Gasoline or petrol, light, volatile mixture of hydrocarbons for use in the internal-combustion engine and as an organic solvent, obtained primarily by fractional distillation and "cracking" of petroleum, but also obtained from natural gas, by destructive distillation of oil shales and coal, and by a process that converts methanol to gasoline using zeolite as a catalyst. Gasoline intended for use in engines is rated by octane number , an index of quality that reflects the ability of the fuel to resist detonation and burn evenly when subjected to high pressures and temperatures inside an engine. Premature detonation produces "knocking" and "pinging" ; it wastes fuel and may cause engine damage. The addition of tetramethyl lead and tetraethyl lead to raise the octane number is no longer permitted in the United States because it leads to dangerous emissions containinglead. New formulations of gasoline designed to raise the octane number contain increasing amounts of aromatics and Oxygen-containing compounds (oxygenates), such as alcohols, methyl tertiary butyl ether (MTBE), and methylcyclopentadienyl Manganese tricarbonyl (MMT). Automobiles are now equipped with catalytic converters that oxidize unreacted gasoline; the cars are designed to run on newly formulated gasolines as well as on gasohol , which contains 10% ethanol or 3% methanol. In addition, since 1998 a number of American automobiles have been equipped to enable them to run on either gasoline or E85, a mixture of 85% Ethanol and 15% gasoline. Some racing cars use pure Methanol as fuel.
 History of Gasoline
The history of gasoline begins with the first oil well in 1859. The petroleum was used to produce kerosene for lighting. In 1892, the invention of the automobile prompted an interest in gasoline as a fuel. By 1920, 9 million automobiles were on the roads, so service stations began showing up everywhere. By 1950, cars were becoming more complex, so octane levels were increased and lead was added to the gas to improve the performance of the engine. However, lead leads to health issues, so the 1970s saw the removal of lead from gasoline.
We all know that gasoline comes from crude oil. The media is always reminding us of how much it costs per barrel. But what is gasoline chemistry? What is done to crude oil that turns it into gasoline? Below is a list of the chemicals you will find in your car’s gasoline:
Hydrocarbon Octane, which has an engine cleaning effect Aromatic hydrocarbons such as Benzine and Toluene Paraffins Cyclic alkalines Alkenes and Polyenes Alkyl sophates that prevent engine filters from becoming clogged
 Gasoline Facts
Here are some gasoline facts to make you think a little:
- In the U.S. alone there are over 234 million vehicles in operation that drive up to 12,000 miles per year.
- There are 164,292 fueling stations.
- Over 60% of the fuel that is used for transportation is in the form of gasoline.
- Gasoline emits Carbon dioxide, which is a greenhouse gas that is harmful to the Environment.
- These are just some of the gasoline facts that can really make you think. As for the future of gasoline as a fuel, much work is being done to find more efficient and environmentally safe fuels to relieve our dependence upon oil.
There are five blends of gasoline marketed in the United States.
- Conventional gasoline, the most widely available, is sold where air quality is satisfactory; since 1992, it has been formulated to evaporate more slowly in hot Weather so as to reduce smog, and it now contains detergent additives to reduce engine deposits.
- Winter oxygenated gasoline, introduced in 1992, is formulated as conventional gasoline with oxygen-rich chemicals added, such as MTBE or Ethanol. The Oxygen promotes cleaner burning, reducing carbon monoxide, and is generally sold from November to March because cold engines operate less efficiently and produce more Carbon monoxide.
- Reformulated gasoline (RFG), introduced in Jan., 1995, is mandated in areas where toxins in the air are a constant problem; it contains Oxygen-rich chemicals in lesser concentrations than the winter oxygenated gasoline and is formulated to reduce certain toxic chemicals found in conventional and winter oxygenated fuels.
- Oxygenated reformulated gasoline is a wintertime fuel exclusive to the New York City area, where heavy carbon monoxide Pollution occurs.
- California reformulated gasoline, introduced in 1996, has a different formulation and burns cleaner than regular reformulated gasoline. Because MTBE has been implicated as a pollutant, particularly of groundwater, its use is being curtailed. In 1999, California ruled that the MTBE in California reformulated gas must be phased out by Dec. 31, 2002.
 What is gasoline?
Gasoline is made from processed crude oil and is a pale brown or pink liquid with a strong odor. It evaporates easily, is very flammable and can form explosive mixtures in air. Typical gasoline contains about 150 different chemicals, including benzene, toluene, ethylbenzene and xylene, which also are known as the BTEX compounds.
Gasoline also contains chemicals such as lubricants, anti-rust agents and anti-icing agents that are added to improve car performance. These chemicals usually are only present in very small amounts. Before the 1980s, lead was commonly used in gasoline as an anti-knocking agent. The use of lead has been stopped due to Air pollution and the possibility of adverse health effects. Some gasolines also contain Ethanol, which is made from corn. Ethanol helps a car run more efficiently and it produces less pollution. The most common additive used in gasoline is methyl tertiary-butyl ether (MTBE). It is added to increase octane and Oxygen levels and reduce Pollution emissions.
 How does gasoline get into the Environment?
Spills, leaks or improper disposal of gasoline can cause contamination of Soil, Groundwater, surface water and air. Leaking underground storage tanks or pipelines also can cause gasoline to enter surrounding soil and Groundwater. Gasoline can be released into the air when large tanker trucks are filled and emptied and when you fill your car at the service station.
 How can I be exposed to gasoline?
You can be exposed to gasoline by
- breathing gasoline vapors,
- drinking water contaminated with gasoline, or touching gasoline or Soil or Water contaminated with gasoline.
The most common exposure to gasoline occurs by breathing vapors when filling your car’s fuel tank. Vapors also can be present in air when gasoline evaporates out of contaminated Soil or Water. Gasoline vapors can build up in basements, crawlspaces and living areas.
When gasoline seeps into soil, it can contaminate groundwater used for drinking. Most chemicals in gasoline are removed during water treatment, but people who drink untreated water or water from private wells can be exposed. Gasoline also can be absorbed through skin during contact, such as when pumping gas or cleaning up a gasoline spill.
 Health effects of gasoline exposure
Many adverse health effects of gasoline are due to individual chemicals in gasoline, mainly BTEX, that are present in small amounts. Breathing small amounts of gasoline vapors can lead to nose and throat irritation, headaches, dizziness, nausea, vomiting, confusion and breathing difficulties. Symptoms from swallowing small amounts of gasoline include mouth, throat and stomach irritation, nausea, vomiting, dizziness and headaches. Some effects of skin contact with gasoline include rashes, redness and swelling. Being exposed to large amounts of gasoline can lead to coma or death.
The health effects of being exposed to gasoline over long periods of time are not well known. This is because people exposed to gasoline are usually exposed to many other things that also can cause health effects. Some workers who are exposed to gasoline every day in their jobs have suffered memory loss and decreased muscle function. At very high levels, some of the chemicals in gasoline, such as benzene, are known to cause Cancer. Current evidence, however, does not show that exposure to low levels of gasoline causes cancer in humans.
 Can I be tested for gasoline exposure?
There are laboratory blood or urine tests that can determine if you have been exposed to gasoline, but these tests are not generally available in your doctor’s office. These tests measure BTEX compounds in your body, which may be present as a result of exposure to sources other than gasoline.
 How can I reduce my exposure to gasoline?
Due to the widespread use of gasoline in cars, trucks, buses and lawn care equipment, eliminating exposure would be difficult. Typically, you can smell gasoline at levels that would not be expected to cause adverse health effects. Since gasoline can be smelled at low levels, the source can usually be found and eliminated.
If you suspect that your Water supply is contaminated with gasoline, here are a few ways to reduce your exposure:
If gasoline is in your well water, do not drink it. Consider using bottled Water for drinking and cooking, using a water treatment unit certified to remove gasoline chemicals, or connecting to a public water supply.
Shower or wash in cooler water. Wash and rinse clothes in cold water. The hotter the water, the more gasoline evaporates into the air you breathe.
Air out bathrooms, washrooms and kitchens during and after water use by opening doors and windows and turning on exhaust fans.