Winter-proof equipment each fall. New, cleaner gasoline equipment is entering the market and electric equipment is cleaner than equipment powered by gasoline engines. In addition, alternative fuel options such as propane and solar energy are becoming more available all the time. Check out the electric options. Electrically-powered lawn and garden tools produce essentially no pollution from exhaust emissions or through fuel evaporation.
Electric equipment is often easier to use and maintain, uses less energy, and operates more quietly.
However, generating the power to run electric equipment does produce pollution. Consider propane and solar options which are also available for some types of equipment. As the availability of these options spreads, significant emission reductions can be achieved. Use manual tools. Tools that don't require electric or gasoline engines are especially handy for small yards or small jobs.