GENERAL POLLUTION FACTS

How is pollution related to weather?

Pollution—both natural and man-made—has numerous, often complex effects on the weather. Air pollutants, for instance, can cause acid rain, and pollution that destroys the ozone layer can lead to health risks to people and even wipe out species. Many scientists believe that human-generated pollution is causing climate change, which affects weather patterns on a global scale. While some pollutants, such as gases from volcanic eruptions, can have harmful consequences, many meteorologists, environmentalists, and climatologists fear that human activity is having a much bigger, negative impact on the weather and our health than anything currently occurring from natural sources.

What is long range transport?

Long range transport refers to the fact that winds—especially high-altitude winds— can carry pollutants over incredibly long distances. People once believed that pollutants from sources such as smoke stacks might travel a few miles before settling onto the ground and water supplies. Now it is known that these particulates and toxic gases can make their way into the upper atmosphere. Scientists first started to become aware of this issue in the mid-twentieth century, when nuclear bomb tests resulted in radioactive clouds that would circumnavigate the planet. Acid-rain-causing chemicals can easily cross the entire United States, and, likewise, pesticides and herbicides travel long distances. Natural air pollutants, such as volcanic ash and organic material like fungi, spores, and pollen, can similarly range over long distances.

What major energy source is considered to be the cleanest?

Natural gas is regarded as the cleanest-burning fossil fuel, producing less pollution than oil or coal.

What is an urban heat island?

Because urban areas are generally devoid of significant vegetation, the concrete and other construction materials for buildings and roads prevent the heat from the Sun from being absorbed. Instead, surfaces become hotter and drier. Cities and towns become warmer than surrounding rural areas to the point where, on a warm summer day, surfaces such as sidewalks and roofs can be as much as 50° to 90°F (27 to 50°C) hotter than the surrounding air. The warming effects are especially pronounced during the day, but the temperatures are also affected at night.

According to the U.S. Environmental Protection Agency, a city of about one million people can cause the surrounding atmosphere to heat up as much as 22°F (12°C) more than it would be under similar weather conditions in a rural area. Annually, the effect would be that the overall temperature for a city that size would be 1.8 to 5.4°F (1 to 3°C) higher than in the surrounding areas. There are several problems that result from heat islands: people tend to use their air conditioners and other utilities more, thus increasing energy consumption; this leads to more pollution, including greenhouse gases; these pollutants also affect human health; finally, rainwater that has fallen onto heated surfaces on pavement and roofs flows into sewers, and then into the environment, where the heated water affects wildlife.

What is an urban ice slab?

Just as urban areas can cause problems related to heat, they also can make winters more hazardous. When ice forms on skyscrapers and other tall buildings, a dangerous situation may arise upon thawing. Large sheets of ice have been known to break

It's easy to see the extent of light pollution in this image of nighttime lights across the globe. (NASA)

It's easy to see the extent of light pollution in this image of nighttime lights across the globe. (NASA)

off of structures and plummet to the streets below. One notable case of this happening occurred in Chicago, Illinois, in April 1995, when the danger of urban ice slabs dropping onto Michigan Avenue compelled authorities to close the street for hours.

What is light pollution?

While not harmful to people or other living things, light pollution is an annoyance to astronomers. Light from cities makes it difficult to see stars and other heavenly bodies at night, which is why observatories are stationed on top of mountains and hills outside of urban areas. It is also why space observatories such as the Hubble Telescope are so important for astronomers.

What is odor pollution?

Odor pollution is simply the unpleasant stench of such things as garbage, sewage, chemicals, rotting organic matter, and hazardous waste. Human beings can detect foul odors at concentrations as low as one part per trillion, depending on what the chemical is. This is important because people can actually detect air pollutants (except for odorless ones such as carbon monoxide) at levels much lower than can be detected by instruments. This is especially true of the smellier pollutants, such as hydrogen sulfide (H2S), which produces that familiar rotten egg smell, even when diluted in water. Hydrogen sulfide pollution can cause everything from eye and throat irritation to asthma attacks and even death.

 
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