Smog hanging over cities is the most familiar and obvious form of air pollution. But there are different kinds of pollution, some visible and some invisible, that contribute to global warming. Generally any substance that people introduce into the atmosphere that has damaging effects on living things and the environment is considered air pollution.
Carbon dioxide, a greenhouse gas, is the main pollutant that is warming Earth. Though living things emit carbon dioxide when they breathe, carbon dioxide is widely considered to be a pollutant when associated with cars, planes, power plants, and other human activities that involve the burning of fossil fuels such as gasoline and ...view middle of the document...
Just as sulfur dioxide from volcanoes can cool the planet by blocking sunlight, cutting the amount of the compound in the atmosphere lets more sunlight through, warming the Earth. This effect is exaggerated when elevated levels of other greenhouse gases in the atmosphere trap the additional heat.
Most people agree that to curb global warming, a variety of measures need to be taken. On a personal level, driving and flying less, recycling, and conservation reduces a person’s carbon footprint which is the amount of carbon dioxide a person is responsible for putting into the atmosphere.2
On a larger scale, governments are taking measures to limit emissions of carbon dioxide and other greenhouse gases. One way is through the Kyoto Protocol, an agreement between countries that they will cut back on carbon dioxide emissions. Another method is to put taxes on carbon emissions or higher taxes on gasoline, so that people and companies will have greater incentives to conserve energy and pollute less.2
There are many different chemical substances that contribute to air pollution. These chemicals come from a variety of sources. Among the many types of air pollutants are nitrogen oxides, carbon monoxides, and organic compounds that can evaporate and enter the atmosphere. Air pollutants have sources that are both natural and human. Now, humans contribute substantially more to the air pollution problem.
Forest fires, volcanic eruptions, wind erosion, pollen dispersal, evaporation of organic compounds, and natural radioactivity are all among the natural causes of air pollution. Usually, natural air pollution does not occur in abundance in particular locations. The pollution is spread around throughout the world, and as a result, poses little threat to the health of people and ecosystems.3
The findings, reported in the American Journal of Epidemiology, add to evidence that high-pollution days may trigger heart attacks in some people and like other studies, the new one suggests that the elderly and people with existing heart or lung disease are most vulnerable. Already, the American Heart Association (AHA) recommends that people with heart disease and others at risk -- including the elderly and people with diabetes or high blood pressure -- try to steer clear of congested roadways and spend less time outside on days when air quality is poorer.
The evidence of harm is strongest against pollutants known as fine particulate matter. Fine particulate matter is released into the air when wood or fossil fuels are burned, so car exhaust, home heating and industrial sources like power plants all contribute. The particles are small enough that they can be inhaled deeply into the lungs, and researchers suspect they may trigger heart attacks in vulnerable people by causing inflammation in the blood vessels and irritating the nerves of the lungs.4
For the new study, researchers of the Regional Health Service of Tuscany, looked at data on 11,450 hospitalizations for...