Green spaces are critically important for increasing the health of city dwellers. First, green spaces can lower the levels of pollution in city air. Trees actually help clean the air of pollutants, and their photosynthetic process replaces carbon dioxide with oxygen and can slow down the greenhouse effect.
Second, green spaces help combat the urban heat island effect. Cities tend to be several degrees warmer than rural areas. All the pavement and buildings capture the heat generated by industries, transportation, and people and hold it in. Hotter cities lead to greater efforts to cool them off and a greater consumption of energy as people use air conditioners and fans. Green spaces provide areas where heat can naturally rise freely and cooler air can settle and spread.
Third, green spaces can allow natural ecosystems to return to the midst of cities. A variety of tree species can provide shelter for many kinds of insects and birds that in turn increase the health of the trees. Small animals can also find homes in green spaces.
Fourth, green spaces provide places of beauty and relaxation for stressed city dwellers as well as opportunities to interact with nature. People who regularly spend time in nature tend to be calmer and healthier, and studies even suggest that they may live longer. Certainly, city dwellers will enjoy the fresher air, quieter environment, and cooler temperatures of green spaces as well as the ability to exercise or relax in places that are pleasant to the senses.