Solar radiation, atmospheric pollution Meteorology Solar radiation, atmospheric pollution

Solar Radiation All energy is transmitted in the form of radiation. As the radiation passes through our atmosphere almost all of the energy that is shorter than visible light is reflected by the gases. In the stratosphere, the ultraviolet radiation is absorbed by the ozone layer. The infrared radiation is absorbed by the CO2 in the air. The gas, dust and water vapor in the air cause the radiation to be scattered. The radiation is either reflected back into space or bent in another direction. This is the reason why the sky is blue.

When the radiation reaches the earth’s surface, it is either absorbed or reflected. What happens is determined by looking at the earth’s surface composition (like color, mass, composition or texture). The greenhouse effect occurs when the atmosphere allows visible and infrared light to enter our atmosphere but pollution traps the radiation near the earth’s surface. The radiation continues to heat up the surrounding air as it slowly escapes. Humans contribute to the greenhouse effect by releasing carbon dioxide, which helps to increase the earth’s global temperature.

There is a difference in the time it takes for the radiation to be absorbed by the earth and when the atmosphere is actually heated up. This is called the temperature lag. The strongest radiation occurs at noon but the warmest time of the day is at 4pm.

Air Pollution Any substance in the air that is considered harmful to people, animals, plants, or property is called air pollution. The main source of air pollution is the burning of fossil fuels like coal and petroleum. As these are burned, they release chemicals into the air like hydrocarbons and lead. Air pollution can only be controlled by preventing the release of these harmful chemicals into the air. Certain weather conditions can make air pollution worse. A temperature inversion occurs when warm, less dense air (which rises) traps the cooler, more dense air underneath it. The air cannot circulate so air pollution is trapped. The topography of the land can actually make this worse.

A form of air pollution that concerned scientists in the 1980’s was chlorofluorocarbons (CFC’s). These particles, which were commonly found in refrigerators, air conditioners, and aerosol cans, had begun to destroy the ozone layer. The use of CFC’s was banned and the hole in the ozone layer has begun to repair itself.