A Cleaner Breath
Uploaded by susanR on Feb 17, 2007
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...