Over time cars get cleaner due to federal regulations and technological improvements, but population growth means that there are more cars on the road. People drive a moderate amount due to an increase in public transportation and ability to make some daily trips without a car. About 35% of vehicles on the road are electric/zero emissions due to expansion of charging stations, incentives, and other measures. Building emissions are reduced due to higher standards for energy efficiency. Slightly increased up-front costs may be offset over time by lower energy use. Due to all of these factors, air pollutants are produced at moderate levels, as shown in the chart above. In addition, greenhouse gas emissions, which contribute to climate change, are reduced by changes to the vehicle fleet and building energy efficiency. About 20% of the county’s electricity needs are produced by local solar panels or wind turbines, further reducing greenhouse gas emissions. The average household annually produces 13.1 metric tons of greenhouse gasses from building energy use and 4.2 tons of greenhouse gases from vehicle use.
