Hanoi, Ha Noi, Vietnam 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+

September Air Quality Analysis
Hanoi, Ha Noi, Vietnam

2021

2022

2023

2024

2025

AQI

Days

Days	2025	2024	2023	2022	2021
Sep. 1	42	36	63		53
Sep. 2	42	36	71	42	42
Sep. 3	41	33	52	55	55
Sep. 4	47	34	48	44	46
Sep. 5	41	35	63	46	24
Sep. 6	41	67	82	59	39
Sep. 7	50	50	79	81	56
Sep. 8	56	46	56	48	41
Sep. 9	48	58	51	41	23
Sep. 10	51	42	63	81	53
Sep. 11	45	47	60	53	54
Sep. 12	42	82	76	47	78
Sep. 13	40	103	54	65	92
Sep. 14	41	130	47	94	50
Sep. 15	44	159	46	58	35
Sep. 16	48	90	76	48	34
Sep. 17	49	84	115	47	32
Sep. 18		81	70	67	33
Sep. 19		107	64	53	35
Sep. 20		98	63	58	60
Sep. 21		78	59	47	81
Sep. 22		63	61	43	58
Sep. 23		83	50	44	59
Sep. 24		131	59	57	56
Sep. 25		155	70	59	32
Sep. 26		163	62	51	41
Sep. 27		129	48	58	45
Sep. 28		78	55	58	61
Sep. 29		64	87	45	70
Sep. 30		63	121	38	55

AQI Trends: Highest and Lowest

Highest AQI recorded on

26th Sep 2024

163AQI

Lowest AQI recorded on

9th Sep 2021

23AQI

Same Day Analysis (17th September ):
On this day, AQI across the 5 years varied significantly: 2025 ranks 3rd highest AQI at 49 of Good air quality, showing improvement over 2024 and 2023 on the same day.

Day & Night AQI Trend: 17th Sep - 18th Sep 2025
Hanoi, Ha Noi, Vietnam

AQI

Day

Night

5 AM17th Sep 2025

6 PM

4 AM18th Sep 2025

Day time

Avg. Highest Time

8AM17th Sep

64AQI

Avg. Lowest Time

1PM17th Sep

37AQI

Night time

Avg. Highest Time

10PM17th Sep

54AQI

Avg. Lowest Time

6PM17th Sep

42AQI

In the last 24 hours,

Hanoi's AQI reached its highest point of 64 at 8 AM during the Day, while the lowest point, 37, was recorded at 1 PM during the Day between 17th Sep and 18th Sep 2025.

Day & Night AQI Trend : Aug - Sep 2025
Hanoi, Ha Noi, Vietnam

AugSep

19th - 20th20th - 21st21st - 22nd22nd - 23rd23rd - 24th24th - 25th25th - 26th26th - 27th27th - 28th28th - 29th29th - 30th30th - 31st31st - 01st01st - 02nd02nd - 03rd03rd - 04th04th - 05th05th - 06th06th - 07th07th - 08th08th - 09th09th - 10th10th - 11th11th - 12th12th - 13th13th - 14th14th - 15th15th - 16th16th - 17th17th - 18th18th

Day

Night

25°C24/26°C

28°C24/33°C

28°C25/31°C

27°C25/31°C

28°C25/33°C

29°C25/34°C

25°C24/29°C

24°C23/25°C

25°C24/28°C

27°C23/32°C

27°C24/32°C

27°C24/31°C

27°C24/30°C

27°C25/31°C

28°C25/33°C

29°C25/34°C

29°C25/33°C

29°C26/35°C

30°C26/35°C

30°C26/36°C

28°C26/32°C

28°C25/31°C

28°C25/33°C

28°C25/32°C

28°C25/33°C

28°C25/31°C

28°C24/33°C

27°C25/31°C

5 AM

11 AM

6 PM

11 PM

4 AM

--°C/°C

Day time

Avg. Highest Time

5 AM - 6 AM

47AQI

2 hours / Day

60 hours / Month

Avg. Lowest Time

3 PM - 5 PM

38AQI

3 hours / Day

90 hours / Month

In the last 30 days, during the daytime, the highest AQI was between 5 AM to 6 AM (Avg. 47), while the lowest AQI was between 3 PM to 5 PM (Avg. 38).

Night time

Avg. Highest Time

12 AM - 11 PM

47AQI

10 hours / Day

300 hours / Month

Avg. Lowest Time

12 AM - 7 PM

47AQI

6 hours / Day

180 hours / Month

In the last 30 days, during the daytime, the highest AQI was between 12 AM to 11 PM (Avg. 47), while the lowest AQI was between 12 AM to 7 PM (Avg. 47).

2025 Days Vs Air Quality
Hanoi, Ha Noi, Vietnam

2025

15%

61%

159

21%

Total number of days with different AQI categories in last 261 days in 2025 (104 days remaining)

Good

38 Days

Moderate

159 Days

Poor

55 Days

Unhealthy

8 Days

Severe

0 Days

Hazardous

0 Days

Under WHO’s Safe Air Quality Limits: 15%

Health Risk Level:

Extreme

In 2025, 15% of 261 days were within WHO’s safe air quality limits. The risk of health issues is Extreme, potentially causing respiratory problems, heart disease, skin issues, and stress, especially for children, the elderly, and those with pre-existing conditions.

Annual Air Quality Insights
Hanoi, Ha Noi, Vietnam

AQI levels in 2025

AQI

PM2.5

PM10

SO2

NO2

Sun.Mon.Tue.Wed.Thu.Fri.Sat.

Jan.

Feb.

Mar.

Apr.

May

Jun.

Jul.

Aug.

Sep.

Oct.

Nov.

Dec.

133AQI

103AQI

97AQI

94AQI

65AQI

59AQI

48AQI

45AQI

No. of days

Jan.Feb.Mar.Apr.MayJun.Jul.Aug.Sep.Oct.Nov.Dec.Total Days

202580AQI

159

Highest AQI recorded in

January

133AQI

Lowest AQI recorded in

September

45AQI

202478AQI

224

Highest AQI recorded in

December

102AQI

Lowest AQI recorded in

August

37AQI

202378AQI

229

Highest AQI recorded in

January

108AQI

Lowest AQI recorded in

July

53AQI

202257AQI

172

120

Highest AQI recorded in

December

91AQI

Lowest AQI recorded in

August

22AQI

202171AQI

122

172

Highest AQI recorded in

January

136AQI

Lowest AQI recorded in

July

41AQI

202074AQI

127

Highest AQI recorded in

April

119AQI

Lowest AQI recorded in

August

49AQI

Most & Least Polluted Years Over the Last 6 Years

Most Polluted Year Recorded

2025(Avg.)

80AQI

Least Polluted Year Recorded

2022(Avg.)

57AQI

Hanoi's annual 2025 AQI (80) shows an average percentage change of 12.7% (worsened AQI) compared to previous years: 2020 (74), 2021 (71), 2022 (57), 2023 (78), 2024 (78).


5 AM	49
6 AM	48
7 AM	57
8 AM	64
9 AM	54
10 AM	58
11 AM	51
12 PM	38
1 PM	37
2 PM	45
3 PM	43
4 PM	42
5 PM	40
6 PM	42
7 PM	44
8 PM	50
9 PM	53
10 PM	54
11 PM	54
12 AM	54
1 AM	50
2 AM	48
3 AM	48
4 AM	48

Hanoi, Ha Noi, Vietnam Historical Air Quality Analysis

September Air Quality AnalysisHanoi, Ha Noi, Vietnam

Day & Night AQI Trend: 17th Sep - 18th Sep 2025Hanoi, Ha Noi, Vietnam

Day & Night AQI Trend : Aug - Sep 2025Hanoi, Ha Noi, Vietnam

2025 Days Vs Air Quality Hanoi, Ha Noi, Vietnam

Annual Air Quality InsightsHanoi, Ha Noi, Vietnam

AQI levels in 2025

No. of days

September Air Quality Analysis
Hanoi, Ha Noi, Vietnam

Day & Night AQI Trend: 17th Sep - 18th Sep 2025
Hanoi, Ha Noi, Vietnam

Day & Night AQI Trend : Aug - Sep 2025
Hanoi, Ha Noi, Vietnam

2025 Days Vs Air Quality
Hanoi, Ha Noi, Vietnam

Annual Air Quality Insights
Hanoi, Ha Noi, Vietnam