Chester, Pennsylvania, United States 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
Chester, Pennsylvania, United States
AQI Trends: Highest and Lowest
Same Day Analysis (23rd August ):
On this day, AQI across the 5 years varied significantly: 2025 ranks 4th highest AQI at 31 of Good air quality, showing improvement over 2024, 2023 and 2021 on the same day.
Download 2024 Annual Data
World Air Quality Report

Day & Night AQI Trend: 23rd Aug - 24th Aug 2025
Chester, Pennsylvania, United States
6 AM23rd Aug 2025
8 PM
5 AM24th Aug 2025
32AQI
27AQI
34AQI
27AQI
In the last 24 hours,
Chester's AQI reached its highest point of 34 at 1 AM during the Night, while the lowest point, 27, was recorded at 5 AM during the Night between 23rd Aug and 24th Aug 2025.
Day & Night AQI Trend : Jul - Aug 2025
Chester, Pennsylvania, United States
--°C/°C
28°C24/32°C
26°C22/30°C
29°C23/34°C
30°C23/37°C
30°C23/37°C
28°C20/37°C
21°C18/24°C
23°C17/28°C
24°C16/31°C
25°C16/34°C
25°C18/32°C
24°C22/27°C
24°C20/29°C
23°C17/29°C
24°C16/32°C
24°C17/33°C
25°C19/33°C
26°C21/32°C
27°C23/32°C
28°C23/31°C
29°C23/33°C
28°C23/35°C
27°C21/35°C
22°C20/22°C
22°C19/25°C
22°C20/25°C
20°C17/23°C
23°C16/32°C
23°C15/31°C
23°C16/31°C
41AQI
41AQI
40AQI
39AQI
2025 Days Vs Air Quality
Chester, Pennsylvania, United States
86%
201
14%
34
Total number of days with different AQI categories in last 237 days in 2025 (128 days remaining)
Under WHO’s Safe Air Quality Limits: 86%
Health Risk Level:
Low
In 2025, 86% of 237 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
Chester, Pennsylvania, United States
AQI levels in 2025
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
28AQI
21AQI
33AQI
23AQI
35AQI
39AQI
22AQI
27AQI
29AQI
29AQI
45AQI
57AQI
48AQI
26AQI
26AQI
43AQI
50AQI
46AQI
46AQI
26AQI
34AQI
53AQI
71AQI
68AQI
62AQI
51AQI
46AQI
38AQI
32AQI
27AQI
43AQI
31AQI
24AQI
43AQI
36AQI
26AQI
32AQI
33AQI
34AQI
34AQI
32AQI
39AQI
54AQI
27AQI
29AQI
31AQI
27AQI
29AQI
27AQI
24AQI
26AQI
26AQI
39AQI
51AQI
55AQI
42AQI
45AQI
45AQI
30AQI
32AQI
29AQI
30AQI
36AQI
29AQI
24AQI
31AQI
30AQI
30AQI
31AQI
36AQI
29AQI
40AQI
47AQI
29AQI
30AQI
21AQI
18AQI
31AQI
27AQI
18AQI
23AQI
18AQI
32AQI
30AQI
28AQI
26AQI
39AQI
60AQI
60AQI
33AQI
19AQI
22AQI
34AQI
28AQI
29AQI
36AQI
25AQI
26AQI
23AQI
25AQI
36AQI
15AQI
20AQI
32AQI
39AQI
21AQI
28AQI
35AQI
53AQI
33AQI
25AQI
41AQI
29AQI
56AQI
31AQI
33AQI
16AQI
18AQI
33AQI
38AQI
29AQI
47AQI
45AQI
28AQI
28AQI
26AQI
20AQI
33AQI
25AQI
23AQI
37AQI
41AQI
25AQI
34AQI
32AQI
36AQI
32AQI
21AQI
23AQI
17AQI
21AQI
22AQI
18AQI
15AQI
16AQI
19AQI
27AQI
26AQI
19AQI
33AQI
34AQI
20AQI
25AQI
31AQI
45AQI
49AQI
52AQI
37AQI
27AQI
27AQI
35AQI
55AQI
63AQI
73AQI
77AQI
40AQI
39AQI
35AQI
25AQI
27AQI
27AQI
43AQI
47AQI
54AQI
56AQI
56AQI
43AQI
44AQI
35AQI
42AQI
41AQI
31AQI
29AQI
46AQI
51AQI
67AQI
56AQI
35AQI
35AQI
35AQI
37AQI
34AQI
28AQI
22AQI
24AQI
22AQI
28AQI
26AQI
24AQI
26AQI
29AQI
35AQI
51AQI
41AQI
39AQI
46AQI
36AQI
79AQI
42AQI
51AQI
55AQI
51AQI
39AQI
49AQI
50AQI
62AQI
79AQI
75AQI
54AQI
34AQI
33AQI
33AQI
42AQI
36AQI
27AQI
27AQI
44AQI
48AQI
52AQI
34AQI
22AQI
20AQI
16AQI
25AQI
31AQI
39AQI
35AQI
32AQI
30AQI
27AQI
42AQI
39AQI
41AQI
No. of days
202535AQI
Highest AQI recorded in
June42AQI
Lowest AQI recorded in
May27AQI
202435AQI
Highest AQI recorded in
July39AQI
Lowest AQI recorded in
November29AQI
202343AQI
Highest AQI recorded in
June75AQI
Lowest AQI recorded in
October35AQI
202240AQI
Highest AQI recorded in
February50AQI
Lowest AQI recorded in
September33AQI
202142AQI
Highest AQI recorded in
July53AQI
Lowest AQI recorded in
September35AQI
202039AQI
Highest AQI recorded in
March46AQI
Lowest AQI recorded in
September32AQI
Most & Least Polluted Years Over the Last 6 Years
Chester's annual 2025 AQI (35) shows an average percentage change of -10.07% (improved AQI) compared to previous years: 2020 (39), 2021 (42), 2022 (40), 2023 (43), 2024 (35).