Air pollution is the presence of any substance in the atmosphere in quantities high enough to endanger the health of humans, animals, and plants. Numerous types of pollutants can be emitted in some ways, but they are commonly divided into two categories: natural and human.
Human emission sources can be classified as either point or mobile. Point sources are fixed in one area, such as a power plant, and emissions may be traced back to that source. Mobile sources, on the other hand, include motor vehicles, whose emissions cannot be clearly tracked to a single vehicle and are frequently considered as an aggregate instead.
As metropolitan populations grow in size and density, air pollution becomes increasingly prevalent. Typical phenomena in major cities include industrial and photochemical smog, which occurs when significant amounts of pollutants are injected into the atmosphere in a short time, generating a variety of negative impacts that are discussed below and on other pages linked to this page.
Types of air pollution
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Urban air pollution
When numerous contaminants are injected into the atmosphere, especially in large numbers over a small area, the air quality deteriorates. These pollutants can be emitted by a variety of sources, but automobiles that burn gasoline and other petroleum products are the most significant contributors within cities. Coal combustion emits numerous dangerous chemicals; nevertheless, in most parts of the world, coal is burned relatively distance from cities, therefore air pollution from coal plants has a less obvious impact on air quality.
Nitrogen oxides, sulfur oxides, particulate matter, volatile organic compounds, and other contaminants all contribute to poor air quality. These are classified as main pollutants because they are discharged directly into the atmosphere. The bulk of them also react in the air, producing secondary pollutants such as ozone and peroxyacyl nitrates (PANs). Many of these contribute to the creation of smog and photochemical smog, which can linger over a given region for a dangerous period.
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Global air pollution: greenhouse gases
Greenhouse gas emissions, such as carbon dioxide and methane, are of worldwide significance because of the warming effect they have in the atmosphere. This sort of air pollution is less obvious daily than urban pollution, making it more difficult for people to understand the negative effects of these pollutants. Many signs of a warming globe, such as increasing sea levels and ocean heating, support the impact of these gases on the global climate.
Currently, CO2 levels in the oceans and atmosphere are rising, and this growth is primarily due to human activities, known as anthropogenic carbon emissions. Carbon dioxide is released during the process of hydrocarbon combustion, which occurs when hydrocarbon-rich fossil fuels are burned to generate energy. This can come from a variety of sources, including an automobile’s exhaust gas and a coal-fired power plant smokestack.
Effects
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Health issues
Air pollution can cause a variety of negative impacts, including poor visibility, trouble breathing, sickness, and even death. Many Asian countries suffer the most from poor air quality and everyday smog, which contribute to a large number of deaths from lung and heart disease. Many developing countries around the world are facing the same problems.
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Acid rain
Acid rain happens when water in the atmosphere reacts with nitrogen and sulfur oxides and falls to the ground. It is approximately 25 times more acidic than typical rain and has numerous negative impacts on plants, lakes, fish, houses, and other structures. It can also induce respiratory illnesses in people, particularly those in poor condition. When lakes and other bodies of water become overly acidic, with a pH of less than 6.0, vegetation and aquatic life suffer. Fish reproduction ability deteriorates, with mortality or deformities prevalent among younger fish. Amphibians and invertebrates suffer similarly, therefore acidic lakes have little to no animal life.
Prevention and mitigation
The key to controlling air pollution is to prevent it from occurring in the first place. Numerous methods can be used to do this, including scrubbers, electrostatic precipitators, and others. For more information on how to cope with air pollution, please visit our air pollution control devices page.
Most wealthy countries have recognized the effects of air pollution in recent years, resulting in increasingly stringent pollution control measures. For example, Canada relies on government initiatives to minimize emissions from companies, vehicles, and other sources, resulting in improved outdoor air quality.
The line graph below is generally used to indicate whether or not overall emissions levels in Canada have improved, notably as a result of efforts to clean flue gasses with various air pollution control equipment. The drop-down menu allows you to select different contaminants. For more details on what causes these pollutants, please refer to comprehensive pollution statistics. Environment Canada provides a province-by-province time series.
