Ozone is one of the most concerning pollutants of the day. Ground-level ozone is a primary component of urban smog and can do tremendous damage to human health. Our stereotypical ideas about how ozone pollution results, however, are many times inaccurate.
Ground-level ozone differs from ozone in the upper atmosphere. While the latter is actually beneficial, ground-level ozone presents a number of concerns. Atmospheric ozone is an important feature in protecting the earth from the harmful rays of ultraviolet light. Ground-level ozone, in contrast, is only deleterious.
Ground-level ozone has been associated with a variety of health problems. Its impacts on respiratory function are particularly concerning. The pollutant directly impacts the cellular structure of the respiratory system, actually burning through the cell walls of the lungs just minutes after entering the body. This allows cellular fluid to escape into the lungs. Breathing becomes labored. As more and more cells are destroyed the cellular structure of the lungs and the ciliated cells of the nose and airways are replaced with abnormal thick-walled squamous cells. The lungs stiffen and breathing is impacted even more heavily.
Ozone pollution is somewhat perplexing because it is not directly traceable to specific sources. Instead, ground-level ozone is formed as a byproduct of other pollutants. Coal-fired electrical plants are one of the primary contributors to the problem. These plants emit volatile organic compounds and the oxides of nitrogen. These pollutants are precursors to ozone. On hot sunny days they combine to produce ozone.
Unfortunately, coal-fired electrical plants are just one of many sources for the precursors of ozone. Nitrogen oxides are produced by numerous sources that burn fossil fuels. Automobiles and other internal combustion engines such as lawnmowers and boat engines are among the most prolific of these sources.
Nitrogen oxides are also emitted from many less visible sources. Oil-based paints, solvents, wood-burning fireplaces, water heaters, boilers, gas stations, restaurants, and various consumer products are all producers of ozone precursors. Even natural vegetation emits volatile organic compounds that have the potential to form ozone!
Obviously, controlling ozone pollution is a difficult proposition. While clean air standards have been put in place nationally and even regionally for many areas, the fact remains that a tremendous amount of ozone is already in the air. More, of course, is being produced daily but that production comes from such a large diversity of sources that initiating measures that will effectively address the problem is almost impossible. How can we possibly regulate such activities as back yard barbecues, the use of home fireplaces and children’s go-carts, the type of paints we utilize, and hundreds of other seemingly innocent activities?
While it is easy to impose standards for acceptable ozone levels, it is more difficult to enact measures to counteract existing ozone levels and to effectively limit the future production of ozone precursors. While we can implement emissions testing for automobiles and emission standards for power plants, it is practically impossible to regulate all of the activities that produce the constituents that ultimately form ozone.