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Air Quality Index

Air Quality

AQI

Health Impacts

Good

0-50

No health impacts are expected when air quality is in this range.

Moderate

51-100

Unusually sensitive people should consider limiting prolonged outdoor exertion.

Unhealthy for
Sensitive Groups

101-150

Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion.

Unhealthy

151-200

Active children and adults and people with respiratory disease such as asthma, should avoid prolonged outdoor exertion: everyone else, especially children, should limit prolonged outdoor exertion.

Very Unhealthy

201-300

Active children and adults and people with respiratory disease, such as asthma, should avoid all outdoor exertion; everyone else, especially children, should limit outdoor exertion.

Hazardous (Alert)

301-500

Active children and adults, and people with respiratory disease, such as asthma, should avoid all outdoor exertion, everyone else, especially children, should limit outdoor exertion.


At the request of the public, environmental agencies had for many years tried to express the quality of the air we breathe in a fashion that could be easily understood. Early on, there were numerous indices utilized across the country. These indices were, in many cases, suited to local environmental concerns, without regards to the comparability from region to region. This led to confusion when the citizens traveled around the country. To alleviate this confusion, the Environmental Protection Agency (EPA) developed the uniform Pollutant Standard Index (PSI) and subsequently the Air Quality Index (AQI), to be used by all agencies across the country.

The AQI is an index for reporting daily air quality. It tells you how clean or polluted your air is, and what associated health effects might be a concern for you. The AQI focuses on health effects you may experience within a few hours or days after breathing polluted air. EPA calculates the AQI for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide. For each of these pollutants, EPA has established national air quality standards to protect public health. Ground-level ozone and airborne particles are the two pollutants that pose the greatest threat to human health in this country.

Each of the pollutants measured is compared to a table of concentration values to determine its sub-index AQI. When all of the sub-indices have been determined, the highest value sub-index is reported as the AQI. The index provides general information to the public about air quality and associated health effects.

2019 AIR QUALITY INDEX SUMMARY

MONTH

GOOD DAYS

MODERATE DAYS

UNHEALTHY FOR SENSITIVE GROUP DAYS

UNHEALTHY DAYS

JANUARY

27
4
00

FEBRUARY

0​000

MARCH

0
0
00

APRIL

0
0
00

MAY

0
0
00

JUNE

0
0
00

JULY

0
0
00

AUGUST

0
0
00

SEPTEMBER

0
0
00

OCTOBER

0
0
00

NOVEMBER

0
0
00

DECEMBER

0
0
00

TOTAL

27
4
00

PERCENT

87.10%12.90%0%0%

2018 AIR QUALITY INDEX SUMMARY

MONTH

GOOD DAYS

MODERATE DAYS

UNHEALTHY FOR SENSITIVE GROUP DAYS

UNHEALTHY DAYS

JANUARY

29 2 0 0

FEBRUARY

28​ 0 0 0

MARCH

13 18 0 0

APRIL

15 15 0 0

MAY

29 2 0 0

JUNE

25 5 0 0

JULY

13 18 0 0

AUGUST

27 4
0 0

SEPTEMBER

27 3
0 0

OCTOBER

30 1 0 0

NOVEMBER

28 2 0 0

DECEMBER

29 2 0 0

TOTAL

293 72 0 0

PERCENT

80.27% 19.73% 0% 0%

2017 AIR QUALITY INDEX SUMMARY

MONTH

GOOD DAYS

MODERATE DAYS

UNHEALTHY FOR SENSITIVE GROUP DAYS

UNHEALTHY DAYS

JANUARY

26 5 0 0

FEBRUARY

16 12 0 0

MARCH

26 4 1 0

APRIL

17 13 0 0

MAY

13​ 14 4 0

JUNE

29 1 0 0

JULY

28 3 0 0

AUGUST

27 4 0 0

SEPTEMBER

24 6 0 0

OCTOBER

26 5 0 0

NOVEMBER

29 1 0 0

DECEMBER

22 9 0 0

TOTAL

283 77 5 0

PERCENT

77.53% 21.10% 1.37% 0%

2016 AIR QUALITY INDEX SUMMARY

MONTH

GOOD DAYS

MODERATE DAYS

UNHEALTHY FOR SENSITIVE GROUP DAYS

UNHEALTHY DAYS

JANUARY

30 1 0 0

FEBRUARY

26 3 0 0

MARCH

30​​ 1 0 0

APRIL

24 6 0 0

MAY

17 14 0 0

JUNE

30 0 0 0

JULY

31 0 0 0

AUGUST

22 0 0 0

SEPTEMBER

26 4 0 0

OCTOBER

29 2 0 0

NOVEMBER

20 10 0 0

DECEMBER

26 5 0 0

TOTAL

301 65 0 0

PERCENT

82.24% 17.76% 0% 0%

AQI incorporates pollutants Ozone, Fine Particulate Matter and Carbon Monoxide.

Air Quality Index Summary Archive: 2001-2011

*About the Data-The air quality data used in these maps and to generate forecasts are collected using either federal reference or equivalent monitoring techniques or techniques approved by the state, local or tribal monitoring agencies. Since the information needed to make maps must be as "real-time" as possible, the data are displayed as soon as practical after the end of each hour. Although some preliminary data quality assessments are performed, the data as such are not fully verified and validated through the quality assurance procedures monitoring organizations use to officially submit and certify data on the EPA AQS(Air Quality System). Therefore, data are used on the AIRNow Web site only for the purpose of reporting the AQI. Information on the AIRNow web site is not used to formulate or support regulation, guidance or any other Agency decision or position.

Source: AirNow​​​​​