photo credit: oxyboricua
Have you ever thought what (other than the smog hanging over the cities of the world) constitutes air pollution? And what exactly does it mean in terms of global warming?
Well, simply speaking, the air pollution is basically any substance people emit into the atmosphere that has damaging effects on the environment.
That said, there are various kinds of pollution; some visible, like smog, others not. The most commonly known pollutant is carbon dioxide, which is also considered the main greenhouse gas contributing to global warming. CO2 is emitted every time any living creature breathes however most people associate it with cars, planes and other human activities involving burning fossil fuels. Over the last two centuries the steady growth of CO2 emissions combined with deforestation on increasingly larger scales resulted in raising the carbon dioxide levels higher than they have been for thousands of years previously. And that, of course, causes the warming of the earth’s climate.
Methane and chlorofluorocarbons (CFCs) are another type of greenhouse gasses. The former one comes from livestock and swamps, while the latter were used in refrigerants and aerosols until, luckily, they were banned when scientists discover their damaging effects on the ozone layer.
Sulfur dioxide is an element of smog (yet another air pollutant) and known mainly as a cause of acid rains. However, sulfur dioxide and similar chemicals in the atmosphere reflect light which, in turn, keeps the sun out and helps the planet cool. Volcanic eruptions used to be the main source of sulfur dioxide present in the atmosphere and sometimes cooled the Earth for years. With the industrial revolution, however, human activities took over the sulfur dioxide emissions.
Since this particular chemical is part of smog along with smoke and other constituents, many cities have worked to reduce its levels. Ironically, lower sulfur dioxide levels may aggravate global warming. How? Whether it comes from the volcanoes or humans, sulfur dioxide has been proven to cool the planet by blocking the sun rays. And with other greenhouse gasses trapping the heat, perhaps it is what we need to at least slow down the warming of the planet’s climate?
