AIR POLLUTION: CAUSES, CONSEQUENCES, POLLUTANTS - ENVIRONMENT - 2025

The air pollution is the introduction of extraneous air components or alteration of normal composition which is harmful to living things. By definition, any element present in the atmosphere that affects human health is a pollutant.

The balance of the composition of the atmosphere can be affected by natural and anthropic causes (human action). Natural causes include the emission of gases from volcanic activity, forest fires and thawing of the tundra.

Air pollution from the paper industry. Source: Estormiz 08:22, 24 September 2006 (UTC)

The anthropic causes of air pollution are diverse and they can generate polluting gas emissions. Among these are industrial activity, automobile traffic, burning of fossil fuels and fires of man-made origin.

Air pollution results in a decrease in air quality that affects the respiration of living organisms. It also causes respiratory diseases in humans and other animals, and some pollutants are precursors of acid rain.

On the other hand, greenhouse gases are responsible for the increase in the average temperature of the Earth. The phenomenon of global warming causes great imbalances in the functioning of the planet.

Countries have different degrees of air pollution from various causes. In Latin America, Mexico and Peru are considered the countries with the worst air quality and Mexico City the city with the greatest problems.

To control air pollution it is necessary to take measures to reduce the emission of polluting gases. In this sense, legal measures must be taken that lead to the reduction of gas emissions into the atmosphere.

Likewise, dependence on fossil fuels must be reduced and the use of clean energy (hydroelectric, solar, wind, geothermal) should be increased. Similarly, it is necessary to stop deforestation and implement reforestation programs in the affected areas.

Causes

Atmospheric pollution by fossil fuels. Source: Alfred T. Palmer

Pollution of the atmosphere can be caused by the presence of polluting gases or polluting material particles. These can be generated naturally or by human activity.

The natural causes are mainly spontaneous forest fires and the thawing of the tundra which releases CO2. However, these factors do not have a major impact on air quality.

Human activities particularly associated with industrial development are those that produce the highest gas emissions into the atmosphere. Among these we have:

Industrial gas emissions

Industrial processes emit into the atmosphere different gases such as dioxins generated in the paper industry. For its part, the petrochemical industry produces CO2, nitrogen oxides and sulfur oxides, among other compounds.

The energy industry is the one that contributes the most to CO2, SO2 and mercury emissions due to the use of coal and gas as fuel.

Automotive traffic

Automotive traffic is responsible for most of the CO2 added to the atmosphere. On the other hand, combustion in diesel vehicles emits hundreds of gaseous and solid substances into the atmosphere.

Among the gases produced are carbon monoxide and dioxide, sulfur dioxide, nitrogen oxides, hydrocarbons and their derivatives. Furthermore, 90% of the NO2 in the atmosphere originates from the burning of diesel.

On the other hand, particles such as elemental carbon, organics and sulfur sulfates are emitted.

Burning of fossil fuels

Petroleum

Processing oil to generate gasoline, diesel, lubricants, plastics, and other by-products produces a large amount of polluting gases and particles. Among the gases released are carbon monoxide, sulfur dioxide and 30% of the CO2 that pollutes the atmosphere.

Coal

In many countries, coal is still the most widely used heating fuel. During its combustion, large amounts of SO2 are produced and mercury is released into the atmosphere.

Domestic combustion

It is estimated that combustion in homes is responsible for 12% of global pollution by environmental fine particles (PM2.5).

Forest fires

Wildfires release millions of tons of greenhouse gases and acid rain into the atmosphere annually. These include carbon dioxide and monoxide, methane, and nitrogen oxides.

On the other hand, they incorporate particles of different diameters into the environment that pollute the air and affect health.

Agriculture and Livestock

Rice

The rice growing system produces a large amount of methane that enters the atmosphere. This is because this plant is grown in swamps where bacteria decompose organic matter under anaerobic conditions and generate methane.

It is estimated that rice cultivation worldwide can contribute up to 20% of the methane that is incorporated into the atmosphere.

Sugarcane

The management of this crop involves controlled burning prior to harvest, which becomes a source of CO2 and fine particles to the atmosphere.

Ruminant livestock

Ruminants are able to consume fibrous grass thanks to fermentation processes carried out by bacteria in their digestive system. Ruminant livestock is estimated to be responsible for about 18% of the methane generated into the atmosphere.

Consequences

Air pollution from automotive traffic. Source: Zakysant

Global warming

Solar radiation penetrates the earth through the atmosphere and part of the ultraviolet radiation is filtered by the ozone layer in the stratosphere. When the ozone layer is damaged, more ultraviolet radiation enters and the earth heats up more.

Likewise, when conditions are generated in the atmosphere that prevent the release of heat, a global increase in the earth's temperature occurs.

The so-called greenhouse gases (CO2, methane, NO2, SO2 and CFC-11) can damage the ozone layer or prevent the exit of heat radiation from the Earth. For example, CO2 is responsible for 82% of the increase in the greenhouse effect during the last ten years.

Global warming causes serious environmental imbalances such as the loss of glaciers and polar ice that cause sea level rise. Therefore, floods occur in coastal areas and the temperature regime and ocean currents are altered.

On the other hand, the damage to the ozone layer allows more ultraviolet radiation to penetrate the Earth. This type of radiation causes mutations and affects the health of living beings.

Respiratory diseases

According to the World Health Organization (WHO) by 2016 more than 90% of the world's population lived in places with low air quality. The WHO indicates that air pollution is the cause of 7 million deaths annually worldwide.

Diseases caused by air pollution include chronic obstructions, lung cancer, ischemic heart disease, and strokes.

Acid rain

Emissions of CO2, NO2 and SO2 from industrial activities, the use of heating, forest fires and automotive traffic are promoters of acid rain. These gases undergo oxidation processes in the atmosphere and end up forming acids that mix with the water vapor and precipitate.

Acid rain affects natural flora and fauna, crops, human health and even buildings.

Main pollutants

-Gaseous

Carbon monoxide and dioxide (CO and CO2

These gases destroy stratospheric ozone and contribute to the formation of ground-level ozone that forms fogs and promotes the greenhouse effect. On the other hand, when they come into contact with moisture, they form nitric acid which precipitates and forms acid rain.

Nitrogen oxide emissions into the atmosphere come from natural sources around 60% and from anthropic sources 40%. These sources include the oceans, soils, biomass burning, fertilizer use, and various industrial processes.

In 2017, the atmospheric concentration of N2 oxides was 329.9 ppm, which represents 122% of its level in the pre-industrial era.

Sulfur dioxide (SO2)

This gas is a precursor to acid rain and also generates particles of different sizes that are incorporated into the air. These particles can be PM10 (suspended particles of 10 μm or less) and PM2.5 (suspended particles of 2.5 μm or less).

The main source of sulfur dioxide is the burning of fossil fuels, especially coal.

Ground-level ozone (O3) or ground level ozone

Ozone is strongly oxidizing and causes serious damage to human health, other animals and vegetation (including crops). Additionally, it contributes to the greenhouse effect due to the fact that it forms dense fogs.

The accumulation of ozone in the troposphere is due to photochemical reactions that occur in the presence of polluting gases. These gases are generated mainly by automotive transportation and industries.

Methane

Methane (CH4) is the second most important long-lived greenhouse gas. It is estimated that its contribution to generating this environmental condition is approximately 17%.

It is considered that approximately 40% of the methane present in the atmosphere comes from natural sources. Human activities (rice cultivation, ruminant livestock, garbage dumps, fossil fuels) are responsible for the other 60%.

Atmospheric CH4 reached a maximum of 1,859 ppm in 2017, so it is currently at 257% of its pre-industrial level.

Volatile Organic Compounds (VOCs)

Volatile Organic Compounds are chemical substances that contain carbon and that when reacting with nitrogen oxides form O3. Some examples of VOCs are benzene, formaldehyde, and solvents, such as toluene and xylene, among others.

CFC-11

CFC-11 (trichlorofluoromethane) is a powerful greenhouse gas that depletes stratospheric ozone and is regulated under the Montreal Protocol. Since the signing of said protocol for the protection of the ozone layer, it had been possible to reduce CFC-11 emissions.

However, in recent years some countries such as China have increased the production of this gas. Therefore, the reduction rate of CFC-11 in the atmosphere has been decreasing.

Dioxins and furans

These compounds are generated by combustion processes that involve chlorine, being very dangerous pollutants for health. They can be generated both by natural processes and by human activity (for example: industrial activity and burning of garbage).

One of the main sources of generation of these pollutants is the burning of solid waste. In this sense, the massive presence of plastics and synthetic fibers in modern garbage is particularly serious.

-Material particles (PM)

Origin

The material particles come from different sources such as combustion engines, solid fuel and smoke from the burning of fuels. Other sources include mining, foundries, the textile industry, and waste incineration.

Likewise, they can be generated from natural events such as sandstorms and volcanic eruptions.

Classification

To classify the polluting particles, the size is used, among which we have PM10, those whose diameter is equal to or less than 10 μm (0.01 mm). PM2.5 are "fine particles" (diameter 2.5 µm or less) and "ultrafine particles" or PM0.1 have a diameter of 0.1 µm or less.

Effects edit

The fine and ultrafine particles penetrate deep into the lungs causing serious inflammatory disorders. PM0.1 can enter the bloodstream causing intravascular coagulation, anemia, and even leukemia.

Air pollution data in Mexico, Colombia, Venezuela, Peru, Argentina

Air pollution in Mexico City (Mexico). Source: Lidia Lopez

According to the World Air Quality Report (2018), Latin America presents moderate levels of air pollution in concentration of PM2.5 (μg / m³) in its urban areas.

The moderate level implies that sensitive individuals should avoid outdoor activity as they may experience respiratory symptoms.

Mexico

Mexico is one of the 10 countries that emits the highest amount of greenhouse gases into the atmosphere. During 1992 Mexico City was considered the city with the highest air pollution in the world.

Among the causes of this high pollution are the physiography and climate of the city combined with high automobile traffic and industrial activity. During the years 2002 and 2005 the WHO declared Mexico City as the second in concentrations of nitrogen dioxide.

However, the country has made a great effort to reduce this pollution and its indicators have been improving. For the year 2018, it was the third in Latin America with the worst air quality (at a moderate level), surpassed by Santiago de Chile and Lima.

Currently, Mexico is ranked 33 on the World Air Quality Report list that includes 73 countries. This index is based on the concentrations of PM2.5 (μg / m³) present in the air in different regions of the world.

On the other hand, it ranks third among the countries with the most polluted air in Latin America. In addition, five cities in this country are among the 15 with the highest levels of air pollution in the region.

Colombia

The main cause of air pollution in this country is the burning of fossil fuels. Colombia is ranked 50th in the World Air Quality Report (2018) and ranks fifth in Latin America in concentrations of PM2.5 (μg / m³).

In general terms, the levels of nitrogen oxides and sulfur remain within the permissible ranges. For its part, ground level ozone exceeds critical levels in urban areas.

Venezuela

It has been pointed out that air pollution in the main urban centers of the country has increased due to automobile traffic. On the other hand, in the oil and petrochemical industry, preventive maintenance plans do not work, causing serious pollution problems.

Regarding the concentration of total suspended particles (PTS) in 2008 they reached 35 µg / m3 in urban areas. On the other hand, PM10 reached 37 µg / m3 in 2009 and by 2010 it exceeded 50 µg / m3.

Peru

As indicated in the World Air Quality Report (2018) Peru is the country with the highest air pollution in Latin America and the 14th in the world.

In Lima the levels of sulfur dioxide and nitrogen as well as suspended particles are above those allowed by the WHO. The main cause of this high pollution is automobile traffic combined with the climatic conditions of the area.

These conditions place Lima as the second capital city with the worst air quality in Latin America (at the moderate level). It is currently only surpassed by Santiago de Chile.

Argentina

In the Buenos Aires metropolitan area, the main problem is motor vehicle traffic, generating critical levels of PM2.5 and carbon monoxide (CO). In the Bahía Blanca area, high levels of SO2, NOx and NH3 are present in the vicinity of the petrochemical pole.

In the city of Mendoza there are thermal inversion events in winter with high levels of ozone (O3) on the surface.

Solutions

Awareness

A key element is to raise awareness among citizens about the seriousness of the problem of air pollution, its causes and consequences. This will allow for the necessary pressure to demand citizen attention to the problem.

In most cases, people do not associate health problems with the quality of the air they breathe.

Legislative action

Strengthen international conventions and agreements aimed at reducing greenhouse gas emissions, such as the Kyoto Protocol. Currently many of the countries that have signed the agreement have not reached the proposed goals.

On the other hand, several industrialized countries with a high emission of greenhouse gases (USA, Russia and Canada) do not follow this international agreement. Therefore, greater international pressure is needed to address this serious problem.

Technological applications

Waste management

It is necessary to orient the problem of waste based on the three Rs of ecology (reduce, reuse and recycle). Otherwise, emissions of gases and particles into the atmosphere will be a growing problem.

Efficiency of industrial processes and use of clean energy sources

Industrial processes must achieve levels of technological efficiency that allow reducing the emission of gases and particles into the atmosphere.

Likewise, the burning of fossil fuels is one of the main sources of polluting gases and particles. Therefore, the use of clean energies such as hydroelectric, solar and geothermal should be promoted.

Transport

One of the main causes of air pollution in large urban centers is automobile traffic. Therefore, the implementation of non-polluting public means of transport should be promoted to reduce the problem.

Forests as a carbon sink

To guarantee an increase in carbon sinks, it is necessary to protect forests and reforest new areas. On the other hand, stimulating the development of green cities contributes to reducing environmental CO2.

In this sense, it should be taken into account that 1,000 kg of wood is equivalent to about 400 to 500 kg of fixed carbon.

References

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