Hybrid Car Pollution

Hybrid car pollution and fuel use may be reduced up to 42% compared to similar gas powered cars. The average pollution reduction for 29 current hybrids shown on the list below is however about 23%. The average fuel reduction is 21%.

So, in the short term hybrid reductions in pollutants and fuel are beneficial.
In the long term though, hybrids will continue to pollute and use large amounts of fuel. As the chart below shows for example hybrid sales or increased driving miles only need to increase by an average of 23% to
offset all CO2 savings.

Hybrid Car Pollution CO2:

Manufacturers provide CO2 as well as other pollutant data for their vehicles. The CO2 data is usually in the format of grams per kilometer. The Toyota website for example, lists the new Prius as producing "as low as" 89 g/km
of CO2. These results are based on UK testing using the Imperial gallon.

This comes out to 19.3 pounds of CO2 per US gallon of gasoline burned.
The US EPA uses 19.4 pounds per gallon based on a few different assumptions. Using these figures, you have to do the math to get an idea
of just how much the Prius pollutes per year for example. We use
20 pounds CO2 / gallon gas for quick math.

The Quick Math:

Multiply your vehicle Gallons of gas used x 20 = pounds of CO2 per gallon.
Gallons x 20 = pounds CO2.

Hybrid vehicle gallons of gas can be estimated from the charts here, here, here or from the EPA. Just take the miles you drive and divide it by the fuel economy of that vehicle.

Or, the US EPA lists carbon output as Tons per Year. The Prius is listed as making 3.7 Tons of CO2 annually. This is based on driving 15,000 miles and
a 55% city / 45% highway split on the fuel use.