Nagaoka, Okayama, Okayama, Japan 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
Nagaoka, Okayama, Okayama, Japan
AQI Trends: Highest and Lowest
Same Day Analysis (2nd September ):
On this day, AQI across the 2 years varied significantly: 2025 ranks 2nd highest AQI at 36 of Good air quality, showing improvement over 2024 on the same day.
Download 2024 Annual Data
World Air Quality Report

Day & Night AQI Trend: 3rd Sep - 4th Sep 2025
Nagaoka, Okayama, Okayama, Japan
5 AM3rd Sep 2025
6 PM
4 AM4th Sep 2025
53AQI
30AQI
44AQI
34AQI
In the last 24 hours,
Nagaoka's AQI reached its highest point of 53 at 1 PM during the Day, while the lowest point, 30, was recorded at 10 AM during the Day between 3rd Sep and 4th Sep 2025.
Day & Night AQI Trend : Aug - Sep 2025
Nagaoka, Okayama, Okayama, Japan
30°C27/34°C
31°C27/35°C
29°C26/34°C
28°C24/32°C
25°C23/27°C
24°C24/25°C
25°C25/26°C
25°C24/26°C
28°C25/31°C
29°C26/33°C
28°C26/32°C
28°C25/32°C
29°C26/33°C
29°C25/33°C
29°C26/33°C
29°C26/33°C
29°C25/33°C
29°C26/32°C
29°C26/33°C
29°C26/33°C
29°C26/32°C
29°C26/32°C
28°C25/31°C
28°C25/31°C
29°C26/33°C
30°C26/34°C
30°C26/33°C
29°C26/33°C
29°C26/33°C
28°C25/32°C
--°C/°C
50AQI
42AQI
49AQI
44AQI
2025 Days Vs Air Quality
Nagaoka, Okayama, Okayama, Japan
60%
147
39%
96
0.8%
2
Total number of days with different AQI categories in last 247 days in 2025 (118 days remaining)
Under WHO’s Safe Air Quality Limits: 60%
Health Risk Level:
Moderate
In 2025, 60% of 247 days were within WHO’s safe air quality limits, and 40% exceeded them. The risk of health issues is Moderate, particularly for individuals with respiratory or heart conditions.
Annual Air Quality Insights
Nagaoka, Okayama, Okayama, Japan
AQI levels in 2025
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
38AQI
47AQI
40AQI
33AQI
37AQI
47AQI
34AQI
36AQI
30AQI
28AQI
30AQI
34AQI
37AQI
50AQI
41AQI
39AQI
33AQI
36AQI
45AQI
52AQI
47AQI
68AQI
85AQI
71AQI
49AQI
44AQI
37AQI
39AQI
32AQI
45AQI
67AQI
73AQI
46AQI
56AQI
40AQI
41AQI
33AQI
38AQI
32AQI
31AQI
32AQI
32AQI
44AQI
31AQI
46AQI
30AQI
57AQI
41AQI
40AQI
35AQI
34AQI
31AQI
35AQI
34AQI
35AQI
39AQI
40AQI
69AQI
77AQI
99AQI
101AQI
57AQI
49AQI
35AQI
40AQI
36AQI
42AQI
39AQI
44AQI
43AQI
55AQI
54AQI
48AQI
39AQI
26AQI
38AQI
34AQI
37AQI
49AQI
60AQI
66AQI
72AQI
75AQI
68AQI
60AQI
57AQI
51AQI
51AQI
47AQI
47AQI
46AQI
45AQI
42AQI
47AQI
48AQI
52AQI
50AQI
51AQI
53AQI
53AQI
54AQI
52AQI
49AQI
51AQI
43AQI
50AQI
50AQI
54AQI
53AQI
52AQI
49AQI
50AQI
49AQI
46AQI
56AQI
54AQI
54AQI
52AQI
51AQI
54AQI
53AQI
49AQI
52AQI
47AQI
48AQI
45AQI
47AQI
44AQI
46AQI
45AQI
47AQI
52AQI
55AQI
56AQI
54AQI
53AQI
49AQI
52AQI
54AQI
56AQI
52AQI
46AQI
52AQI
46AQI
42AQI
42AQI
45AQI
45AQI
47AQI
45AQI
46AQI
51AQI
52AQI
47AQI
51AQI
51AQI
53AQI
53AQI
57AQI
53AQI
44AQI
49AQI
53AQI
53AQI
47AQI
47AQI
49AQI
46AQI
51AQI
56AQI
59AQI
56AQI
55AQI
49AQI
46AQI
43AQI
47AQI
57AQI
61AQI
58AQI
60AQI
62AQI
86AQI
95AQI
103AQI
91AQI
78AQI
76AQI
74AQI
84AQI
74AQI
65AQI
60AQI
54AQI
47AQI
52AQI
58AQI
44AQI
45AQI
39AQI
37AQI
35AQI
40AQI
36AQI
35AQI
29AQI
28AQI
26AQI
26AQI
33AQI
39AQI
42AQI
45AQI
44AQI
46AQI
58AQI
50AQI
53AQI
51AQI
51AQI
48AQI
47AQI
37AQI
36AQI
40AQI
44AQI
45AQI
42AQI
42AQI
46AQI
48AQI
48AQI
45AQI
45AQI
47AQI
53AQI
54AQI
55AQI
51AQI
52AQI
54AQI
55AQI
53AQI
42AQI
36AQI
44AQI
42AQI
52AQI
50AQI
49AQI
52AQI
55AQI
48AQI
39AQI
No. of days
202549AQI
Highest AQI recorded in
July55AQI
Lowest AQI recorded in
September39AQI
202442AQI
Highest AQI recorded in
January51AQI
Lowest AQI recorded in
December35AQI
202349AQI
Highest AQI recorded in
December49AQI
Lowest AQI recorded in
November48AQI
202035AQI
Highest AQI recorded in
September35AQI
Lowest AQI recorded in
September35AQI
Most & Least Polluted Years Over the Last 4 Years
Nagaoka's annual 2025 AQI (49) shows an average percentage change of 18.2% (worsened AQI) compared to previous years: 2020 (35), 2023 (49), 2024 (42).