Health Effects of Ozone and Particle Pollution cont'd

In 1996, the City of Atlanta hosted its first Olympic games. In the news that summer were the stories of the success of the athletes, as well as of the tragic bombing. However, something that wasn’t publicized -- until much later -- was the unexpected impact the Olympics had on the health of Atlanta residents. And that story tells us much about the possibilities of a city with much less air pollution.

To make it easier for people to get to the games, Atlanta increased available public transportation, limited downtown motor vehicle use (especially in the mornings), and encouraged telecommuting and alternate work hours for businesses. Peak ozone concentrations decreased dramatically -- by more than 25 percent -- during the Olympics compared to the 4-week periods before and after. Some reductions were also seen in other pollutants like carbon monoxide and particles. 32 The effect that the decreased ozone concentrations and lower levels of particle pollution had on the health of the residents of Atlanta was astonishing and at the same time makes perfect sense -- especially when you know more about ozone and particles.

Ozone (O3 ) is an extremely reactive gas composed of three oxygen atoms. It is the primary ingredient of smog air pollution and very harmful to breathe. Ozone essentially attacks lung tissue by reacting chemically with it. It also damages crops, trees and other matter -- even breaking down rubber compounds.

News about ozone can be confusing. Some days you hear that ozone levels are too high and other days that we need to prevent ozone depletion. Basically, the ozone layer up in the upper atmosphere (the stratosphere) is beneficial because it shields us from much of the sun’s ultraviolet radiation. However, ozone air pollution at ground level where we can breathe it (in the troposphere) is anything but beneficial. It causes serious health problems.

Ozone isn’t emitted directly. The raw ingredients for ozone, nitrogen oxides (NOx ) and hydrocarbons, or volatile organic compounds (VOCs), are produced primarily when fossil fuels are burned or when fossil fuel-based chemicals evaporate. These molecules combine and form ozone when they come in contact with both heat and sunlight. NOx is emitted from motor vehicles, power plants and other sources of high-heat combustion. VOCs are emitted from motor vehicles, chemical plants, refineries, factories, gas stations, paint, and other sources.

You may have wondered why "ozone action day" warnings are sometimes followed by recommendations to avoid activities such as mowing your lawn or filling your gas tank during daylight hours. It’s because lawn mower exhaust and lost gasoline vapors turn into ozone in the heat and sun. And of course, automobile exhaust does the same thing. So it would follow that just before the summer of 1996, the residents of Atlanta were about to drastically reduce the amount of ozone in their air by reducing output of NOx and VOCs.

The effects of ozone on lung health have been studied at length using laboratory animals, clinical subjects, and human populations. The results are clear: ozone causes serious respiratory harm at levels currently experienced in the U.S.

Five groups of people are especially vulnerable to the effects of breathing ozone. They are: children, senior citizens, people who work or exercise outdoors, people with pre-existing respiratory disease (i.e., asthma or COPD), and "responders" who are otherwise healthy but have an enhanced reaction to ozone.

The effect that ozone has on an individual’s health can vary depending onwhether they fall into a susceptible population group, what the ozone concentration level is, and how long they are exposed to it.

Many areas in the U.S. produce enough ground-level ozone during the summer months to cause health problems that can be felt right away. These immediate problems are:

• shortness of breath,
• chest pain when inhaling deeply,
• wheezing and coughing.
• increased susceptibility to respiratory infections.

Exposure to ozone greatly increases:

• pulmonary inflammation
• the risk of asthma attacks, and
• the need for medical treatment and for hospitalization of persons with asthma.33

Short-term exposure to ozone has also been linked to aggravation of chronic obstructive pulmonary disease (COPD).34 Over time, the repeated inflammation due to exposure to ozone over a period of years can lead to a chronic "stiffening" of the lungs.

Health Effects continued...