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Air Quality Index for the Rochester Area
The Air Quality Index (AQI) reports daily air-quality conditions in the Rochester area. The pollutant with the highest AQI value determines the air quality.
Current Conditions for the Rochester Area*
*Data is not quality assured at this time.
The AQI is updated hourly between 6:00 a.m. and midnight.
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.
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 (PM2.5) 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:
For more information on Minnesota's AQI, contact Cassie McMahon, MPCA, at 651-757-2564.
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 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.
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