Some Facts on Automobiles and the Environment
We were asked a while ago if we could provide some information on the impact of automobiles on the environment. Here's what we came up with
Automobiles have a major impact upon the environment. As noted in a fact sheet from the US EPA, "driving a private car is probably a typical citizen's most 'polluting' daily activity".
Each year, the United States produces about 10% of the world's petroleum but consumes about 26% of the world's total production. Cars and light trucks are the single largest users of petroleum, consuming about 43% of the total. Overall, cars and light trucks consume about 16% of the total energy used in the U.S.
Although great strides have been made at reducing air pollution from automobile exhaust over the past 30 years, on-road motor vehicles still account for a significant proportion of air pollution:
|Air Pollutant||Proportion from On-road Motor Vehicles||Note|
|Oxides of Nitrogen (NOx)||34%||precursor to ground-level ozone (smog), which damages the respiratory system and injures plants|
|Volatile Organic Compounds (VOC)||34%||precursor to ground-level ozone (smog), which damages the respiratory system and injures plants|
|Carbon Monoxide (CO)||51%||contributes to smog production; poisonous in high concentrations|
|Particulate Matter (PM10)||10%||does not include dust from paved and unpaved roads, which are the major source of particulate matter pollution (50% of the total)|
|Carbon Dioxide (CO2)||33%||thought to be primary contributor to global warming|
There are a number of ways automobile use results in water pollution:
- Runoff of oil, dirt, brake dust, deposited vehicle exhaust, road particles, automotive fluids, and deicing chemicals from roadways and parking lots. The effect of this is difficult to quantify, but a 1996 survey of 693,905 river miles estimated that urban runoff was the leading source of impairment for 13% of the river miles that were impaired. One EPA researcher estimated the amount of oil and grease runoff from roads surfaces to be in the hundreds of thousands of tons per year.
- Leaking underground fuel storage tanks. As of 1998, there were approx. 892,000 underground storage tanks in the US, mostly in gasoline filling stations. A cumulative total of 1.2 million tanks had been closed, with confirmed releases (leaks) from 371,000 such tanks.
- Improperly disposed of waste fluids, e.g. used motor oil. One quart of motor oil can contaminate a million gallons of fresh water. The US EPA estimates 13.4% of used motor oil is illegally dumped, while another 10.1% is landfilled.
Car and truck noise has become perhaps the primary source of noise pollution in urban environments. A Federal Highway Administration brochure states that a typical pickup truck going by at 50 mph is four times as loud as an air conditioner an eight times as loud as a refrigerator. The Organization for Economic Cooperation and Development (OECD) estimated in 1980 that 37 percent of the US population was exposed to "annoying" levels of highway noise (greater than 55 decibels), while 7% was exposed to levels that made conversation difficult (> 65 dB).
Cars require a lot of space. In urban areas, road surfaces cover about 1/5 of all available land. Rural roads in 1997 covered an estimated 13,363 square miles of land, an area larger the state of Maryland. Urban roads covered an additional 4,012 square miles, an area larger than Delaware.
Over 11 million automobiles were scrapped in 1996. About 75% of the scrapped material was recycled, while the remaining 25% was landfilled. In that same year, an estimated 266 million tires were scrapped, 76% of which was recovered and recycled, used as fuel, or exported to other countries. The 63 million tires that were not recovered were presumably dumped, adding to the approximately 800 million tires currently stockpiled in dumps around the country. These tire dumps, classified as an "ongoing environmental hazard" in one EPA report, are ideal breeding grounds for mosquitoes and a very serious fire hazard. When a tire dump catches fire, the burning tire casings emit toxic gases and are very difficult to put out completely. Some tires dumps have burned for more than a year.
Effects on Wildlife
The primary way people kill wildlife is not by hunting or trapping, but with their automobiles. It is estimated motor vehicles kill over a million animals in collisions every day in the US.
Most of the data for this page came from two US Environmental Protection Agency reports, Indicators of the Environmental Impacts of Transportation: Highway, Rail, Aviation, and Maritime Transport and Indicators of the Environmental Impacts of Transportation: Updated Second Edition. Energy data came from the U.S. Dept of Energy's Transportation Energy Data Book. Information on wildlife fatalities came from an Aug. 1, 2002, article in the Wall St. Journal, "In the Headlights: As Man and Beast Clash on Highways, Both Sides Lose" by James P. Sterba