A Cleaner Breath

A Cleaner Breath

Automobile emissions and their effects on our environment and our health has been a widely debated topic over the last few decades. The automobiles we use today emit large quantities of toxins that deteriorate the quality of air we breathe. Concerns over this phenomenon rose among very few people over half a century ago. Nowadays, concerns for the environment are commonly held, and everyone needs to be aware of the impacts our environment faces. The last century has witnessed a huge growth in the automotive and oil industries. This growth in automobile usage and fossil fuel consumption has also contributed to the deterioration of the air we breathe and the environment that we live in. The most common fuel in transportation is gasoline, which release harmful toxins into the atmosphere when it is combusted to run motors (Clean Air.) Our environment is constantly irritated by large quantities of poisons released from the tailpipes of our vehicles. A poisonous mix consisting of a combination of unburned Hydrocarbons, Carbon Monoxide and Nitrogen Oxides is choking the atmosphere.

Pollution has cast its ominous shadow across the world. Two of the pollutants that are emitted by automobiles are hydrocarbons (unburned fuel) and nitric oxide. When these pollutants build up to sufficiently high levels, a chain reaction occurs from their interaction with sunlight in which the NO is converted to nitrogen dioxide (NO2). NO2 is a brown gas and at sufficiently high levels can contribute to urban haze, hence the smog that laypeople in big cities complain about.

However, a more serious problem is that NO2 can absorb sunlight and break apart to produce oxygen atoms that combine with the O2 in the air to produce ozone (O3). Ozone is a powerful oxidizing agent, and a toxic gas. In North America elevated levels of tropospheric ozone cause several billion dollars per year damage to crops (45 million/per year in Ontario), structures, forests, and human health. It is believed that the natural level of ozone in the clean troposphere is 10 to 15 parts-per-billion. Due to the increasing concentrations of hydrocarbons and NO2 in the atmosphere, scientists have found that ozone levels in "clean air" are now approximately 30 parts-per-billion (Atmospheric Chemistry). Even if the sky above you seems to be clear and blue, smog is everywhere. "It is a choking sensation every time one ventures out into the streets" (Smog).

What we typically call smog is primarily made up of ground-level ozone. Ozone can be good or bad depending on where it is located. Ozone in the stratosphere high above the Earth protects human health and the environment, but ground-level ozone is the main harmful ingredient in smog. Ground-level ozone is produced by the combination of pollutants from many sources, including smokestacks, cars, paints, and solvents. For example, when a car burns gasoline, this process releases exhaust fumes and these smog-forming pollutants rise into the sky. When fossil fuels (e.g., gasoline) are burned, a variety of pollutants are emitted into the earth's troposphere, the region of the atmosphere in which we live.

Weather and geography determine where smog goes and how bad it is. When temperature inversions occur, warm air stays near the ground instead of rising. If winds are calm, smog may stay in place for days at a time. As traffic and other sources add more pollutants to the air, the smog gets worse. Often, wind blows smog-forming pollutants away from their sources. The smog-forming reactions take place while the pollutants are being blown through the air by the wind. This explains why smog is often more severe miles away from the source of the smog-forming pollutants than it is at the source. The smog-forming pollutants literally cook in the sky, and if it's hot and sunny, smog forms more easily. Just as it takes time to bake a cake, it takes time to cook up smog. It takes several hours from the time the pollutants enter into the air until the smog becomes harmful.

Since smog is blind, nothing stops smog and air pollutants from crossing county and state lines. When a metropolitan area covers more than one state (for instance, the New York metropolitan area includes parts of New Jersey and Connecticut), their governments and air pollution control agencies must cooperate to solve their problem. Governments on the East Coast from Maine to Washington, D.C. are working together in an interstate effort to reduce the area's smog problem.

In 1990, the Clean Air Act was passed in an effort to clean up our planet. Here's how the Clean Air Act reduces pollution from criteria air pollutants, including smog: First, The Environmental Protection Agency, or EPA, and state governors cooperated to identify "nonattainment" areas for each criteria air pollutant. These are areas where the air pollutants usually exceed the national standards. Then, the EPA classified the nonattainment areas according to how badly polluted the areas are. There are five classes of nonattainment areas for smog, ranging from marginal, relatively easy to clean up quickly, to extreme, in which a large amount of work and a time are needed to clean up (Cleaner Emissions). The Clean Air Act uses this new classification system to tailor clean-up requirements to the severity of the pollution and set realistic deadlines for reaching clean-up goals. If deadlines are missed, the law allows more time to clean up, but usually a nonattainment area that has missed a clean-up deadline will have to meet the stricter clean-up requirements set for more polluted areas. Not only must nonattainment areas meet deadlines, states with nonattainment areas must show the EPA that they are making moves to clean up the air before the deadline, making reasonable further progress. States will usually do most of the planning for cleaning up criteria air pollutants, using the permit system to make sure power plants, factories and other pollution sources meet their clean-up goals. The comprehensive approach to reducing criteria air pollutants taken by the 1990 Act covers many different sources and a variety of clean-up methods. Many of the smog clean-up requirements involve motor vehicles (cars, trucks, buses). Also, as the pollution gets worse, pollution controls are required for smaller sources. However the EPA recently reviewed the current air quality standards for ground-level ozone, or smog, and particulate matter (or PM). Based on new scientific evidence, revisions have been made to both standards. At the same time, EPA is developing a new program to control regional haze, which is largely caused by particulate matter. Under the Clean Air Act, the EPA is required to study whether and how to reduce hazardous air pollutants from small neighbourhood polluters such as auto paint shops, print shops, etc.