The recent forest fires in the western portion of the state have reminded us of how much air pollution is of natural origin. When we hear the words, “air pollution,” our thoughts immediately go towards things like automobile emissions and industrialization. While these man-made sources of air pollution are significant contributors to pollution in our atmosphere, did you know that there are several natural processes and sources across the globe that also contribute to air pollution? This month, we briefly highlight some of these sources and how they contribute naturally to polluting the earth’s atmosphere.
- sulfur dioxide (SO2)
- nitrogen oxides (NOx)
- ozone (O3)
- volatile organic compounds (VOC)
Natural sources of sulfur dioxide include forest fires, volcanoes, and biological decay. It can be difficult to quantify the volumes of naturally-produced sulfur dioxide. “In 1983 the United Nations Environment Program estimated a figure of between 80 million and 288 million tons of sulphur oxides per year (compared to around 69 million tons from human sources world-wide).” (from www.enviropedia.org).
Nitrogen oxides are also released by volcanoes and biological decay, as well as the oceans and lightning strikes. “Estimates range between 20 million and 90 million tons per year nitrogen oxides released from natural sources (compared to around 24 million tons from human sources worldwide).”