AQI Locations:

Rochester
Brainerd
Duluth
Ely
St Cloud
Twin Cities
Marshall
Detroit Lakes

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.

AQI Site Help

About the AQI

Pollutant description

Health effects

Cautionary Statements

Breakpoints

Map of Air Quality Stations

Air Quality Index for the Duluth Area

The Air Quality Index (AQI) reports daily air-quality conditions in the Duluth area. The pollutant with the highest AQI value determines the air quality.

Current Conditions for the Duluth Area*

Current Conditions for the Duluth Area*
Date	May 25, 2013
Time of this report	07:00 PM
AQI Value	8 - Good (Details/Past Data)
Principal Pollutant	Particulate Matter (PM 2.5)
Health Advisory	No health impacts are expected when air quality is in this range.

*Data is not quality assured at this time.

The AQI is updated hourly between 6:00 a.m. and midnight.

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.

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.

Air quality in the Twin Cities metro area is determined by measuring four pollutants: ozone, sulfur dioxide (SO₂), fine particulate matter (PM_2.5) and carbon monoxide. The Minnesota Pollution Control Agency (MPCA) takes hourly measurements of these pollutants at air quality monitoring sites located throughout the Twin Cities. 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 Moderate, 101-150 Unhealthy for Sensitive Groups, 151-200 Unhealthy, 201-300 Very Unhealthy, and 301 and above Hazardous. The AQI in the Minneapolis/St Paul metro area is rarely in the unhealthy range.

AQI values are reported hourly on the MPCA's Web site. Each weekday, you may also hear a recorded message of the daily AQI for the Twin Cities metro area by dialing 651-297-1630.

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:

Environmental Protection Agency (EPA) AIRNOW Web site
EPA Publication "Air Quality Index - A guide to Air Quality and Your Health"
EPA Publication "Smog - Who Does it Hurt? What you need to know about Ozone and Your Health"
EPA Publication What are the 6 Common Air Pollutants

For more information on Minnesota's AQI, contact Cassie McMahon, MPCA, at 651-757-2564.

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 (PM_2.5)

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 – 12
Moderate	51 – 100 Yellow	0.060 – 0.075	4.5 – 9.4	0.035 – 0.144	12.1 – 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	55.5–150.4
Very Unhealthy	201 – 300 Purple	0.116 – 0.374	15.5 – 30.4	0.305 – 0.604	150.5 – 250.4

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Minnesota Pollution Control Agency, 520 Lafayette Road, St. Paul, MN 55155-4194
Phone: 651-296-6300, 800-657-3864; 24-hour emergency number: 651-649-5451 or 800-422-0798; TTY: 651-282-5332, TTY 24-hour emergency number: 651-297-5353 or 800-627-3529 web2