Polymeric materials atmospheric pollutants

These reactions may add to the reactions caused by polluted atmosphere. They are particularly possible at temperatures near those where changes or property transitions occur (for example at softening and melting points or brittle points of the materials). Service Life of Polymeric Materials in Polluted Atmosphere... 

In the modern urban atmosphere, 03 may be the pollutant of particular concern for health. However, it is a reactive gas that will also attack the double bonds of organic molecules (see Section 2.7) very readily. Rubber is a polymeric material with many double bonds, so it is degraded and cracked by 03. Tyres and windscreen wiper blades are especially vulnerable to oxidants, although newer synthetic rubbers have double bonds protected by other chemical groups, which can make them more resistant to damage by 03. 

Air pollution is usually defined as the presence in the outdoor atmosphere, of substances put there directly or indirectly by an act of man, in amounts which are detrimental to health and safety or interfere with the fulJ jise of materials or property, e.g. made from polymeric materials. Man is not the only agent able to pollute the atmosphere. There are many natural processes that do so such as pollination of plants, volcanic emptions, dust stormes and forest fires. There are also secondary pollutants in the atmosphere, formed in the air from primary pollutants, due to acts by man, e.g. smoke, industrial pollutants and photochemical smog formed in the air from substances emitted from automobile exhaust and other sources. 

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