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Human activity is a major cause of air pollution, much of which results from industrial processes. Credit: cherwell. The Chiwaukum Fire in Washington State in Emissions by vehicles are a major cause of anthropogenic air pollution. Credit: ucsusa. Provided by Universe Today. Citation : What causes air pollution?
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Aerosols are tiny particles that can penetrate deep into the lungs and cause heart and pulmonary disease. Other agricultural air pollutants include pesticides, herbicides, and fungicides. All of which also contribute to water pollution. Nutrient pollution is caused by wastewater, sewage, and fertilizers. The high levels of nutrients in these sources end up in bodies of water and promote algae and weed growth, which can make the water undrinkable and depleted oxygen causing aquatic organisms to die.
Pesticides and herbicides applied to crops and residential areas concentrate in the soil and are carried to the groundwater by rainwater and runoff. For these reasons anytime someone drills a well for water it must be checked for pollutants. Industrial waste is one of the main causes of water pollution, by creating primary and secondary pollutants including sulphur, lead and mercury, nitrates and phosphates, and oil spills. This causes serious problems including the harming and killing of sea creatures, which ultimately affects humans.
This occurs when humans apply chemicals such as pesticides and herbicides to the soil, dispose of waste improperly, and irresponsibly exploit minerals through mining. Soil is also polluted through leaking underground septic tanks, sewage systems, the leaching of harmful substances from landfill, and direct discharge of waste water by industrial plants into rivers and oceans. Rain and flooding can bring pollutants from other already polluted lands to soil at other locations.
Over-farming and over-grazing by agricultural activities causes the soil to lose its nutrient value and structure causing soil degradation, another type of soil pollution. Landfills can leach harmful substances into the soil and water ways and create very bad smells, and breeding grounds for rodents that transmit diseases. Noise is considered an environmental pollutant caused by household sources, social events, commercial and industrial activities, and transportation. Light pollution is caused by the prolonged and excessive use of artificial lights at night that can cause health problems in humans and disrupt natural cycles, including wildlife activities.
Sources of light pollution include electronic billboards, night sports grounds, street and car lights, city parks, public places, airports, and residential areas. Pollution ends up in these forms including dust, smog, and toxic gas emissions. Smoke from a factory in one country drifts into another country.
Now, coal-burning power plant s in Texas and the neighboring state of Chihuahua, Mexico have spewed so much pollution into the air that visitors to Big Bend can sometimes see only 50 kilometers 30 miles.
The three major types of pollution are air pollution , water pollution , and land pollution. Air Pollution Sometimes, air pollution is visible. A person can see dark smoke pour from the exhaust pipes of large trucks or factories, for example. More often, however, air pollution is invisible. Polluted air can be dangerous, even if the pollutants are invisible. It can also increase the risk of lung cancer.
Sometimes, air pollution kills quickly. In , an accident at a pesticide plant in Bhopal, India, released a deadly gas into the air. At least 8, people died within days. Hundreds of thousands more were permanently injured.
Natural disaster s can also cause air pollution to increase quickly. When volcano es erupt , they eject volcanic ash and gases into the atmosphere. Volcanic ash can discolor the sky for months. After the eruption of the Indonesian volcano of Krakatoa in , ash darkened the sky around the world.
The dimmer sky caused fewer crop s to be harvested as far away as Europe and North America. Volcanic gas es, such as sulfur dioxide , can kill nearby residents and make the soil infertile for years. Mount Vesuvius, a volcano in Italy, famously erupted in 79, killing hundreds of residents of the nearby towns of Pompeii and Herculaneum.
Most victims of Vesuvius were not killed by lava or landslide s caused by the eruption. They were choked, or asphyxiate d, by deadly volcanic gases. In , a toxic cloud developed over Lake Nyos, Cameroon. Lake Nyos sits in the crater of a volcano. Though the volcano did not erupt, it did eject volcanic gases into the lake. The heated gases passed through the water of the lake and collected as a cloud that descend ed the slopes of the volcano and into nearby valleys.
As the toxic cloud moved across the landscape, it killed birds and other organisms in their natural habitat.
This air pollution also killed thousands of cattle and as many as 1, people. Most air pollution is not natural, however. It comes from burning fossil fuel s—coal, oil , and natural gas.
When gasoline is burned to power cars and trucks, it produces carbon monoxide , a colorless, odorless gas. The gas is harmful in high concentration s, or amounts.
City traffic produces highly concentrated carbon monoxide. Cars and factories produce other common pollutants, including nitrogen oxide , sulfur dioxide, and hydrocarbon s.
These chemicals react with sunlight to produce smog , a thick fog or haze of air pollution. The smog is so thick in Linfen, China, that people can seldom see the sun. Smog can be brown or grayish blue, depending on which pollutants are in it. Smog makes breathing difficult, especially for children and older adults. Some cities that suffer from extreme smog issue air pollution warnings.
The government of Hong Kong, for example, will warn people not to go outside or engage in strenuous physical activity such as running or swimming when smog is very thick. When air pollutants such as nitrogen oxide and sulfur dioxide mix with moisture, they change into acid s. They then fall back to earth as acid rain. Wind often carries acid rain far from the pollution source.
Pollutants produced by factories and power plants in Spain can fall as acid rain in Norway. Acid rain can kill all the trees in a forest. It can also devastate lake s, stream s, and other waterways. Acid rain also wears away marble and other kinds of stone.
It has erased the words on gravestone s and damaged many historic buildings and monument s. The Taj Mahal , in Agra, India, was once gleaming white. Years of exposure to acid rain has left it pale. Governments have tried to prevent acid rain by limiting the amount of pollutants released into the air. In Europe and North America, they have had some success, but acid rain remains a major problem in the developing world , especially Asia. Greenhouse gas es are another source of air pollution.
Greenhouse gases such as carbon dioxide and methane occur naturally in the atmosphere. In fact, they are necessary for life on Earth. They absorb sunlight reflected from Earth, preventing it from escaping into space. By trapping heat in the atmosphere, they keep Earth warm enough for people to live. This is called the greenhouse effect. But human activities such as burning fossil fuels and destroying forests have increased the amount of greenhouse gases in the atmosphere.
This has increased the greenhouse effect, and average temperature s across the globe are rising. The decade that began in the year was the warmest on record. This increase in worldwide average temperatures, caused in part by human activity, is called global warming. Global warming is causing ice sheets and glacier s to melt. The melting ice is causing sea level s to rise at a rate of 2 millimeters 0. The rising seas will eventually flood low-lying coast al regions.
Entire nation s, such as the island s of Maldives, are threatened by this climate change. Global warming also contributes to the phenomenon of ocean acidification. Ocean acidification is the process of ocean waters absorbing more carbon dioxide from the atmosphere.
Fewer organisms can survive in warmer, less salty waters. The ocean food web is threatened as plants and animals such as coral fail to adapt to more acidic oceans. Scientists have predicted that global warming will cause an increase in severe storm s.
It will also cause more drought s in some region s and more flooding in others. The change in average temperatures is already shrinking some habitats, the regions where plants and animals naturally live. Polar bears hunt seals from sea ice in the Arctic. The melting ice is forcing polar bears to travel farther to find food, and their numbers are shrinking.
People and governments can respond quickly and effectively to reduce air pollution. Chemicals called chlorofluorocarbons CFCs are a dangerous form of air pollution that governments worked to reduce in the s and s. CFCs are found in gases that cool refrigerators, in foam products, and in aerosol can s. When people are exposed to more ultraviolet radiation, they are more likely to develop skin cancer, eye diseases, and other illnesses.
In the s, scientists noticed that the ozone layer over Antarctica was thinning. But Australia, the home of more than 22 million people, lies at the edge of the hole. In the s, the Australian government began an effort to warn people of the dangers of too much sun. Water Pollution Some polluted water looks muddy, smells bad, and has garbage floating in it. Polluted water is unsafe for drinking and swimming. Some people who drink polluted water are exposed to hazardous chemicals that may make them sick years later.
Others consume bacteria and other tiny aquatic organisms that cause disease. The United Nations estimates that 4, children die every day from drinking dirty water. Sometimes, polluted water harms people indirectly. They get sick because the fish that live in polluted water are unsafe to eat. They have too many pollutants in their flesh. NO 2 , an airborne pollutant created mainly by vehicles and power plants that burn fossil fuels, can cause respiratory diseases in humans.
There are signs that atmospheric concentrations of other harmful pollutants, including particulate matter, toxic sulphur dioxide and carcinogenic formaldehyde emitted by industrial sources, have dropped too. But data are still preliminary, and some of the improvement could be down to natural weather variations. But thorough analysis of space observations of air pollution is still lacking, and scientists must investigate how lower atmospheric concentrations of various pollutants correspond to decreasing traffic and industrial emissions.
Climate vs coronavirus: Why massive stimulus plans could represent missed opportunities. The concentration of NO 2 and other airborne pollutants, including near-surface ozone, which chemically interacts with nitrates, is subject to large day-to-day variability. Favourable weather in early spring might have contributed to the observed drop in local air pollution in recent weeks, Eskes says. But compared with previous years, the decreases in NO 2 concentrations in China and Italy appear to be unprecedented, says Eskes.
The situation is fuzzier in the United States. The caveat, he says, is that it has been unusually rainy there in the last few weeks.
So it is still unclear what fraction of the observed improvement in pollution is due to favourable weather and what fraction is due to COVID precautions.
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