Benefits of Urban Trees Trees Reduce Air Pollution Trees and other plants make their own food from carbon dioxide in the atmosphere, water, sunlight and a small amount of soil elements. In the process, they release oxygen for us to breathe. Trees: Help to settle out, trap and hold particle pollutants (dust, ash, pollen and smoke) that can damage human lungs. Absorb carbon dioxide and other dangerous gasses and, in turn, replenish the atmosphere with oxygen. Produce enough oxygen on each acre for 18 people every day. Absorb enough carbon dioxide on each acre, over a year's time, to equal the amount you produce when you drive your car 26,000 miles. Trees remove gaseous pollutants by absorbing them through the pores in the leaf surface. Particulates are trapped and filtered by leaves, stems and twigs, and washed to the ground by rainfall. Air pollutants injure trees by damaging their foliage and impairing the process of photosynthesis (food making). They also weaken trees making them more susceptible to other health problems such as insects and diseases. The loss of trees in our urban areas not only intensifies the urban "heat-island" effect from loss of shade and evaporation, but we lose a principal absorber of carbon dioxide and trapper of other air pollutants as well. Some of the major air pollutants and their primary sources are: Carbon dioxide: Burning oil, coal, natural gas for energy. Decay and burning of tropical forests. Sulfur dioxide: Burning coal to generate electricity. Hydrogen fluoride and silicon tetrafluoride: Aluminum and phospate fertilizer production, oil refineries, and steel manufacturing. Ozone: Chemical reactions of sunlight on automobile exhaust gases. Ozone is a major pollutant in smog. Methane: Burning fossil fuels, livestock waste, landfills and rice production. Nitrous oxides: Burning fossil fuels and automobile exhausts. Chlorofluorocarbons: Air conditioners, refrigerators, industrial foam. The burning of fossil fuels for energy and large scale forest fires such as in the tropics are major contributors to the buildup of carbon dioxide in the atmosphere. Managing and protecting forests and planting new trees reduces carbon dioxide levels by storing carbon in their roots and trunk and releasing oxygen into the atmosphere. « Return to the main page for the Benefits of Urban Trees.