Chonan, Chungnam, South Korea Historical Air Quality Analysis
Dive into detailed Air Quality Insights with historical data, monthly patterns, and yearly trends at your fingertips!
September Air Quality Analysis
Chonan, Chungnam, South Korea
AQI Trends: Highest and Lowest
Same Day Analysis (17th September ):
On this day, AQI across the 5 years varied significantly: 2025 ranks 3rd highest AQI at 40 of Good air quality, showing improvement over 2024 and 2022 on the same day.
Download 2024 Annual Data
World Air Quality Report

Day & Night AQI Trend: 17th Sep - 18th Sep 2025
Chonan, Chungnam, South Korea
6 AM17th Sep 2025
6 PM
5 AM18th Sep 2025
51AQI
19AQI
47AQI
27AQI
In the last 24 hours,
Chonan's AQI reached its highest point of 51 at 6 AM during the Day, while the lowest point, 19, was recorded at 4 PM during the Day between 17th Sep and 18th Sep 2025.
Day & Night AQI Trend : Aug - Sep 2025
Chonan, Chungnam, South Korea
26°C23/31°C
27°C23/32°C
27°C23/32°C
27°C23/33°C
27°C23/32°C
27°C23/33°C
27°C23/33°C
25°C20/29°C
24°C20/31°C
25°C20/31°C
26°C23/31°C
26°C23/32°C
26°C22/33°C
25°C22/30°C
24°C20/28°C
24°C19/32°C
22°C21/25°C
25°C21/32°C
26°C23/31°C
24°C19/28°C
22°C17/27°C
22°C18/25°C
23°C18/28°C
23°C18/29°C
21°C19/25°C
23°C20/27°C
23°C20/28°C
24°C20/29°C
24°C21/29°C
22°C19/25°C
--°C/°C
47AQI
43AQI
47AQI
44AQI
2025 Days Vs Air Quality
Chonan, Chungnam, South Korea
28%
74
67%
173
5%
13
Total number of days with different AQI categories in last 261 days in 2025 (104 days remaining)
Under WHO’s Safe Air Quality Limits: 28%
Health Risk Level:
Very high
In 2025, 28% of 261 days were within WHO’s safe air quality limits. The risk of health issues is Very high, including respiratory issues, heart disease, and stress, particularly affecting vulnerable groups.
Annual Air Quality Insights
Chonan, Chungnam, South Korea
AQI levels in 2025
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
73AQI
67AQI
61AQI
62AQI
66AQI
89AQI
59AQI
68AQI
41AQI
62AQI
64AQI
85AQI
89AQI
95AQI
58AQI
71AQI
86AQI
82AQI
87AQI
121AQI
137AQI
141AQI
123AQI
124AQI
87AQI
62AQI
66AQI
53AQI
58AQI
57AQI
81AQI
88AQI
97AQI
58AQI
53AQI
48AQI
53AQI
47AQI
46AQI
55AQI
59AQI
81AQI
74AQI
54AQI
83AQI
59AQI
109AQI
53AQI
62AQI
49AQI
56AQI
55AQI
59AQI
55AQI
57AQI
55AQI
76AQI
61AQI
82AQI
99AQI
79AQI
56AQI
46AQI
43AQI
76AQI
90AQI
87AQI
105AQI
109AQI
106AQI
94AQI
96AQI
84AQI
58AQI
75AQI
64AQI
77AQI
81AQI
89AQI
92AQI
102AQI
109AQI
105AQI
125AQI
89AQI
92AQI
63AQI
52AQI
51AQI
60AQI
76AQI
79AQI
83AQI
85AQI
73AQI
68AQI
69AQI
74AQI
66AQI
74AQI
83AQI
62AQI
63AQI
45AQI
57AQI
59AQI
66AQI
80AQI
52AQI
68AQI
55AQI
49AQI
43AQI
62AQI
61AQI
53AQI
41AQI
61AQI
66AQI
59AQI
57AQI
52AQI
52AQI
47AQI
49AQI
48AQI
52AQI
67AQI
50AQI
55AQI
67AQI
69AQI
72AQI
73AQI
59AQI
49AQI
40AQI
59AQI
60AQI
45AQI
50AQI
55AQI
61AQI
50AQI
50AQI
62AQI
75AQI
76AQI
80AQI
78AQI
84AQI
92AQI
100AQI
74AQI
62AQI
56AQI
61AQI
68AQI
63AQI
63AQI
58AQI
53AQI
58AQI
69AQI
53AQI
58AQI
61AQI
62AQI
65AQI
65AQI
53AQI
52AQI
50AQI
56AQI
55AQI
47AQI
52AQI
60AQI
59AQI
51AQI
49AQI
47AQI
45AQI
51AQI
49AQI
48AQI
51AQI
58AQI
61AQI
53AQI
51AQI
53AQI
53AQI
61AQI
59AQI
47AQI
53AQI
41AQI
44AQI
35AQI
43AQI
41AQI
39AQI
48AQI
54AQI
57AQI
47AQI
43AQI
59AQI
63AQI
57AQI
57AQI
57AQI
62AQI
61AQI
52AQI
51AQI
47AQI
48AQI
54AQI
53AQI
53AQI
56AQI
47AQI
40AQI
40AQI
38AQI
37AQI
41AQI
50AQI
44AQI
46AQI
47AQI
47AQI
49AQI
52AQI
47AQI
43AQI
50AQI
53AQI
46AQI
43AQI
48AQI
40AQI
47AQI
50AQI
43AQI
40AQI
38AQI
40AQI
48AQI
51AQI
49AQI
49AQI
46AQI
38AQI
41AQI
49AQI
43AQI
40AQI
80AQI
64AQI
82AQI
64AQI
59AQI
61AQI
51AQI
48AQI
44AQI
No. of days
202562AQI
Highest AQI recorded in
March82AQI
Lowest AQI recorded in
September44AQI
202464AQI
Highest AQI recorded in
January83AQI
Lowest AQI recorded in
July42AQI
202372AQI
Highest AQI recorded in
February102AQI
Lowest AQI recorded in
September53AQI
202274AQI
Highest AQI recorded in
February95AQI
Lowest AQI recorded in
August28AQI
202175AQI
Highest AQI recorded in
March108AQI
Lowest AQI recorded in
September43AQI
202068AQI
Highest AQI recorded in
December90AQI
Lowest AQI recorded in
July50AQI
Most & Least Polluted Years Over the Last 6 Years
Chonan's annual 2025 AQI (62) shows an average percentage change of -11.3% (improved AQI) compared to previous years: 2020 (68), 2021 (75), 2022 (74), 2023 (72), 2024 (64).