Introduction
The air quality in the United States varies greatly by region and state. While some states like North Dakota and South Dakota have relatively low levels of air pollution, other states such as California, New York, and Pennsylvania experience significantly higher levels of air pollution. Generally speaking, parts of the western and northeastern US tend to be more polluted than other regions due to their larger urban populations. Pollutants come from many sources including motor vehicles, power plants, industrial facilities, burning wood or other fuels for cooking and heating, wildfires, volcanic activity, agricultural activities, and natural windblown dust. In 2020 the American Lung Association published its annual State of the Air report which found that unhealthy ozone levels increased across the United States while particle pollution decreased overall. This was attributed to fewer emissions resulting from stay-at-home orders during the COVID-19 pandemic. Factors impacting air quality vary by state due to differences in population density and geography as well as local policies on emissions reduction. In regions with significant manufacturing centers such as Michigan or Ohio or in agricultural areas such as California, additional pollutants are released into the atmosphere that can cause harm to human health. In addition to Environmental Protection Agency emission standards designed to reduce pollutants, there are also a variety of public initiatives in place around the country aiming to improve air quality both now and over time including funding for alternative transportation methods such as electric cars or public bike sharing programs.
| # | State | Good Air Quality Days | Unhealthy Air Quality Days | Moderate Air Quality Days |
|---|---|---|---|---|
| 1 | Hawaii | 99.4% | 0% | 0.6% |
| 2 | Maine | 93.2% | 0.5% | 6.3% |
| 3 | Alaska | 92.3% | 1.3% | 6.4% |
| 4 | Virginia | 91.5% | 0.2% | 8.4% |
| 5 | Vermont | 91.3% | 0.2% | 8.5% |
| 6 | New Hampshire | 91% | 0.5% | 8.5% |
| 7 | Florida | 89.8% | 0% | 10.2% |
| 8 | New York | 88.7% | 0.6% | 10.6% |
| 9 | Washington | 88.7% | 1.6% | 9.7% |
| 10 | Louisiana | 87.9% | 0.2% | 11.9% |
| 11 | Massachusetts | 87.1% | 0.5% | 12.5% |
| 12 | Nebraska | 86.8% | 0.5% | 12.6% |
| 13 | Rhode Island | 86.7% | 0.8% | 12.4% |
| 14 | West Virginia | 86.7% | 0% | 13.2% |
| 15 | North Carolina | 86.3% | 0.1% | 13.7% |
| 16 | Missouri | 86.1% | 0.4% | 13.4% |
| 17 | Alabama | 85.8% | 0.2% | 14% |
| 18 | Mississippi | 85.5% | 0% | 14.5% |
| 19 | Kentucky | 85.2% | 0.2% | 14.6% |
| 20 | South Carolina | 84.9% | 0.1% | 15.1% |
| 21 | Tennessee | 84.5% | 0.3% | 15.2% |
| 22 | Maryland | 84.2% | 0.7% | 15.1% |
| 23 | Connecticut | 83.4% | 2.3% | 14.3% |
| 24 | Minnesota | 83.4% | 1.2% | 15.4% |
| 25 | Arkansas | 83% | 0.2% | 16.8% |
| 26 | Oregon | 83% | 2.9% | 14.1% |
| 27 | New Jersey | 82.3% | 0.8% | 16.9% |
| 28 | Georgia | 82.1% | 0.4% | 17.5% |
| 29 | South Dakota | 82.1% | 1.3% | 16.6% |
| 30 | North Dakota | 81.1% | 3.2% | 15.8% |
| 31 | Indiana | 80.9% | 0.3% | 18.8% |
| 32 | Ohio | 80.9% | 0.3% | 18.8% |
| 33 | Kansas | 80.8% | 0.9% | 18.3% |
| 34 | Montana | 80.8% | 3.3% | 15.9% |
| 35 | Texas | 80.5% | 1% | 18.5% |
| 36 | Delaware | 80.3% | 0.7% | 19% |
| 37 | Michigan | 79.9% | 0.7% | 19.4% |
| 38 | Wisconsin | 79.8% | 0.9% | 19.3% |
| 39 | Pennsylvania | 79.2% | 0.6% | 20.2% |
| 40 | Idaho | 79% | 2.9% | 18.1% |
| 41 | New Mexico | 78.9% | 1.7% | 19.3% |
| 42 | Wyoming | 78.9% | 1.8% | 19.3% |
| 43 | Iowa | 78.3% | 0.4% | 21.3% |
| 44 | Oklahoma | 76.7% | 1.1% | 22.2% |
| 45 | Colorado | 75.4% | 3.7% | 20.9% |
| 46 | Illinois | 75% | 0.8% | 24.3% |
| 47 | Nevada | 72.5% | 4.7% | 22.8% |
| 48 | Utah | 70.2% | 3.2% | 26.6% |
| 49 | District of Columbia | 69% | 2.2% | 28.8% |
| 50 | Arizona | 64.6% | 6.5% | 28.9% |
| 51 | California | 60.6% | 8.4% | 31.1% |
Good Air Quality Days by State
Alabama
Good Air Quality Days
85.8%
Ranked in the US
#17
Unhealthy Air Quality Days
0.2%
Ranked in the US
#7
Moderate Air Quality Days
14%
Ranked in the US
#35
Alaska
Good Air Quality Days
92.3%
Ranked in the US
#3
Unhealthy Air Quality Days
1.3%
Ranked in the US
#37
Moderate Air Quality Days
6.4%
Ranked in the US
#50
Arizona
Good Air Quality Days
64.6%
Ranked in the US
#50
Unhealthy Air Quality Days
6.5%
Ranked in the US
#51
Moderate Air Quality Days
28.9%
Ranked in the US
#2
Arkansas
Good Air Quality Days
83%
Ranked in the US
#25
Unhealthy Air Quality Days
0.2%
Ranked in the US
#8
Moderate Air Quality Days
16.8%
Ranked in the US
#23
California
Good Air Quality Days
60.6%
Ranked in the US
#51
Unhealthy Air Quality Days
8.4%
Ranked in the US
#52
Moderate Air Quality Days
31.1%
Ranked in the US
#1
Colorado
Good Air Quality Days
75.4%
Ranked in the US
#45
Unhealthy Air Quality Days
3.7%
Ranked in the US
#49
Moderate Air Quality Days
20.9%
Ranked in the US
#9
Connecticut
Good Air Quality Days
83.4%
Ranked in the US
#23
Unhealthy Air Quality Days
2.3%
Ranked in the US
#43
Moderate Air Quality Days
14.3%
Ranked in the US
#33
Delaware
Good Air Quality Days
80.3%
Ranked in the US
#36
Unhealthy Air Quality Days
0.7%
Ranked in the US
#25
Moderate Air Quality Days
19%
Ranked in the US
#15
District of Columbia
Good Air Quality Days
69%
Ranked in the US
#49
Unhealthy Air Quality Days
2.2%
Ranked in the US
#42
Moderate Air Quality Days
28.8%
Ranked in the US
#3
Florida
Good Air Quality Days
89.8%
Ranked in the US
#7
Unhealthy Air Quality Days
0%
Ranked in the US
#1
Moderate Air Quality Days
10.2%
Ranked in the US
#45
Georgia
Good Air Quality Days
82.1%
Ranked in the US
#28
Unhealthy Air Quality Days
0.4%
Ranked in the US
#16
Moderate Air Quality Days
17.5%
Ranked in the US
#21
Hawaii
Good Air Quality Days
99.4%
Ranked in the US
#1
Unhealthy Air Quality Days
0%
Ranked in the US
#2
Moderate Air Quality Days
0.6%
Ranked in the US
#52
Idaho
Good Air Quality Days
79%
Ranked in the US
#40
Unhealthy Air Quality Days
2.9%
Ranked in the US
#44
Moderate Air Quality Days
18.1%
Ranked in the US
#20
Illinois
Good Air Quality Days
75%
Ranked in the US
#46
Unhealthy Air Quality Days
0.8%
Ranked in the US
#29
Moderate Air Quality Days
24.3%
Ranked in the US
#5
Indiana
Good Air Quality Days
80.9%
Ranked in the US
#31
Unhealthy Air Quality Days
0.3%
Ranked in the US
#13
Moderate Air Quality Days
18.8%
Ranked in the US
#16
Iowa
Good Air Quality Days
78.3%
Ranked in the US
#43
Unhealthy Air Quality Days
0.4%
Ranked in the US
#17
Moderate Air Quality Days
21.3%
Ranked in the US
#8
Kansas
Good Air Quality Days
80.8%
Ranked in the US
#33
Unhealthy Air Quality Days
0.9%
Ranked in the US
#32
Moderate Air Quality Days
18.3%
Ranked in the US
#19
Kentucky
Good Air Quality Days
85.2%
Ranked in the US
#19
Unhealthy Air Quality Days
0.2%
Ranked in the US
#9
Moderate Air Quality Days
14.6%
Ranked in the US
#31
Louisiana
Good Air Quality Days
87.9%
Ranked in the US
#10
Unhealthy Air Quality Days
0.2%
Ranked in the US
#10
Moderate Air Quality Days
11.9%
Ranked in the US
#43
Maine
Good Air Quality Days
93.2%
Ranked in the US
#2
Unhealthy Air Quality Days
0.5%
Ranked in the US
#19
Moderate Air Quality Days
6.3%
Ranked in the US
#51
Maryland
Good Air Quality Days
84.2%
Ranked in the US
#22
Unhealthy Air Quality Days
0.7%
Ranked in the US
#26
Moderate Air Quality Days
15.1%
Ranked in the US
#29
Massachusetts
Good Air Quality Days
87.1%
Ranked in the US
#11
Unhealthy Air Quality Days
0.5%
Ranked in the US
#20
Moderate Air Quality Days
12.5%
Ranked in the US
#40
Michigan
Good Air Quality Days
79.9%
Ranked in the US
#37
Unhealthy Air Quality Days
0.7%
Ranked in the US
#27
Moderate Air Quality Days
19.4%
Ranked in the US
#11
Minnesota
Good Air Quality Days
83.4%
Ranked in the US
#24
Unhealthy Air Quality Days
1.2%
Ranked in the US
#36
Moderate Air Quality Days
15.4%
Ranked in the US
#27
Mississippi
Good Air Quality Days
85.5%
Ranked in the US
#18
Unhealthy Air Quality Days
0%
Ranked in the US
#3
Moderate Air Quality Days
14.5%
Ranked in the US
#32
Missouri
Good Air Quality Days
86.1%
Ranked in the US
#16
Unhealthy Air Quality Days
0.4%
Ranked in the US
#18
Moderate Air Quality Days
13.4%
Ranked in the US
#37
Montana
Good Air Quality Days
80.8%
Ranked in the US
#34
Unhealthy Air Quality Days
3.3%
Ranked in the US
#48
Moderate Air Quality Days
15.9%
Ranked in the US
#25
Nebraska
Good Air Quality Days
86.8%
Ranked in the US
#12
Unhealthy Air Quality Days
0.5%
Ranked in the US
#21
Moderate Air Quality Days
12.6%
Ranked in the US
#39
Nevada
Good Air Quality Days
72.5%
Ranked in the US
#47
Unhealthy Air Quality Days
4.7%
Ranked in the US
#50
Moderate Air Quality Days
22.8%
Ranked in the US
#6
New Hampshire
Good Air Quality Days
91%
Ranked in the US
#6
Unhealthy Air Quality Days
0.5%
Ranked in the US
#22
Moderate Air Quality Days
8.5%
Ranked in the US
#47
New Jersey
Good Air Quality Days
82.3%
Ranked in the US
#27
Unhealthy Air Quality Days
0.8%
Ranked in the US
#30
Moderate Air Quality Days
16.9%
Ranked in the US
#22
New Mexico
Good Air Quality Days
78.9%
Ranked in the US
#41
Unhealthy Air Quality Days
1.7%
Ranked in the US
#40
Moderate Air Quality Days
19.3%
Ranked in the US
#12
New York
Good Air Quality Days
88.7%
Ranked in the US
#8
Unhealthy Air Quality Days
0.6%
Ranked in the US
#23
Moderate Air Quality Days
10.6%
Ranked in the US
#44
North Carolina
Good Air Quality Days
86.3%
Ranked in the US
#15
Unhealthy Air Quality Days
0.1%
Ranked in the US
#5
Moderate Air Quality Days
13.7%
Ranked in the US
#36
North Dakota
Good Air Quality Days
81.1%
Ranked in the US
#30
Unhealthy Air Quality Days
3.2%
Ranked in the US
#46
Moderate Air Quality Days
15.8%
Ranked in the US
#26
Ohio
Good Air Quality Days
80.9%
Ranked in the US
#32
Unhealthy Air Quality Days
0.3%
Ranked in the US
#14
Moderate Air Quality Days
18.8%
Ranked in the US
#17
Oklahoma
Good Air Quality Days
76.7%
Ranked in the US
#44
Unhealthy Air Quality Days
1.1%
Ranked in the US
#35
Moderate Air Quality Days
22.2%
Ranked in the US
#7
Oregon
Good Air Quality Days
83%
Ranked in the US
#26
Unhealthy Air Quality Days
2.9%
Ranked in the US
#45
Moderate Air Quality Days
14.1%
Ranked in the US
#34
Pennsylvania
Good Air Quality Days
79.2%
Ranked in the US
#39
Unhealthy Air Quality Days
0.6%
Ranked in the US
#24
Moderate Air Quality Days
20.2%
Ranked in the US
#10
Rhode Island
Good Air Quality Days
86.7%
Ranked in the US
#13
Unhealthy Air Quality Days
0.8%
Ranked in the US
#31
Moderate Air Quality Days
12.4%
Ranked in the US
#41
South Carolina
Good Air Quality Days
84.9%
Ranked in the US
#20
Unhealthy Air Quality Days
0.1%
Ranked in the US
#6
Moderate Air Quality Days
15.1%
Ranked in the US
#30
South Dakota
Good Air Quality Days
82.1%
Ranked in the US
#29
Unhealthy Air Quality Days
1.3%
Ranked in the US
#38
Moderate Air Quality Days
16.6%
Ranked in the US
#24
Tennessee
Good Air Quality Days
84.5%
Ranked in the US
#21
Unhealthy Air Quality Days
0.3%
Ranked in the US
#15
Moderate Air Quality Days
15.2%
Ranked in the US
#28
Texas
Good Air Quality Days
80.5%
Ranked in the US
#35
Unhealthy Air Quality Days
1%
Ranked in the US
#34
Moderate Air Quality Days
18.5%
Ranked in the US
#18
Utah
Good Air Quality Days
70.2%
Ranked in the US
#48
Unhealthy Air Quality Days
3.2%
Ranked in the US
#47
Moderate Air Quality Days
26.6%
Ranked in the US
#4
Vermont
Good Air Quality Days
91.3%
Ranked in the US
#5
Unhealthy Air Quality Days
0.2%
Ranked in the US
#11
Moderate Air Quality Days
8.5%
Ranked in the US
#48
Virginia
Good Air Quality Days
91.5%
Ranked in the US
#4
Unhealthy Air Quality Days
0.2%
Ranked in the US
#12
Moderate Air Quality Days
8.4%
Ranked in the US
#49
Washington
Good Air Quality Days
88.7%
Ranked in the US
#9
Unhealthy Air Quality Days
1.6%
Ranked in the US
#39
Moderate Air Quality Days
9.7%
Ranked in the US
#46
West Virginia
Good Air Quality Days
86.7%
Ranked in the US
#14
Unhealthy Air Quality Days
0%
Ranked in the US
#4
Moderate Air Quality Days
13.2%
Ranked in the US
#38
Wisconsin
Good Air Quality Days
79.8%
Ranked in the US
#38
Unhealthy Air Quality Days
0.9%
Ranked in the US
#33
Moderate Air Quality Days
19.3%
Ranked in the US
#13
Wyoming
Good Air Quality Days
78.9%
Ranked in the US
#42
Unhealthy Air Quality Days
1.8%
Ranked in the US
#41
Moderate Air Quality Days
19.3%
Ranked in the US
#14