According to the text, the kind of pollution that is thought...

Pollution

Thick black smoke curling out of smokestacks, horrible-tasting chemicals in your drinking water, pesticides in your food - these are examples of pollution. Pollution is any contamination of the environment which causes harm to the environment or the inhabitants of the environment. There are many kinds of pollution, and there are many pollutants. Some obvious kinds of pollution are pollution of the air, soil, and water. Some less obvious, or less salient kinds of pollution are radioactive, noise, light pollution, and green-house gasses.

Air pollution can be caused by particles, liquids, or gases that make the air harmful to breathe. There are two main types of air pollution: primary and secondary. Primary pollutants enter the air directly, like smoke from factories and car exhaust. Secondary pollutants are chemicals that mix together to pollute the air, like mixtures of emissions, or waste output, from vehicles and factory smoke that change to form more dangerous pollutants in the air and sunlight.

Soil pollution can be caused by pesticides, leakage..........................chemical tanks, oil spills, and other chemicals..........................get into the soil by dumping or accidental contamination. Soil pollution can also cause water pollution.............................underground water becomes contaminated by coming.............................contact with the polluted soil.

Water pollution can be caused by waste products, sewage, oil spills, and litter in streams, rivers, lakes, and oceans. Some scientists believe that water pollution is the largest cause of death and disease in the world, causing about 14,000 deaths in the world each day.

Radioactive pollution can be caused by leaks or spills of radioactive materials. These materials can come from medical sources, nuclear power plants, or laboratories which handle radioactive materials. Air, soil, and water can be polluted by radioactivity. It can cause damage to animals, both internally and externally, by eating, drinking, or touching it. It can cause birth defects and genetic problems. It can cause certain cancers and other deadly diseases.

Noise pollution can be caused by vehicle, aircraft, and industrial noise. It can also be caused by military or experimental sonar. Noise has health effects on people and animals. In people, it can cause high blood pressure, heart problems, sleep disturbances, and hearing problems. In animals, it can cause communication, reproductive, and navigation problems – they have difficulty finding their direction. Sonar has even caused whales to beach themselves because they respond to the sonar as if it were another whale.

Light pollution can be caused by advertising signs, stadium and city lighting, and other artificial lighting (like the light caused by night traffic). Artificial lighting has health effects on humans and animals. In people, it can cause high blood pressure and affect sleeping and waking rhythms and immunity. It might be a factor in some cancers, such as breast cancer. In animals, it can affect sleeping and waking rhythms, navigation, and reproduction.

In addition, greenhouse gases have caused a warming effect on the earth’s climate. The greenhouse gases are water vapor, carbon dioxide, methane, and ozone. They are naturally–occurring gases in the atmosphere, but human activity has increased their concentration in the atmosphere. For example, the levels of carbon dioxide (CO2) in the atmosphere have risen due to the burning of fossil fuels. The effect is a rise in global temperatures. The higher temperatures cause the melting of glaciers, a rise in the water level of oceans, and the disruption of both land and marine life, including that of humans. Although carbon dioxide is necessary for plants to survive, it is also considered to be a kind of pollution because high levels of carbon dioxide have caused the oceans to become more acidic.

It is not possible for anyone to predict the exact timing and effects of global pollution and global climate change brought about by pollution. There is general agreement by scientists that the global climate will continue to change, that the intensity of weather effects will continue to increase, and that some species of animals will become extinct. There is also general agreement, or consensus, that humans need to take steps to reduce emissions of waste products and greenhouse gases into the atmosphere, make adaptations to the changes that are occurring, and figure out ways of reversing the trends of pollution and global warming.