In 1990, the federal government passed amendments to the Clean Air Act that
set minimum standards for air quality in America's cities. These amendments
included provisions that required the use of oxygenated fuels by 1992 in nearly
all areas where excessive amounts of carbon monoxide (CO) existed. Beginning in
1995, the amendments required introduction of reformulated gasoline (RFG) in a
number of metropolitan areas where ground level ozone was excessive. Reformulated
gasoline also is required to contain an oxygenate. Since the majority of air pollution
is caused by vehicle exhaust, using cleaner burning fuels is one alternative that
provides rather immediate results. Ethanol is one oxygenated fuel being offered as
a solution.
Oxygenated Fuel Program Areas
The Metro Areas listed require wintertime use of oxygenated fuel. (1999)
El Paso, TX Reno, NV Missoula, MT
Colorado Springs, CO Grant's Pass, OR Provo, UT
Denver/Boulder, CO Klamath Co., OR Anchorage, AK
Ft. Collins, CO Medford, OR Las Vegas, NV
Phoenix, AZ Portland, OR Vancouver, WA
Los Angeles, CA Spokane, WA Minneapolis/St Paul, MN
Note: Minnesota has implemented the oxygenated fuels program throughout the state.
SOURCE: US EPA
Iowa is fortunate that it does not have any cities or counties that exceed the
Environmental Protection Agency's standards for CO. However, according to the Iowa
Department of Natural Resources (DNR), the Davenport area has exceeded EPA's ozone
standard on at least one occasion. Through continued and increased use of ethanol
blends, Iowa can maintain and improve its current air quality standards.
EFFECTS
Hydrocarbons (HC) are formed from products made from crude oil. Petroleum
and gasoline consists of blends of over 250 diverse hydrocarbons. Many of
these are toxic; some, such as benzene, are a carcinogen (cancer causing agent).
Hydrocarbons escape into the air during refilling the gas tank, from the gas
tank and carburetor during normal operation, and from engine exhaust.
Hydrocarbons which evaporate from gasoline are sometimes called volatile
organic compounds (VOCs). If uncontrolled, transportation sources would
make up 30% to 50% of the total hydrocarbon emissions into the atmosphere.
The automotive industry has developed and is using various vehicle control
systems that control HC emissions. Since ethanol is an alcohol based product,
it does not produce HC when being burned or during evaporation. HC also
contributes to the formation of ground level ozone.
Ozone, sometimes referred to as photochemical smog, is formed in the air when
hydrocarbons and nitrogen oxides react in the presence of sunlight. It is more
of a concern on warm, quiet, summer-like days when "smog" fills the air creating
a brownish haze in the lower atmosphere. This ground level ozone causes
human respiratory stress, and can cause plant damage, sometimes reducing
crop yields. This ground level ozone does not increase the ozone that is in the
stratosphere, and does not block the sun's harmful ultraviolet rays. Several U.S.
based studies conclude that, overall, the ozone forming potential of ethanol
blends, which vaporize at lower temperatures due to higher volatility, is about
the same as gasoline. In Canada, however, the volatility of ethanol blends must
match normal gasoline; therefore, the ozone forming potential is less than U.S.
ethanol blends. Reformulated fuel was introduced in 1995 to promote fewer
hydrocarbons and nitrogen oxides. Starting in 2000, reformulated gasoline
requirements are: 25 percent reduction in volatile organic compounds, 20 percent
reduction in toxics, and 5 percent reduction in nitrogen oxides. Volatile organic
compounds are mainly from vaporization of gasoline. Toxics are from chemicals
like benzene, aromatics, and olefins.
The shaded portions of the map indicate areas that are
required to use reformulated gasoline as of 1999.
SOURCE: US EPA FROM: CHANGES IN GASOLINE III SUPPLEMENT
Aldehyde emissions from the combustion of ethanol blends are slightly higher
than when burning gasoline. The concentrations are extremely small and are
sufficiently reduced by the vehicle's three-way catalytic converter found on all
recent cars. The Royal Society of Canada termed the possibility of negative health
effects caused by aldehyde emissions from the use of ethanol blends as being
"remote".
Carbon Monoxide (CO) is a poisonous gas formed by incomplete combustion. It
is readily produced from burning petroleum fuels which contain no oxygen in their
molecular structure. It is especially produced when excessive fuel to air mixtures
are delivered and burned in the engine. More fuel and less air is necessary to
start a cold engine and to keep it running until reaching normal operating
temperature. Vehicles operating at colder temperatures (in winter months, during
engine warm up, or in stop-and-go traffic) produce significant quantities of this
toxic gas. By adding ethanol, which contains oxygen, combustion in the engine
is more complete and CO is reduced. Research shows that reductions may reach
as high as 30% depending on the type and age of the automobile, the emission
system used, and the atmospheric conditions. Because of health concerns over
carbon monoxide, the 1990 amendments to the Clean Air Act mandate the use of
oxygenated fuels in many major urban areas (CO non-attainment areas) during
the winter months.
Carbon Dioxide (CO2) is a normal non-toxic product of burning fuel, but contributes
to the greenhouse effect (global warming). All petroleum based fuels cause
increased atmospheric carbon dioxide levels. Using renewable fuels, such as ethanol,
does not increase atmospheric carbon dioxide levels. The carbon dioxide formed
during combustion is balanced by that absorbed during the annual growth of plants
used to produce ethanol. Plants "breath" carbon dioxide and give off oxygen.
Therefore, increased use of renewable fuels made from plants will partially offset
the global warming effect of burning gasoline. It is also worth noting that
renewable fuel technology can result in a net reduction in atmospheric carbon
dioxide levels. This is accomplished by transforming carbon dioxide into
organic matter that is returned to the soil, thereby increasing soil fertility and
reducing erosion. Ethanol use in gasoline has tremendous potential for a
net reduction in atmospheric carbon dioxide levels.
Nitrogen Oxides (NOx) are produced when high combustion temperatures exist and
contribute to ground level ozone (photochemical smog). Several components of
gasoline that impact NOx emissions, including olefins and aromatics, are displaced
by using ethanol. EPA studies indicate the use of ethanol blends may slightly
increase NOx emissions, but the extent and effects are uncertain.
RESULTS
Both the oxygenated fuel and the reformulated gasoline programs have been
successful. The oxygenated fuel programs resulted in excellent program compliance
during the first year. In the winter of 1992-93, seven programs in the western
states had CO violations drop 50% compared to the previous year. Originally,
36 areas were designated as CO non-attainment areas. Today there are only 18
areas remaining that are required to use oxygenated gasoline because of their CO
non-attainment status. The use of reformulated gasoline has contributed to a
reduction of ozone (smog) forming emissions equivalent to removing 16 million
vehicles from the road per year. Use of oxygenated and reformulated fuels is a
quicker and more economical way of achieving reductions rather than implementing a
vehicle emission maintenance program that requires every vehicle be tested or repaired.
Ethanol is one of the best tools we have to fight air pollution. Ethanol reduces
pollution through the volumetric displacement of gasoline, and by adding oxygen
to the combustion process which reduces exhaust emissions. The use of ethanol
results in reductions in every pollutant regulated by the Environmental Protection
Agency (EPA), including ozone, air toxins, carbon monoxide, particulate matter, and
nitrogen oxides.
New model cars of the late 1990's and beyond will have On-Board Diagnostic
Monitoring systems capable of monitoring tailpipe and evaporative emissions.
Advances in computer technology not only improve monitoring and control of
emissions, but make it possible to use blends of up to 85% ethanol. These flexible
fuel vehicles will be able to sense the volume of ethanol with gasoline and make the
necessary engine adjustments for best efficiency, performance, and emission levels.
STUDY QUESTIONS
Matching: Place the letter of the term which best matches each statement in the
numbered blank provided.
A. aldehyde
B. carbon dioxide
C. carbon monoxide
D. hydrocarbons
E. nitrogen oxides
F. ozone
______ 1. Unburned fuel from evaporation of gasoline and incomplete
combustion.
______ 2. Non-toxic vapor produced by complete combustion.
______ 3. Produced during high combustion temperatures.
______ 4. A toxic vapor produced when burning excessively rich air
fuel mixtures.
______ 5. Created when unburned fuel vapors and nitrogen oxides react
when sunlight is present.
Essay: Completely answer the following question.
1. In 1992, use of oxygenated fuel was required in certain geographical areas where
carbon monoxide levels were excessive. How does burning ethanol in a vehicle
lower CO levels?
PROJECT
Unscramble the following words:
____________________ 1. THLANOE
____________________ 2. NOTCAE
____________________ 3. OSALINGE
____________________ 4. BRANCO NXOMOIDE
____________________ 5. SIMENOSIS
____________________ 6. RAING
____________________ 7. NORC
____________________ 8. HOLACOL
____________________ 9. NOZEO
____________________ 10. GYERNE
____________________ 11. HANNECER
____________________ 12. GENYXO
____________________ 13. BUYSIDS
____________________ 14. LOI
____________________ 15. RATDYEHDE
____________________ 16. ZRIBAL
____________________ 17. RAMEFR
____________________ 18. EUFL
____________________ 19. DRYHOBORCANS
____________________ 20. DEALUNED
____________________ 21. TEVINICEN
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