FUELS FOR THE CARS OF TOMORROW
Driving is a dirty business. We add more pollution to our environment by running our internal combustion engines than we do with any other single activity. Auto exhaust, even "clean" exhaust, contributes about a quarter of all the carbon dioxide discharged into the air above the United States, as well as almost all of the carbon monoxide in and above our cities. The benzene that's in our gasoline is a known carcinogen, a cancer‐causing agent. The Environmental Protection Agency, a division of the federal government, estimates that auto exhaust produces about 1,800 cancers annually. Next time you fill your tank, look for a note on the gas dispenser telling you that "Long term exposure to vapors has caused cancer in some laboratory animals."
It seems clear that improving the health of our environment (and ourselves) requires, among other things, decreasing tailpipe emissions. This can take several forms. Auto manufacturers can design and produce cars that are more fuel‐efficient than those now on the roads, and therefore simply use less gasoline. In addition, gasoline manufacturers can formulate cleaner‐burning gasolines. Adding the oxygenates can lower carbon monoxide emissions, but it won't decrease carbon dioxide emissions and it might increase other forms of pollution. Another route would be to abandon the hydrocarbons of gasoline entirely. The four most promising alternatives are: electricity, ethanol, methanol and natural gas.
In any case, we will have choices before us, both as individuals and as a society. Whatever fuel or combination of fuels we do choose, it will be chemistry, in one form or another, that delivers the energy. Making the choices intelligently will require an understanding of the chemistry that lies behind them.
(SNYDER, Carl H. The Extraordinary Chemistry of Ordinary Things. John Wiley & Sons, Inc, 1995. p. 218-21.)
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