Tsuruga, Nagano, Nagano, 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
Tsuruga, Nagano, Nagano, Japan
AQI Trends: Highest and Lowest
Same Day Analysis (14th September ):
On this day, AQI across the 3 years varied significantly: 2025 ranks 3rd highest AQI at 40 of Good air quality, showing improvement over 2024 and 2021 on the same day.
Download 2024 Annual Data
World Air Quality Report

Day & Night AQI Trend: 14th Sep - 15th Sep 2025
Tsuruga, Nagano, Nagano, Japan
5 AM14th Sep 2025
6 PM
4 AM15th Sep 2025
AQI
AQI
63AQI
38AQI
In the last 24 hours,
Tsuruga's AQI reached its highest point of 63 at 1 PM during the Night, while the lowest point, 38, was recorded at 8 AM during the Night between 14th Sep and 15th Sep 2025.
Day & Night AQI Trend : Aug - Sep 2025
Tsuruga, Nagano, Nagano, Japan
22°C16/31°C
23°C17/32°C
22°C16/31°C
23°C16/33°C
23°C16/32°C
22°C16/30°C
23°C16/33°C
24°C18/33°C
24°C18/32°C
23°C18/32°C
23°C18/33°C
22°C17/30°C
22°C17/30°C
23°C16/32°C
24°C17/32°C
23°C17/33°C
24°C17/34°C
24°C17/34°C
22°C17/30°C
22°C17/28°C
21°C18/24°C
21°C15/29°C
22°C14/32°C
21°C17/26°C
22°C17/31°C
21°C17/30°C
20°C17/26°C
20°C18/26°C
22°C17/29°C
--°C/°C
--°C/°C
52AQI
45AQI
48AQI
45AQI
2025 Days Vs Air Quality
Tsuruga, Nagano, Nagano, Japan
81%
207
19%
50
Total number of days with different AQI categories in last 257 days in 2025 (108 days remaining)
Under WHO’s Safe Air Quality Limits: 81%
Health Risk Level:
Low
In 2025, 81% of 257 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
Tsuruga, Nagano, Nagano, Japan
AQI levels in 2025
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
33AQI
34AQI
28AQI
27AQI
33AQI
33AQI
32AQI
27AQI
27AQI
26AQI
28AQI
29AQI
33AQI
42AQI
32AQI
35AQI
29AQI
31AQI
38AQI
40AQI
48AQI
45AQI
55AQI
45AQI
41AQI
33AQI
31AQI
33AQI
32AQI
31AQI
28AQI
39AQI
33AQI
37AQI
31AQI
32AQI
30AQI
33AQI
30AQI
29AQI
31AQI
31AQI
37AQI
32AQI
34AQI
30AQI
39AQI
37AQI
34AQI
32AQI
30AQI
31AQI
33AQI
32AQI
32AQI
35AQI
43AQI
50AQI
52AQI
55AQI
53AQI
40AQI
38AQI
30AQI
32AQI
34AQI
43AQI
37AQI
43AQI
37AQI
36AQI
50AQI
43AQI
46AQI
26AQI
25AQI
29AQI
21AQI
29AQI
42AQI
51AQI
62AQI
63AQI
73AQI
76AQI
73AQI
44AQI
41AQI
37AQI
35AQI
28AQI
25AQI
22AQI
23AQI
37AQI
27AQI
37AQI
42AQI
32AQI
45AQI
41AQI
48AQI
27AQI
35AQI
25AQI
26AQI
43AQI
53AQI
62AQI
55AQI
45AQI
53AQI
31AQI
28AQI
36AQI
49AQI
48AQI
50AQI
41AQI
55AQI
50AQI
34AQI
39AQI
35AQI
39AQI
31AQI
30AQI
33AQI
36AQI
26AQI
24AQI
29AQI
42AQI
48AQI
51AQI
55AQI
36AQI
41AQI
42AQI
59AQI
64AQI
52AQI
52AQI
46AQI
29AQI
32AQI
35AQI
33AQI
40AQI
29AQI
24AQI
22AQI
37AQI
29AQI
34AQI
39AQI
46AQI
50AQI
60AQI
61AQI
45AQI
36AQI
47AQI
51AQI
38AQI
29AQI
33AQI
38AQI
46AQI
50AQI
54AQI
56AQI
63AQI
48AQI
47AQI
45AQI
42AQI
50AQI
46AQI
49AQI
53AQI
57AQI
49AQI
51AQI
56AQI
56AQI
56AQI
57AQI
60AQI
62AQI
57AQI
47AQI
48AQI
48AQI
44AQI
38AQI
47AQI
35AQI
37AQI
36AQI
40AQI
42AQI
45AQI
45AQI
49AQI
48AQI
46AQI
43AQI
45AQI
51AQI
51AQI
46AQI
42AQI
45AQI
49AQI
57AQI
53AQI
48AQI
39AQI
38AQI
41AQI
37AQI
35AQI
36AQI
39AQI
44AQI
49AQI
47AQI
45AQI
48AQI
48AQI
50AQI
50AQI
52AQI
51AQI
57AQI
57AQI
57AQI
51AQI
49AQI
53AQI
54AQI
55AQI
50AQI
44AQI
41AQI
34AQI
32AQI
39AQI
36AQI
43AQI
48AQI
49AQI
45AQI
39AQI
42AQI
40AQI
34AQI
35AQI
43AQI
39AQI
39AQI
45AQI
48AQI
48AQI
42AQI
No. of days
202541AQI
Highest AQI recorded in
July48AQI
Lowest AQI recorded in
January34AQI
202436AQI
Highest AQI recorded in
September44AQI
Lowest AQI recorded in
February21AQI
202326AQI
Highest AQI recorded in
December26AQI
Lowest AQI recorded in
November16AQI
202237AQI
Highest AQI recorded in
March43AQI
Lowest AQI recorded in
April32AQI
202134AQI
Highest AQI recorded in
June47AQI
Lowest AQI recorded in
January25AQI
202031AQI
Highest AQI recorded in
August47AQI
Lowest AQI recorded in
December21AQI
Most & Least Polluted Years Over the Last 6 Years
Tsuruga's annual 2025 AQI (41) shows an average percentage change of 28.5% (worsened AQI) compared to previous years: 2020 (31), 2021 (34), 2022 (37), 2023 (26), 2024 (36).