Urban Air Pollution
The transportation sector is responsible for a large majority of air
pollutants in our urban areas, including carbon monoxide and nitrogen
oxides, which form ground-level ozone. Tens of millions of Americans
live in areas not meeting at least one federal air quality standard.
In 1990, Congress passed the Clean Air Act Amendments to combat high
emission levels of carbon monoxide, nitrogen oxides and the creation
of ground-level ozone by petroleum-based transportation fuels. This
Act specifically required the production and distribution of
cleaner-burning gasoline, containing oxygenates such as ethanol, in
America's most polluted cities. Tougher emissions standards are also
causing diesel engine users to find cleaner-air fuel options. Both
ethanol and bio diesel have been proven to reduce emissions that are
contributing to urban air pollution.
When ethanol is added to gasoline, it displaces gasoline components,
which generally reduces all pollutants. And because ethanol causes
fuels to burn more completely, it further reduces emissions of carbon
monoxide, volatile organic compounds, and toxic air emissions.
Bio diesel in a 20 percent blend with petroleum diesel reduces visible
smoke and odour, particulate matter, carbon monoxide, total
hydrocarbons, sulphur dioxide and lead. And when the blend is used
with an oxidation catalyst, particulate matter is reduced even more.
Water pollution associated with gasoline includes marine oil spills,
groundwater contamination from underground gasoline storage tanks and
runoff of vehicle engine oil and fuel.
Marine oil spills such as the Exxon Valdez Spill in Alaska in
1989-cause considerable environmental damage. Acute oil spills such as
the Valdez spill can damage individual organisms and wipe out entire
populations of marine and coastal species. They also require
large-scale, costly clean-up operations. Even more alarming, however,
is that marine oil spills such as the Valdez spill are not nearly as
damaging to the environment as the thousands of smaller spills that
are reported annually. Pipeline spills reported to the U.S. Department
of Transportation average 12 million gallons of petroleum products per
year. The Exxon Valdez Spill, by comparison, spewed out 11 million
gallons. According to the U.S. General Accounting Office, an average
of 16,000 small oil spills seep into waterways each year and estimates
that in recent years more than 46 million gallons have spilled per
Another source of water pollution from gasoline is groundwater
pollution. According to the U.S. Environmental Protection Agency, more
than a quarter of the nation's one million underground gasoline and
oil tanks leak, causing considerable groundwater contamination.
Besides direct oil spills and leakage,...