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Once up to temperature a catalyser reduces the exhaust gases to pretty much just the following;
CO2
H2O
N2
It converts nasty gases like CO, NO2, NO3, H2O2 and a whole plethora of unburnt or part burnt hydrocarbons to the above "safe" gases.
That said, CO2 is still a greenhouse gas and in high concentrations can suffocate you, but it's nowhere near as dangerous as CO (Carbon monoxide) which kills in relatively low concentrations. The other nasties are NO2 & NO3 which dissolve in water to produce Nitric and Nitrous acids (these are the ones that used to rot your exhaust from the inside out) which cause breathing problems as the acids damage the linings of your lungs.
Unburnt and part-burnt hydrocarbons are carcinogens and some can form organic acids which are also nasty for your breathing.
Cats are a good thing but they are not the be-all and end-all as they produce more greenhouse gas since anything with carbon in it in the exhaust gases produces more CO2.
What is needed are leaner burning motors (invented but scrapped as they can't run cats), and optimally another way of producing the power for a vehicle. Until they come along the Cat is what we have.
Yes it damages the environment (most platinum, rhodium & palladium mines are open-cast and some of the extraction techniques are not exactly enviromentally friendly) but it prevents your kids from coughing their lungs up.
As with everything there is NO BLACK AND NO WHITE, only shades of grey. At the moment the internal combustion engine with a Cat is a lighter shade of grey than one without a Cat. Hopefully, that will soon change.
Last edited by Boomer : 05-28-2008 at 07:22 AM.
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