Your Planet

Some Facts on Automobiles and the Environment

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".

Energy Use

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.

Air Pollution

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 source: Federal Highway Administration Transportation Air Quality: Selected Facts and Figures 2002 Water Pollution

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.

Noise Pollution

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).

Land Use

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.

Solid Waste

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.

So what does the future have in store for us?

Urban population growth


Urbanization, the demographic transition from rural to urban, is associated with shifts from an agriculture-based economy to mass industry, technology, and service. For the first time ever, the majority of the world's population lives in a city, and this proportion continues to grow. One hundred years ago, 2 out of every 10 people lived in an urban area. By 1990, less than 40% of the global population lived in a city, but as of 2010, more than half of all people live in an urban area. By 2030, 6 out of every 10 people will live in a city, and by 2050, this proportion will increase to 7 out of 10 people. Currently, around half of all urban dwellers live in cities with between 100 000 - 500 000 people, and fewer than 10% of urban dwellers live in megacities (defined by UN HABITAT as a city with a population of more than 10 million).


Globally, urban growth peaked in the 1950s, with a population expansion of more than 3% per year. Today, the number of urban residents is growing by nearly 60 million every year. The global urban population is expected to grow roughly 1.5% per year, between 2025-2030. By the middle of the 21st century, the urban population will almost double, increasing from approximately 3.4 billion in 2009 to 6.4 billion in 2050.

Almost all urban population growth in the next 30 years will occur in cities of developing countries. Between 1995 and 2005, the urban population of developing countries grew by an average of 1.2 million people per week, or around 165 000 people every day. By the middle of the 21st century, it is estimated that the urban population of these countries will more than double, increasing from 2.5 billion in 2009 to almost 5.2 billion in 2050. Nonetheless, on average, the rate of urban population growth is slowing in developing countries, from annual rate of roughly 4% from 1950-1975 to a projected 1.55% per year from 2025-2050.

In high-income countries, on the other had, the urban population is expected to remain largely unchanged over the next two decades, increasing from 920 million people to just over 1 billion by 2025. In these countries, immigration (legal and illegal) will account for more than two-thirds of urban growth. Without immigration, the urban population in these countries would most likely decline or remain static.

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