Michigan’s Departments of Natural Resources and Environmental Quality report on the state of the environment

Possessing more than 3,000 miles of Great Lakes shoreline, 11,000 inland lakes, abundant forests and diverse wildlife, Michiganders have reason to pride themselves on their surroundings. Protecting the state's natural resources is of great concern for many Michigan residents.

Fortunately, Michigan is doing relatively well on the environmental front, according to the 2008 first triennial report on the state's environment. Published by the Michigan departments of Natural Resources and Environmental Quality, the report examines indicators that reflect biological, chemical and physical aspects of the environment.


Michigan has some of the most diverse forests in the United States, with more than 75 different tree species. Between 1980 and 1993, maple, birch and beech trees have increased by nearly 1 million acres, and are expected to increase based on existing conditions. The report concludes that standing timber volumes tripled since the 1950s, which means that Michigan is regaining much of the mature forest lost from fires and logging in the 1800s and early 1900s. Furthermore, the report states: "This expanding volume also indicates that more growth has been continuously added to the forest than what has been removed or died through natural causes. Annual growth has steadily increased over the past 50 years."


According to the report, water levels in the Great Lakes Basin normally fluctuate between 12 inches to 24 inches in a single year. By this standard, water levels remained relatively steady.


The population of wolves in the Upper Peninsula has shown a steady growth since 1989, and from 1994 to 2007 the population increased at an average annual rate of 19 percent, which the report claims "is a positive indicator of ecosystem health." Similarly, the bear population has shown a general increase.


Over the last 25 years, grassland species of birds and transitional species have declined in numbers in favor of more generalist species such as the house finch, northern cardinal, house wren and eastern bluebird, all of which have increased significantly in population. This shift has been attributed to changing habitat conditions, including human activity and the continued maturing of Michigan's forests.

The bald eagle population is a success story in Michigan. From just 50 nests in 1961, 2007 yielded a record number of 526 nests, of which 67 percent produced young, up from 42 percent in 1961. Because the bald eagle is at the top of its food chain, its population is also a good indicator for monitoring changes in levels of contaminants in the environment, such as PCBs (polychlorinated biphenyls) and mercury. In general, the levels of PCBs in the blood of bald eagles were dramatically lower in the 1999-2004 period compared to a decade ago for both the Upper and the Lower Peninsulas. This is in spite of the fact that Michigan has more PCB-contaminated hot spots than any other Great Lakes state, an issue that is being addressed with both federal and state funds.[1]


The population of walleye fluctuates heavily since their presence is strongly related to annual variation in reproductive success. In the late 1970s and early 1980s, their presence was low, after which it peaked in 1989. From 2000 to 2003, their abundance declined to the lowest level observed since 1978, but rebounded in 2004 to the highest level in a decade and has since declined again.

Lake trout populations, on the other hand, are nearly rehabilitated to pre-1940s levels in all areas of Lake Superior except Whitefish Bay. Lake trout populations decreased significantly in the 1940s and 1950s due to commercial over-fishing and parasitism by sea lamprey. Successful programs to restock lake trout populations and control sea lamprey in the 1970s and 1980s sparked a rebound in trout populations, which is considered a positive indicator of the overall health of Michigan's Great Lakes ecosystem.

Since the 1970s, efforts to control pollution have resulted in a significant reduction of contaminants. PCBs in lake trout from the Great Lakes have decreased dramatically.

The potential incursion of Asian carp into the Great Lakes is perhaps the biggest threat to the Great Lakes ecosystem.


Currently, 46 exotic plant and animal species are known to have invaded the Great Lakes Basin. One of the most serious of these threats is the emerald ash borer, native to Asia. It has destroyed millions of ash trees across the Lower Peninsula. Efforts to stop the spread of and eradicate the pest are underway, from implementing quarantines and an inspection station at the Mackinac Bridge to forming the Emerald Ash Borer Task Force, which has begun using an insecticide that kills all of the borers when injected through the bark at the base of ash trees.


The air quality in Michigan has improved significantly over the last 35 years. Six criteria pollutants are routinely monitored: carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter and sulfur dioxide. In 2008, all areas of Michigan were in compliance with the EPA's criteria pollutant standards except for ozone and particulate matter less than 2.5 micrometers in diameter, for which the EPA implemented new standards in 2008.

Carbon Monoxide

Michigan's on-road motor vehicle sources account for 69 percent of the state's carbon monoxide emissions, whereas non-road vehicle sources, such as aircraft, marine vessels and railroads, account for 28 percent. Only 2 percent of emissions come from Michigan's industries. There has been a 50 percent decrease in the average carbon monoxide levels every 10 years since 1984, even though the number of vehicle miles driven has increased.


Currently, smelters and battery plants are the major sources of lead worldwide. Since the 1970s, lead levels in gasoline have been controlled, and since then, concentrations of lead in the air have decreased steadily. In the Detroit area in 2006, the average air quality concentration for lead was 98 percent lower than the high in 1983. Average quarterly lead levels across Michigan are about 50 times below the air quality standard.[2]

Nitrogen Dioxide

Nitrogen dioxide levels in Michigan have remained near the 0.02 parts per million level since 1992, less than half of the amount deemed unsafe by the federal government.[3]


Ozone occurring naturally between 10 and 30 miles above the Earth's surface forms a protective layer against harmful solar rays. In the Earth's lower atmosphere, however, ground-level ozone is a pollutant formed when solar activity initiates a chemical reaction with air pollutants. This usually occurs during warm summer months from reactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs). Within Michigan, 63 percent of the ozone-producing pollutants are emitted by vehicles, whereas the remaining 37 percent come from combustion of fuels, chemical and petroleum manufacturing and natural vegetation such as terpene emitting from resin. In July 2005, the EPA designated 25 Michigan counties as being in "non-attainment" with a new, more stringent ozone standard called the eight-hour standard. This standard was updated in March 2008.[4] Currently, 30 counties are in non-attainment under the new standard.

Particulate Matter

Particulate matter is a broad classification for material that consists of solid particles, fine liquid droplets or condensed liquids absorbed into solid particles. Particulates with a diameter of less than 10 micrometers are referred to as PM10, whereas very fine particles, equal to or less than 2.5 micrometers in diameter, are referred to as PM2.5.

Michigan is in attainment with the PM10 standards5; often well below at most locations. Seven counties in Michigan are in nonattainment with the PM2.[5] standards,[6] which are new since 2006.

Sulfur Dioxide

Sulfur dioxide often comes from coal-burning power plants. Levels of sulfur dioxide have fallen to one-fourth of the annual standard[7] since 1991.

Greenhouse Gas Emissions
and Air Toxics Release

The report states that total greenhouse gas emissions in Michigan increased 9 percent in 2002 over the 1990 emissions baseline.[8] Conversely, the Air Toxics Chemical Release Inventory reported a decrease of 8 percent from 2005 to 2006, which the authors stress does not indicate either an upward or downward trend, since many levels are self-reported. These may be estimates rather than actual measurements, and do not include all industries active in the state. 

[1] 'Teams targeting poison in the River Raisin' by Tina Lam, Detroit Free Press, July 2, 2009.

[2] The air quality standard for lead is 1.5 micrograms per cubic meter.

[3] EPA National Ambient Air Quality Standards list 0.053 ppm as the average 24-hour limit for NO2 in outdoor air.

[4] The original standard was based on concentrations exceeding 0.12 parts per million during one hour. The stricter standard from 2005 is based on concentrations exceeding 0.08 ppm over eight hours. The newest standard from March 2008 is based on concentrations exceeding 0.075 ppm over the course of eight hours.

[5] The PM10 standard is 150 micrograms per cubic meter over the course of 24 hours.

[6] The PM2.5 standard is 35 micrograms per cubic meter over the course of 24 hours.

[7] The annual standard for sulfur dioxide is 0.03 ppm.

[8] Total greenhouse gas emissions in Michigan during 2002 amounted to 62.59 million metric tons carbon equivalent (MMTCE) in comparison to the 1990 baseline of 57.42 MMTCE.