI
56AQI
29AQI
29AQI
29AQI
43AQI
32AQI
23AQI
34AQI
20AQI
42AQI
46AQI
46AQI
51AQI
40AQI
26AQI
28AQI
28AQI
21AQI
28AQI
35AQI
34AQI
43AQI
29AQI
26AQI
44AQI
49AQI
27AQI
31AQI
36AQI
42AQI
49AQI
39AQI
37AQI
43AQI
54AQI
42AQI
21AQI
26AQI
35AQI
31AQI
19AQI
22AQI
29AQI
40AQI
56AQI
60AQI
58AQI
53AQI
65AQI
54AQI
26AQI
36AQI
61AQI
80AQI
48AQI
36AQI
48AQI
55AQI
60AQI
63AQI
55AQI
54AQI
53AQI
44AQI
23AQI
36AQI
28AQI
16AQI
18AQI
22AQI
30AQI
31AQI
30AQI
21AQI
20AQI
37AQI
40AQI
43AQI
No. of days
202531AQI
Highest AQI recorded in
August43AQI
Lowest AQI recorded in
May20AQI
202430AQI
Highest AQI recorded in
February37AQI
Lowest AQI recorded in
November25AQI
202337AQI
Highest AQI recorded in
June62AQI
Lowest AQI recorded in
October26AQI
202231AQI
Highest AQI recorded in
January35AQI
Lowest AQI recorded in
August22AQI
202131AQI
Highest AQI recorded in
February35AQI
Lowest AQI recorded in
November25AQI
202028AQI
Highest AQI recorded in
May37AQI
Lowest AQI recorded in
October22AQI
Most & Least Polluted Years Over the Last 6 Years
Cornwall's annual 2025 AQI (31) shows an average percentage change of -0.1% (improved AQI) compared to previous years: 2020 (28), 2021 (31), 2022 (31), 2023 (37), 2024 (30).