When scientists of psychologists think of depression or unhappiness, the first thing they wish to do is find the things that are making people or society unhappy. Canadians have studied that air pollution is one of the things that makes people unhappy or depressed, mentally. Their study was taken by fourteen different countries where they measured the difference in air pollution and took surveys of the “happiness levels” of people. They analysed carbon dioxide emission for overall pollution. This study had shown that the less pollution, the happier people acted and were. The improvement of heath care by policy makers would definitely make a difference in their citizens life satisfaction.