From Ecopedia

Overview

Gasoline (also known as Petrol) is a liquid fuel mixture derived from petroleum for use in internal combustion engines that are commonly found in automobiles and machinery.

Comprising of aliphatic hydrocarbons, gasoline is obtained through petroleum distillation and enhanced octane rating.^[1] In addition to being used to power machinery, gasoline’s molecular make-up enables it to be used as a solvent, particular for it’s ability to dilute paint.

Most commonwealth countries use the term “Petrol” which is abbreviated from petroleum spirit, when referring to gasoline. Gasoline is also commonly referred to as motor spirit, petrol, gas or benzol, depending on the region where the fuel is sold.

Liquified Petroleum Gas or LPG is a high octane combustion fuel possessing a lower content of energy (per lit) compared to lower octane gasoline. As a result, LPG produces lowered overall power output.^[2]

Octane Rating

Octane rating, a chief attribute of gasoline, is a measure of gasoline’s resistance to pre-detonation or knocking (abnormal combustion). Octane rating is crucial for finding higher output powers of aircraft engines.

Environmental Impacts of Gasoline

Gasoline Production

Production of gasoline is carried out in oil refineries, which causes small quantities of oil to get mixed with gasoline. The petroleum-derived gasoline is then separated from the crude oil using fractional distillation process. Typically, gasoline is chiefly made up of hydrocarbons, which are classified as “hazardous” by the Occupational Safety and Health Organization in the US.

In total, gasoline is predominantly made up of paraffin (alkane) mixtures, olefins (alkenes) and naphthenes (cycloalkanes). In addition, gasoline might also contain many organic substances including deliberately added organic ether and small quantities of sulfur compounds.^[3]

Keeping in mind the ever-growing environmental regulations on automotive emissions, most petroleum oil refineries are striving to produce environment-friendly motor gasoline that guarantee reduced automotive emissions.

Environmental regulations are especially intended to check the levels of environmentally-hazardous lead, various aromatics including benezene, olefins as well as sulfur content in the gasoline.

In addition, the regulations also aimed to reduce nitrogen and toxic oxides (NOx and TOx), volatile organic compounds (VOCs) in tailpipe emissions of automobiles apart from refueling and evaporative emissions.^[4]

Sulfur Compounds

Sulfur compounds present in gasoline increase the toxic emissions of sulfur trioxide, besides causing corrosion and foul smell. Sulfur compounds are known to lower the efficiency of various catalytic converters as well as the energy efficiency of automobiles by adversely affecting the automobile ignition timing.

Recognizing such hazardous impact of sulfur’s presence in gasoline, environmental automotive fuel regulations are currently focusing on considerable sulfur reduction in gasoline, in future.

Countries like Germany and the US (California in particular) are already contemplating introducing a 10ppm sulfur specification in future to achieve significant reduction in sulfur content in gasoline.^[5]

Octane Enhancing Compounds

Octane enhancing compounds such as lead, benzene, olefins and aromatics, are proven to be environmentally hazardous due to the toxic nature of the compounds.

Various lead additives are found to be toxic air pollutants. Excepting very few countries, lead is being phased out in most parts of the world due to the carcinogenic nature of the substance.

Benzene too is a known carcinogenic. Aromatics and olefins, on the other hand, generate smoke and smog.^[6]

Greenhouse Emissions

Gasoline-powered automobiles release large amounts of greenhouse gases such as Carbon dioxide (CO2), Chlorofluorocarbons (CFCs) into the atmosphere. About 30% of the human-induced greenhouse emissions are related to transportation.

Greenhouse gases, after absorbing the infrared radiation, trap the generated heat making the earth’s atmosphere warmer by about 33°Celsius, producing the environmentally-hazardous Greenhouse effect.^[7]

References

1. ↑ http://en.wikipedia.org/wiki/Gasoline
2. ↑ http://en.wikipedia.org/wiki/Gasoline
3. ↑ http://en.wikipedia.org/wiki/Gasoline
4. ↑ http://www.cheresources.com/greengas.shtml
5. ↑ http://www.cheresources.com/greengas.shtml
6. ↑ http://www.cheresources.com/greengas.shtml
7. ↑ http://www.ocf.berkeley.edu/~coreyp/gasolineenvimp.html