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MPCA Home
> Air Quality Index
Air Quality Index for Minnesota
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The Air Quality Index (AQI) reports daily air quality conditions.
In Minnesota, four pollutants are used to calculate the AQI: ground-level
ozone, sulfur dioxide, carbon monoxide and fine particles (PM2.5).
Not all pollutants are monitored at each location. The pollutant
with the highest value determines the AQI for that hour.
The two pollutants of most concern in Minnesota are ozone and
PM2.5. Ozone, also called smog, is only a problem in warm weather
and so is only monitored from April through September. PM2.5 is
monitored year-round. While the AQI in Minnesota cities rarely
reaches the “unhealthy” or red range, many citizens
are affected by air quality in the orange range, or “unhealthy
for sensitive groups.”
AQI Color Legend:
| Good |
0-50 |
| Moderate |
51-100 |
| Unhealthy for Sensitive Groups |
101-150 |
| Unhealthy |
151-200 |
| Very Unhealthy |
201-300 |
An AQI value from 0 to 50 is good quality, 51
to 100 is moderate quality, 101-150 is unhealthy for sensitive
groups, 151-200 is unhealthy, and 201-300 is very unhealthy.
For more information, see the color-coded
AQI health effects and cautionary statements below.
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Today's Air Quality
(Click on city for details)
AQI Values for Online Sites
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National Air Quality Forecast Maps:
These forecasts are prepared by the U.S. Environmental
Protection Agency's Office of Air Quality Planning and Standards.
Pollen Information:
About
the AQI
The Air Quality Index (AQI) was developed by the U.S. Environmental
Protection Agency (EPA) to provide a simple, uniform way to report daily
air quality conditions.
The AQI in Minnesota is determined by measuring four pollutants: ozone,
sulfur dioxide (SO2), fine particulate matter (PM2.5), and carbon monoxide.
Not all pollutants are measured at each location. The Minnesota Pollution
Control Agency (MPCA) takes hourly measurements of these pollutants
at air quality sites located throughout the state. Ozone levels, which
are only elevated in warm weather, are measured from April through September
in Minnesota.
The AQI translates each pollutant measurement to a common index, with
an index of 100 set to reflect where health effects might be expected
in sensitive populations. An AQI value of 100 generally corresponds
to the National Ambient Air Quality Standard for the pollutant, which
is the level EPA has set to protect public health. The pollutant with
the highest index value is used to determine the overall AQI.
The AQI uses numbers from 0 to 500 to describe the air quality conditions
and their possible effects on human health. Readings of 0-50 are described
as Good, 51-100 as Moderate, 101-150 as Unhealthy for Sensitive Groups,
151-200 Unhealthy, 201-300 Very Unhealthy, and 301 and above Hazardous.
While the AQI in Minnesota cities rarely reaches the “Unhealthy,”
or red, range, many citizens are affected by air quality in the orange
range, or “Unhealthy for Sensitive Groups.”
Call the AQI Hotline for daily air quality forecasts for
the Twin Cities and Rochester at 651-297-1630 (metro) or
1-800-657-3694.
For more information about the the Air Quality Index and information
on air pollution go to the following Environmental Protection Agency's
Air Now Web site from the links below:
For more information on Minnesota's AQI, contact Cassie McMahon, MPCA, at 651-296-7329.
For flyers on what to do when an air pollution alert is called, see:
Pollutant
Description
Ozone (O3)
Ground-level ozone is formed in the atmosphere when nitrogen oxides
and volatile organic compounds react in the presence of heat and sunlight.
Cars, trucks, power plants, and solvents contribute to the formation
of ozone, which is a major component of smog. Ozone can be transported
into an area from sources hundreds of miles upwind. It is irritating
to the eyes, nose, throat and lungs, and it can worsen the symptoms
of asthma. The elderly, children, and people with respiratory illnesses
are most at risk. Ozone can also damage plants, including crops and
trees.
Sulfur
Dioxide (SO2)
Sulfur dioxide is a heavy, pungent, colorless gas formed primarily
by the combustion of coal, oil, and diesel fuels. Elevated levels can
impair breathing, lead to other respiratory symptoms, and at very high
levels aggravate heart disease. People with asthma are most at risk.
Sulfur dioxide also contributes to acid rain, which can damage plants,
lakes and buildings.
Fine Particulate
Matter (PM2.5)
Fine particulate matter is a complex mixture of very small liquid
droplets or solid particles in the air. Major sources are cars, trucks,
construction equipment, coal-fired power plants, wood burning, vegetation
and livestock. These particles can be directly released when coal, gasoline,
diesel fuels and wood are burned. Many fine particles are also formed
in the atmosphere from chemical reactions of nitrogen oxides, sulfur
oxides, organic compounds and ammonia. Fine particulates are associated
with increased hospitalizations and deaths due to respiratory and heart
disease and can worsen the symptoms of asthma. People with respiratory
or heart disease, the elderly and children are the groups most at risk.
Fine particles are also major contributors to reduced visibility (haze).
Carbon
Monoxide (CO)
Carbon monoxide is a colorless, odorless, highly toxic gas emitted
from automobiles, trucks and other gas and diesel-powered equipment.
In small amounts it can impair alertness, cause fatigue and headaches.
In large amounts it can be fatal. People with heart conditions are most
at risk.
Health Effects
| Categories |
Ozone
8-hour |
Carbon
Monoxide
8-hour |
Sulfur
Dioxide
24-hour |
Particulate
Matter
PM-2.5
24-hour |
| Good |
None
|
None
|
None
|
None
|
| Moderate |
Unusually
sensitive individuals may experience respiratory symptoms. |
None
|
None
|
Respiratory symptoms possible in unusually sensitive individuals, possible aggravation of heart or lung disease in people with cardiopulmonary disease and older adults.
|
| Unhealthy
for Sensitive Groups |
Increasing
likelihood of respiratory symptoms and breathing discomfort in
active children and adults and people with respiratory disease,
such as asthma. |
Increasing
likelihood of reduced exercise tolerance due to increased cardiovascular
symptoms, such as chest pain, in people with cardiovascular disease. |
Increasing
likelihood of respiratory symptoms, such as chest tightness and
breathing discomfort, in people with asthma. |
Increasing
likelihood of respiratory symptoms in sensitive individuals, aggravation
of heart or lung disease and premature mortality in persons with
cardiopulmonary disease and the elderly. |
| Unhealthy |
Greater
likelihood of respiratory symptoms and breathing difficulty in active
children and adults and people with respiratory disease, such as
asthma; possible respiratory effects in general population. |
Reduced
exercise tolerance due to increased cardiovascular symptoms, such
as chest pain, in people with cardiovascular disease. |
Increased
respiratory symptoms, such as chest tightness and wheezing, in people
with asthma; possible aggravation of heart or lung disease. |
Increased
aggravation of heart or lung disease and premature mortality in
persons with cardiopulmonary disease and the elderly; increased
respiratory effects in general population. |
| Very
Unhealthy |
Increasingly
severe symptoms and impaired breathing likely in active children
and adults and people with respiratory disease, such as asthma;
increasing likelihood of respiratory effects in general population. |
Significant
aggravation of cardiovascular symptoms, such as chest pain, in people
with cardiovascular disease. |
Significant
increase in respiratory symptoms, such as wheezing and shortness
of breath, in people with asthma; aggravation of heart or lung disease. |
Significant
aggravation of heart or lung disease and premature mortality in
persons with cardiopulmonary disease and the elderly; significant
increase in respiratory effects in general population. |
Cautionary Statements
| Categories |
Ozone
8-hour |
Carbon
Monoxide
8-hour |
Sulfur
Dioxide
24-hour |
Particulate
Matter
PM-2.5
24-hour |
| Good |
None
|
None
|
None
|
None
|
| Moderate |
Unusually
sensitive people should consider limiting prolonged outdoor exertion. |
None
|
None
|
Unusually sensitive people should consider reducing prolonged or heavy exertion
|
| Unhealthy
for Sensitive Groups |
Active
children and adults, and people with respiratory disease, such as
asthma, should limit prolonged outdoor exertion. |
People
with cardiovascular disease, such as angina, should limit heavy
exertion and avoid sources of CO, such as heavy traffic. |
People
with asthma should consider limiting outdoor exertion. |
People
with respiratory or heart disease, the elderly and children should
limit prolonged exertion. |
| Unhealthy |
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. |
People
with cardiovascular disease, such as angina, should limit moderate
exertion and avoid sources of CO, such as heavy traffic. |
Children,
asthmatics, and people with heart or lung disease should limit outdoor
exertion. |
People
with respiratory or heart disease, the elderly and children should
avoid prolonged exertion;everyone else should limit prolonged exertion.
|
| Very
Unhealthy |
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. |
People
with cardiovascular disease, such as angina, should avoid exertion
and sources of CO, such as heavy traffic. |
Children,
asthmatics, and people with heart or lung disease should avoid outdoor
exertion; everyone else should limit outdoor exertion. |
People
with respiratory or heart disease, the elderly and children should
avoid any outdoor activity; everyone else should avoid prolonged
exertion. |
Breakpoints
| Categories |
AQI
Value and Color
|
O3
(ppm)
8-hour
|
CO
(ppm)
8-hour
|
SO2
(ppm)
24-hour
|
PM2.5
(ug/m3)
|
| Good |
0
– 50
Green
|
0.000
- 0.059
|
0.0
- 4.4
|
0.000
- 0.034
|
0.0
– 15.4
|
| Moderate |
51
– 100
Yellow
|
0.060
– 0.075
|
4.5
– 9.4
|
0.035
– 0.144
|
15.5
– 35.4 |
| Unhealthy
for Sensitive Groups |
101
– 150
Orange
|
0.076
– 0.095
|
9.5
– 12.4
|
0.145
– 0.224
|
35.5-55.4 |
| Unhealthy |
151
– 200
Red
|
0.096
– 0.115
|
12.5
– 15.4
|
0.225
– 0.304
|
55.5–140.4 |
| Very
Unhealthy |
201
– 300
Purple
|
0.116
– 0.374
|
15.5
– 30.4
|
0.305
– 0.604
|
140.5
– 210.4 |
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