Automobiles, pollution

Poorly maintained automobiles pollute by emitting carbon monoxide and hydrocarbons, products of incomplete combustion. Because carbon monoxide is very poisonous and hydrocarbons contribute to the formation of smog, it is desirable to minimize the emission of bolh of these pollutants. 

FIGURE 18.16 (a) The arrangement of a catalytic converter used to reduce automobile pollution, (b) Cutaway views of several catalytic converters showing different structures for organizing metal catalysts, platinum, palladium, and rhodium on different substrates and supports. A steel-alloy heating element raises the temperature to 400 C in seconds, activating the catalysts and reducing the pollution emitted in the first minutes after the car is started. 

It has been proved that cerium is a very efficient additive in catalysts for the control of automobile pollutants. 

J.E. McEvoy, editor. Catalysts for the Control of Automobile Pollutants. Advarwes in Chemistry, Volume 143. American Chemical Society, Washington, D.C., 1975. 

The above assumption has been confirmed by a recent work on automobile pollution. The iron compoimds emitted into the atmosphere as exhaust were determined with the Mossbauer technique (25). The Mossbauer spectra of the deposit from the car exhaust revealed that the iron compoimds were mainly composed of hematite (a-Fe203) in the form of ultrafine particles 120 A in diameter. In general, we should... 

It was concluded that any remedy to regulated automobile pollutants (hydrocarbons, carbon monoxide) would decrease the polynyclear aromatic hydrocarbons. 

These have reduced automobile pollution by more than 1.5 billion tons since 1974. 

Qiapter 4 is a mostly new chapter dealing with air and pollution. It contains a significantly expanded treatment of this material in comparison to the previous edition. There is considerably more discussion of the relationships between percent, ppm, and ppb and the use of these concentration units in everyday situations. There is also a new discussion on automobile pollution regulations. 

R. Impens, in A. Crucq and A. Frennet, eds.. Catalysis and Automobile Pollution Control, Elsevier, Amsterdam, the Netherlands, 1987, pp 11—30. 

J. Dettling, Z. Hu, Y. Lui, R. Smaling, C. Wan, and A. Punke, in Proceedings of CAPoCg, Third International Congress on Catalyst and Automobile Pollution Control, Brussels, Belgium, April 20—22, 1994. 

The automobile pollutants in the atmosphere are exposed to intense sunlight, which yields photochemical oxidants. This phenomenon give rise to photochemical smog. Three specific eye irritants have been already identified in the photochemical smog— Formaldehyde, acrolein and peroxyactyl nitrate (PAN). The possible reaction sequence is as follows ... 

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