Indicator : Air pollutants

Rationale: Air pollutants can harm human health and the environment. Air pollution imposes environmental costs through such things as acid rain and toxic exposure for aquatic life and economic costs mainly in the form of public health expenditures and regulatory costs.

Year 1990 154 1991 145 1992 147 1993 158 1994 157 1995 161 1996 157 1997 164 1998 159 1999 189 2000 190

Data source: U.S. Environmental Protection Agency

Year 1990 426 1991 418 1992 425 1993 452 1994 458 1995 477 1996 490 1997 510 1998 499 1999 538 2000 533

Data source: U.S. Environmental Protection Agency

Year 1990 1,990 1991 1,951 1992 1,869 1993 1,806 1994 1,782 1995 1,660 1996 1,794 1997 1,790 1998 1,851 1999 2,044 2000 2,105

Data source: U.S. Environmental Protection Agency

About this indicator: Sulfur dioxide and nitrogen oxide emissions have risen gradually since 1990. Carbon monoxide emissions fell and then increased again starting in 1996, ending the decade with a slight net increase. These trends cover all sources of the three pollutants, including motor vehicles and stationary sources like factories and businesses.

Total emissions of sulfur dioxide rose about 23 percent, from 154 thousand tons in 1990 to 190 thousand tons in 2000. Monitored levels are below the legal limit and are unlikely to exceed it unless sulfur emissions from coal-burning power plants increase dramatically. Increased sulfur emissions will reduce visibility and may hasten acidification in Minnesota's lakes.

Nitrogen oxide emissions increased about 26 percent, from 426 thousand tons to 533 thousand tons. The increase is likely due to several factors: more people driving more miles per person; growth in energy use and therefore an increase in emissions from power plants; and increased emissions from taconite mining (part of which may reflect more accurate measurement). Although nitrogen oxide emissions may continue to rise because of increased travel and fuel use, it is unlikely that these increases will violate the legal standard. Nitrogen oxides contribute to the formation of ozone and smog on hot summer days.

As with both sulfur dioxide and nitrogen oxides, emissions of carbon monoxide showed a net increase for the decade, from 1,990 thousand tons in 1990 to 2,105 thousand tons by 2000. This net increase of three percent is likely due to increased auto travel, which appears to be outpacing any improvements in vehicle emissions or fuel efficiency. Carbon monoxide is a colorless, odorless, highly toxic gas emitted from automobiles. In small amounts it can impair alertness, cause fatigue and headaches. In large amounts it can kill. People with heart conditions and respiratory ailments are especially susceptible.

For comparison: In sulfur dioxide emissions, Minnesota ranks 28th among the states. National emissions dropped 24 percent between 1991 and 2000. While Minnesota's are increasing. In nitrogen oxide emissions, Minnesota ranks 18th Emissions rose three percent nationally between 1991 and 2000, compared to 26 percent in Minnesota.

Minnesota ranks 20th in carbon monoxide emissions. Monitored levels of carbon monoxide have dropped five percent across the country despite significant growth in vehicle miles traveled.

Things to think about: According to research by the University of Minnesota's Center for Transportation Studies, health care and other costs from air pollution emitted by transportation sources alone in the Twin Cities are estimated at $1 billion per year. This estimate includes monetary and nonmonetary costs to individuals, businesses and governments and covers such things as road construction and maintenance, travel time and the costs of owning and operating vehicles. External costs such as congestion, crashes, air pollution, and petroleum consumption accounted for seven percent of the total estimate.

The Minnesota Pollution Control Agency's regulation of large industrial sources of air pollution has contributed to large improvements in air quality in the last two decades. However, hundreds of chemicals, including most toxic chemicals and greenhouse gases, such as carbon dioxide, remain unregulated and pose significant challenges for Minnesotans' long-term health. Since many of these pollutants come from cars, trucks, buses, airplanes and power plants, protection of air quality involves reducing fuel and energy consumption, adopting cleaner fuels and shifting to other technologies that reduce air pollution, such as fuel cells.

Technical notes: Sulfur dioxide, nitrogen oxides and carbon monoxide are three of six primary pollutants (called criteria pollutants) regulated under the federal Clean Air Act. Differences from the numbers reported in Minnesota Milestones 1998 reflect the U.S. Environmental Protection Agency's policy of revising historical data for accuracy and consistency.

Sources:

• Minnesota Pollution Control Agency, www.pca.state.mn.us
• Minnesota Pollution Control Agency, Air Quality in Minnesota: Problems and Approaches, January 2001, www.pca.state.mn.us/hot/legislature/reports/2001/aq-report-na.pdf
• U.S. Environmental Protection Agency, www.epa.gov/oar
• University of Minnesota, Center for Transportation Studies, The Full Cost of Transportation in the Twin Cities Region, August 7, 2000 www.cts.umn.edu/trg/research/rpt5abs.html

Related indicators:

• Energy efficiency of the economy
• Freeway congestion
• Energy use per person
• Renewable energy sources
• Vehicle miles
• Urban air pollution
• Water quality in lakes and rivers
• Nitrate in ground water
• Changes in land use

Other related indicators:

• Energy use by fuel type (Minnesota Department of Commerce, www.commerce.state.mn.us/pages/EnergyMain.htm)
• Estimated annual carbon dioxide emissions (Minnesota Pollution Control Agency, www.pca.state.mn.us)
• Amount of solid waste by disposal method, such as recycled, composted and incinerated: (Minnesota Office of Environmental Assistance, www.moea.state.mn.us)