Primary air pollutants are released into the atmosphere in such great numbers that they can cause adverse health effects. They come directly from their sources, unchanged.
- Carbon monoxide (fossil fuel combustion, tobacco smoke)
- Nitrogen oxides (fossil fuel combustion)
- Particulates (fossil fuel combustion, farming, construction, industry, building demolition)
- Sulfur dioxide (fossil fuel combustion, smelting ore)
Secondary air pollutants, on the other hand, are created by the reactions between primary air pollutants and sunlight.
All of these pollutants have adverse health effects. Consequences include eye irritation, asthma, and sometimes (under the worst conditions) death.
- Carbon monoxide is a poison that prevents hemoglobin from binding to oxygen in the blood. Prolonged exposure leads to certain death.
- Particulates come in two varieties. The finest particles (less than 10 micrometers in diameter) are the most dangerous; when inhaled, they can lodge within the lungs and create problems such as bronchial irritation and future lung cancer; if they are absorbed by the blood they can cause poisoning.
- Sulfur dioxide and nitrogen oxides react with water vapor in the atmosphere to create acid rain. Acid rain strips trees of their leaves, leeches nutrients from soil, and alters the pH of lakes and streams.
- Ozone in the upper atmosphere plays an important role in protecting the earth from the sun’s ultraviolet radiation. When ozone is created close to the surface, however, it is a dangerous air pollutant. It aggravates asthma, reduces lung function, and irritates and damages the lungs; prolonged exposure leads to lung tissue scarring.
A Common Resource
Air is a common resource, one that we all must share. This makes it rather difficult to regulate. Although many countries are making attempts to reduce their toll on the world’s atmosphere, many others (especially those developing) have their priorities in other places.
Driven by the desire for a stronger economy, countries such as China have forsaken their environments for industry. Unfortunately, the rest of the world must deal with the consequences. China’s air pollution doesn’t just hover above China – it is blown across oceans to pollute other countries. In San Francisco, soot from Chinese factories has been detected in record numbers; in Japan, numerous health problems have sprung from imported Chinese air.Goto the top of this page.
The Greenhouse Effect
Our atmosphere serves the important role of insulating our planet against the chill of outer space; without the greenhouse gases in the atmosphere, the Earth would be too cold to support life. So why do people talk about greenhouse gases like they’re a bad thing?
The issue is not that greenhouse gases exist; the issue is that their levels in the atmosphere have been increasing exponentially in recent years. Carbon dioxide levels, specifically, have been increasing due to the incomplete combustion of fossil fuels. But what does this mean?
Carbon dioxide levels have reached historical highs, and scientists predict that if we do not curb CO2 emission, the average global temperature of the earth may increase by as much as 7°C (check) by 2100. Although this doesn’t seem like a very big change, it may lead to such environmentally devastating consequences as melting permafrost, disappearing ice caps, rising sea levels, and increased heatstroke deaths around the world.Goto the top of this page.
The Ozone Layer and CFCs
Ozone in the stratosphere plays an integral role in the protection of life on Earth. It protects the planet from the sun’s damaging ultraviolet rays, which can alter the DNA of cells and cause problems from burning to cancer.
Chlorofluorocarbons are produced by a number of products including air conditioners, refrigerators, industrial cleaners, and aerosols. These chemicals float into the upper atmosphere; when they reach the stratosphere, they react with the highly volatile ozone, breaking it apart. In this way the use of CFCs can thin the ozone layer. An ozone “hole” has even appeared over Antarctica, and a smaller one is forming over the Arctic.
If these ozone holes increase in size, the effects may be devastating. In areas like Australia, the incidence of skin cancer is already increasing. Burning and cancer will become more prevalent, and other forms of life sensitive to UV radiation will surely be affected. For example, algae in the Antarctic may be killed off by the radiation, damaging local food chains.Goto the top of this page.