Air and Us

As early as we’ve cultivated the earth and lit fires, we have been impacting air. Taking away the earth’s plant cover exposes the soil to increased wind erosion. Fires create more particles. Depending on what we burn and how well it is burned, varying amounts of nitrous oxides, sulfur oxides, carbon dioxide and carbon monoxide are formed. We have always assumed that the vastness of our air and its movement as wind would dilute these contributions and carry them "away," but as population densities increased, we began running into problems with this line of thinking. In 61 AD, the Roman author, Seneca, wrote of the "soot" and "heavy air" of Rome. And, in 1257, the Queen of England had to leave London because of poor air quality. It is not hard to imagine, then, as population densities continued to grow and the industrial revolution with its advances in technology occurred, more burning and increased production led to more of a load for the air to carry away. Today, 90 percent of what can be considered air pollution is there because of people. Of special concern is this pollutant load during temperature inversions. These inversions are natural weather events that trap warmer air next to the earth with a blanket of colder, heavier air. When the lower air can’t carry away the pollutants because of this blanket effect, serious air quality problems for the immediate area can result.

Stunning air pollution events in the 1940s and 50s resulted in many deaths. These events led to the use of technology and laws to effect an improvement in air quality. In the United States, the first Clean Air Act was passed in 1970, sparked by a general increase in environmental awareness and concern led by Rachel Carson and other prominent environmental thinkers. Now scientists ponder, not without controversy, the grander scale of air pollution, and model the long term effects of this global problem.

Today, the air we breathe in the US is polluted with nearly 200 million tons of emissions each year. For 1990, statewide emissions inventories are sobering. See Pa. 1990 Statewide Emission Inventory list on pages 27and 28. The US Environmental Protection Agency (EPA) estimates that outdoor air toxins cause about 3,000 new cases of cancer each year, with half of those caused by vehicle emissions! Acute respiratory distress incidents, absence from work and increased medical expenses are directly linked to air pollution. Pollution standards set by government agencies are based on protecting public health. Yet air pollution over all, even at levels below those set to protect human health, may result in damage to trees, plants and agricultural crops over time. Livestock, wild animal populations and aquatic life are affected. Particulates deposited on plants may be incorporated into the food chain by plant eaters. Air pollution decays rubber, iron and nylon; it makes paint peel and discolor, and it blocks natural sunlight to plants and decreases visibility. Acid rain, one result of air pollution that is prominent in Pa., is particularly corrosive to buildings, statues and other structures. Damage to materials and the environment can lead to enormous restoration costs.