How does ozone pollution differ from the ozone layer?
• • The ground-level ozone in the lower atmosphere (troposphere) should not be confused with the natural protective layer of ozone in the upper atmosphere (stratosphere). Although both are made of the same molecules (ozone), the ozone in the upper atmosphere protects us from the sun’s harmful ultraviolet (UV) rays, while the ozone in the lower atmosphere harms us. Nitrogen Oxide (NOx) Facts Nitrogen oxides are a major contributor to ozone production and smog. • • Diesel engines produce nearly 20% of the total NOx in outdoor air and 26% of the total NOx from on-road sources Carbon Dioxide (CO2) Facts • • About 33% of U.S CO2 emissions come from the burning of gasoline in internal-combustion engines of cars and light-trucks (minivans, SUV’s and pick-up trucks) • • Vehicles with poor gas mileage contribute the most to global warming, according to U.S. Emissions Inventory 2006(PDF) Carbon Monoxide (CO) Facts • • Carbon monoxide (CO) is an odorless, colorless, poisonous gas that comes from
