According to the government, gas mowers produce five-percent of all air pollution in the country.

In fact one hour of mowing produces as much pollution as driving your car 350 miles.

It's not surprising some old technology is making a comeback. More people are turning back the clock and using push mowers. Sales of non-gas powered mowers are up from last year.

The environment is just one reason. Some people like to get exercise while doing the yard.

Of course these aren't your Dad's push mowers. The technology has improved some. A few are even self-propelled. There are even battery powered mowers.

One word of caution: they're usually recommended for people with very small lawns.

Of course the news about gas engines isn't all bad.

Some fuel additives are being produced that reduce emissions as well.  A mineral-based 2-cycle engine oil is a good example.

Most new lawnmowers meet California emission standards. They're among the most stringent in the country.