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10 Biggest Causes Of Air Pollution

• by Staff Writers

The World Health Organization defines air pollution as the alteration of the natural characteristics of the atmosphere caused by biological and chemical contaminants. Air pollution is known to pose a major health risk, as it can lead to the development of respiratory conditions, heart problems, and even cancer.

Unknown to many people, their daily routine activities at home and at work contribute to the worsening of air pollution. If you want to help the environment recover from air pollution, then here is a list of the ten biggest causes of air pollution.  Take a look at this list and see if there is anything you can do to help the environment.

1. Exhaust from Combustion Engines

(Photo courtesy: Wikipedia)

While modes of transportation such as cars, ships and planes have made people’s lives easier, they are also some of the biggest causes of air pollution. Emissions from vehicular combustion engines contain gaseous oxide, nitrous oxide and carbon monoxide, all of which contribute to the depletion of the ozone layer. With a thinner ozone layer, the earth will gradually succumb to sweltering heat.

The melting of the polar ice caps and the rise of sea levels are just some of the jeopardizing effects of air pollution-induced global warming. Apart from environmental damage, air pollution also causes a variety of illnesses such as impaired vision, reduced brain function, lung cancer, and in some cases, death.

2. Use of Coal and Fossil Fuels

(Photo courtesy: Wikipedia)

Factories, power-generating establishments, offices, even homes, utilize fossil fuels and coals for power or heat. Even though beneficial, coal and fossil fuels contribute to air pollution and smog. They also damage structures and hasten the oxidation of iron. Add to that, they can cause harm on plants, which significantly reduces oxygen supply on earth.

3. Petroleum

(Photo courtesy: Wikipedia)

Petroleum is the driving force behind vehicles, however, this helpfulsubstance is a major contributor to global air pollution. Petroleum releases carbon dioxide and nitrous oxide into the air, which, when inhaled, can lead to illnesses.

It also contains hydrocarbons, which bind to nitrous oxide in the presence of sunlight to create ozone. While the ozone layer technically protects the earth from the ultraviolet rays of the sun, it also gives way to the production of smog, which is the leading cause of a variety of lung problems.

4. Mining Operations

(Photo courtesy: Wikipedia)

Operations, like mining and truck traffic, are some of the top causes of air pollution. These activities release carbon monoxide, sulfur dioxide and nitrous oxide into the air, all of which contribute to development of smog and various health problems. Apart from these emissions, gold mines also release mercury particulates to the atmosphere. In excess amounts, mercury inhalation can lead to sensation disturbances, muscle weakness, respiratory problems, certain cancers, even death.

5. Stationary Sources: Plants and Mills

(Photo credit: Explorer Björn | Flickr)

On the process of generating their products, paper mills, steel mills, iron mills, cement plants and asphalt plants release aerosols, particulates, gases and vapors into the air. These mills and plants, also known asstationary sources, yield ammonia, sulfur oxide, hydrogen chloride and hydrogen sulfide, to name a few.

Fortunately, these air pollution causes have managed to reduce their emissions with the use of control devices like carbon adsorbers, fabric fillers, cyclones and electrostatic precipitators, to name a few.

6. Fertilizer Dust

(Photo credit: Henry Work | Flickr)

Fertilizers are useful for farmers as they accelerate the growth of crops and plants. Nonetheless, the accumulation of fertilizer dust (even those made from organic ingredients) can give way to the production of ammonia and nitrogen oxide, both of which contribute to global warming and harmful acid rain. Such pollution also yields methane, a greenhouse gas. With the presence of high amounts of methane in the atmosphere, the heat that should have been radiated back to the atmosphere are bounced back to earth, keeping the earth insulated.

7. Chemical Pesticides

(Photo courtesy: Wikipedia)

Pesticides are very helpful for farmers as they keep vermin, bacteria, and fungi that destroy their crops at bay. However, use of pesticides, especially those made from chemicals, also wreaks air pollution. Air pollution caused by pesticides can be fatal for animal, birds, even marine life, especially if the emissions already infiltrate their food sources.

Apart from its contributory effects on air pollution, pesticides actually damage plant health in the long run. Incessant use of chemical pesticidesleads to decreased plant production and pollination, which then results in lower crop yields.

 8. Power Lines

(Photo credit: FullyFunctnlPhil | Flickr)

Just because power lines don’t emit visible smoke, it does not mean that they are not among the causes of air pollution. In fact, high voltage lines, especially those located near polluted cities, attract air that contains harmful particulates. The electricity running through the lines results in the charging or the ionization of the air.

When inhaled by humans, ionized air significantly increases the level free radicals in the body. These free radicals in the body bring about tissue damage, aging, even the development of certain cancers.

9.  Radioactive Fallout

((Photo credit: dreamlandresort.com)

Radioactive sources yield high amounts of energy, as well as harmful quantities of sulfur dioxide and several heavy metals into the air. In highly-industrialized cities, air pollution from radioactive fallout have been proven to create numerous environmental concerns, such as defoliation, deformation and undergrowth damage in trees, to name a few.

Apart from its impact on the environment,  radioactive air pollution also endangers human health. Perhaps the most infamous case of radioactive fallout is that of Chernobyl in Ukraine, wherein the survivors of the nuclear meltdown developed cancers and a variety of respiratory ailments after inhaling emissions coming from the nuclear plant.

10. Indoor Air Pollution

(Photo credit: nirvana168 | Flickr)

Outdoor air pollution causes contribute to a number of contaminants in the atmosphere. It should be noted though that indoor air pollution also plays a major role in the worsening air quality around the world.

Urban infrastructures are usually afflicted with a condition called “Sick Building Syndrome.” In this case, fumes from household chemicals, paint, and other substances get trapped in the building because of the lack of ventilation. These fumes can cause a variety of health problems for its homeowners, tenants, or visitors.

While technological advancements have paved the way for innovations in transportation, agriculture, and energy production, the fact of the matter is they have become the biggest causes of air pollution. Hopefully, knowing about these top ten causes can motivate you to make a move to contribute for a cleaner, safer air.

Cities[edit]

Nitrogen dioxide concentrations as measured from satellite 2002-2004

Deaths from air pollution in 2004

Air pollution is usually concentrated in densely populated metropolitan areas, especially in developing countries where environmental regulations are relatively lax or nonexistent^{[citation needed]}. However, even populated areas in developed countries attain unhealthy levels of pollution with Los Angeles andRome being two good examples.^[53]

NATA[edit]

The National-Scale Air Toxics Assessment (NATA) is EPA's ongoing comprehensive evaluation of air toxics in the U.S. EPA developed the NATA as a state-of-the-science screening tool for State/Local/Tribal Agencies to prioritize pollutants, emission sources and locations of interest for further study in order to gain a better understanding of risks. NATA assessments do not incorporate refined information about emission sources, but rather, use general information about sources to develop estimates of risks which are more likely to overestimate impacts than underestimate them. NATA provides estimates of the risk of cancer and other serious health effects from breathing (inhaling) air toxics in order to inform both national and more localized efforts to identify and prioritize air toxics, emission source types and locations which are of greatest potential concern in terms of contributing to population risk. This in turn helps air pollution experts focus limited analytical resources on areas and or populations where the potential for health risks are highest. Assessments include estimates of cancer and non-cancer health effects based on chronic exposure from outdoor sources, including assessments of non-cancer health effects for Diesel Particulate Matter (PM). Assessments provide a snapshot of the outdoor air quality and the risks to human health that would result if air toxic emissions levels remained unchanged.^[54]

Most Polluted World Cities by PM[55]
Particulate matter, μg/m³ (2004)	City
168	Cairo, Egypt
150	Delhi, India
128	Kolkata, India (Calcutta)
125	Tianjin, China
123	Chongqing, China
109	Kanpur, India
109	Lucknow, India
104	Jakarta, Indonesia
101	Shenyang, China

Governing urban air pollution – a regional example (London)[edit]

In Europe, Council Directive 96/62/EC on ambient air quality assessment and management provides a common strategy against which member states can "set objectives for ambient air quality in order to avoid, prevent or reduce harmful effects on human health and the environment . . . and improve air quality where it is unsatisfactory".^[56]

On 25 July 2008 in the case Dieter Janecek v Freistaat Bayern CURIA, the European Court of Justice ruled that under this directive^[56] citizens have the right to require national authorities to implement a short term action plan that aims to maintain or achieve compliance to air quality limit values.^[57]

This important case law appears to confirm the role of the EC as centralised regulator to European nation-states as regards air pollution control. It places a supranational legal obligation on the UK to protect its citizens from dangerous levels of air pollution, furthermore superseding national interests with those of the citizen.

In 2010, the European Commission (EC) threatened the UK with legal action against the successive breaching of PM10 limit values.^[58] The UK government has identified that if fines are imposed, they could cost the nation upwards of £300 million per year.^[59]

In March 2011, the City of London remains the only UK region in breach of the EC’s limit values, and has been given 3 months to implement an emergency action plan aimed at meeting the EU Air Quality Directive.^[60] The City of London has dangerous levels of PM10 concentrations, estimated to cause 3000 deaths per year within the city.^[61] As well as the threat of EU fines, in 2010 it was threatened with legal action for scrapping the western congestion charge zone, which is claimed to have led to an increase in air pollution levels.^[62]

In response to these charges, Boris Johnson, Mayor of London, has criticised the current need for European cities to communicate with Europe through their nation state’s central government, arguing that in future "A great city like London" should be permitted to bypass its government and deal directly with the European Commission regarding its air quality action plan.^[60]

In part, this is an attempt to divert blame away from the Mayor's office, but it can also be interpreted as recognition that cities can transcend the traditional national government organisational hierarchy and develop solutions to air pollution using global governance networks, for example through transnational relations. Transnational relations include but are not exclusive to national governments and intergovernmental organisations ^[63] allowing sub-national actors including cities and regions to partake in air pollution control as independent actors.

Particularly promising at present are global city partnerships.^[64] These can be built into networks, for example the C40 network, of which London is a member. The C40 is a public ‘non-state’ network of the world’s leading cities that aims to curb their greenhouse emissions.^[64] The C40 has been identified as ‘governance from the middle’ and is an alternative to intergovernmental policy.^[65] It has the potential to improve urban air quality as participating cities "exchange information, learn from best practices and consequently mitigate carbon dioxide emissions independently from national government decisions".^[64] A criticism of the C40 network is that its exclusive nature limits influence to participating cities and risks drawing resources away from less powerful city and regional actors.

Atmospheric dispersion[edit]

Main article: Atmospheric dispersion modeling

The basic technology for analyzing air pollution is through the use of a variety of mathematical models for predicting the transport of air pollutants in the lower atmosphere. The principal methodologies are:

• Point source dispersion, used for industrial sources.
• Line source dispersion, used for airport and roadway air dispersion modeling
• Area source dispersion, used for forest fires or duststorms
• Photochemical models, used to analyze reactive pollutants that form smog

Visualization of a buoyant Gaussian air pollution dispersion plume as used in many atmospheric dispersion models.^[66]

The point source problem is the best understood, since it involves simpler mathematics and has been studied for a long period of time, dating back to about the year 1900. It uses a Gaussiandispersion model for continuous buoyant pollution plumes to predict the air pollution isopleths, with consideration given to wind velocity, stack height, emission rate and stability class (a measure of atmosphericturbulence).^[66][67] This model has been extensively validated and calibrated with experimental data for all sorts of atmospheric conditions.

The roadway air dispersion model was developed starting in the late 1950s and early 1960s in response to requirements of the National Environmental Policy Act and the U.S. Department of Transportation (then known as the Federal Highway Administration) to understand impacts of proposed new highways upon air quality, especially in urban areas. Several research groups were active in this model development, among which were: the Environmental Research and Technology (ERT) group in Lexington, Massachusetts, the ESL Inc. group in Sunnyvale,California and the California Air Resources Board group in Sacramento, California. The research of the ESL group received a boost with a contract award from the United States Environmental Protection Agency to validate a line source model using sulfur hexafluoride as a tracer gas. This program was successful in validating the line source model developed by ESL Inc. Some of the earliest uses of the model were in court cases involving highway air pollution, the Arlington,Virginia portion of Interstate 66 and the New Jersey Turnpike widening project through East Brunswick, New Jersey.

Area source models were developed in 1971 through 1974 by the ERT and ESL groups, but addressed a smaller fraction of total air pollution emissions, so that their use and need was not as widespread as the line source model, which enjoyed hundreds of different applications as early as the 1970s. Similarly photochemical models were developed primarily in the 1960s and 1970s, but their use was more specialized and for regional needs, such as understanding smog formation in Los Angeles, California.

See also[edit]

Air pollutant concentrations Air stagnation ASEAN Agreement on Transboundary Haze Pollution Asian brown cloud Atmospheric chemistry Beehive burner Best Available Control Technology Building biology Critical load Emission standard Emissions & Generation Resource Integrated Database Environmental agreement Flue-gas emissions from fossil-fuel combustion

Global Atmosphere Watch Global dimming Haze Health Effects Institute (HEI) Indicator value Industrial Hygiene Foundation International Agency for Research on Cancer Kyoto Protocol Light water reactor sustainability List of smogs by death toll Lowest Achievable Emissions Rate NASA Clean Air Study Particulate matter sampler Polluter pays principle Regulation of greenhouse gases under the Clean Air Act Tire fire

Global warming portal Environment portal

Control devices[edit]

The following items are commonly used as pollution control devices by industry or transportation devices. They can either destroy contaminants or remove them from an exhaust stream before it is emitted into the atmosphere.

• Particulate control
  • Mechanical collectors (dust cyclones, multicyclones)
  • Electrostatic precipitators An electrostatic precipitator (ESP), or electrostatic air cleaner is a particulate collection device that removes particles from a flowing gas (such as air) using the force of an induced electrostatic charge. Electrostatic precipitators are highly efficient filtration devices that minimally impede the flow of gases through the device, and can easily remove fine particulates such as dust and smoke from the air stream.
  • Baghouses Designed to handle heavy dust loads, a dust collector consists of a blower, dust filter, a filter-cleaning system, and a dust receptacle or dust removal system (distinguished from air cleaners which utilize disposable filters to remove the dust).

• • Particulate scrubbersWet scrubber is a form of pollution control technology. The term describes a variety of devices that use pollutants from a furnace flue gas or from other gas streams. In a wet scrubber, the polluted gas stream is brought into contact with the scrubbing liquid, by spraying it with the liquid, by forcing it through a pool of liquid, or by some other contact method, so as to remove the pollutants.

• Scrubbers
  • Baffle spray scrubber
  • Cyclonic spray scrubber
  • Ejector venturi scrubber
  • Mechanically aided scrubber
  • Spray tower
  • Wet scrubber

• NOx control
  • Low NOx burners
  • Selective catalytic reduction (SCR)
  • Selective non-catalytic reduction (SNCR)
  • NOx scrubbers
  • Exhaust gas recirculation
  • Catalytic converter (also for VOC control)

• VOC abatement
  • Adsorption systems, such as activated carbon
  • Flares
  • Thermal oxidizers
  • Catalytic converters
  • Biofilters
  • Absorption (scrubbing)
  • Cryogenic condensers
  • Vapor recovery systems

• Acid Gas/SO₂ control
  • Wet scrubbers
  • Dry scrubbers
  • Flue-gas desulfurization

• Mercury control
  • Sorbent Injection Technology
  • Electro-Catalytic Oxidation (ECO)
  • K-Fuel

• Dioxin and furan control

• Miscellaneous associated equipment
  • Source capturing systems
  • Continuous emissions monitoring systems (CEMS)

Legal regulations[edit]

Smog in Cairo

In general, there are two types of air quality standards. The first class of standards (such as the U.S. National Ambient Air Quality Standards and E.U.Air Quality Directive) set maximum atmospheric concentrations for specific pollutants. Environmental agencies enact regulations which are intended to result in attainment of these target levels. The second class (such as the North American Air Quality Index) take the form of a scale with various thresholds, which is used to communicate to the public the relative risk of outdoor activity. The scale may or may not distinguish between different pollutants.

Canada[edit]

In Canada air pollution and associated health risks are measured with the The Air Quality Health Index or (AQHI). It is a health protection tool used to make decisions to reduce short-term exposure to air pollution by adjusting activity levels during increased levels of air pollution.

The Air Quality Health Index or "AQHI" is a federal program jointly coordinated by Health Canadaand Environment Canada. However, the AQHI program would not be possible without the commitment and support of the provinces, municipalities and NGOs. From air quality monitoring to health risk communication and community engagement, local partners are responsible for the vast majority of work related to AQHI implementation. The AQHI provides a number from 1 to 10+ to indicate the level of health risk associated with local air quality. Occasionally, when the amount of air pollution is abnormally high, the number may exceed 10. The AQHI provides a local air quality current value as well as a local air quality maximums forecast for today, tonight and tomorrow and provides associated health advice.

1

2

3

4

5

6

7

8

9

10

+

Risk:

Low (1-3)

Moderate (4-6)

High (7-10)

Very high (above 10)

As it is now known that even low levels of air pollution can trigger discomfort for the sensitive population, the index has been developed as a continuum: The higher the number, the greater the health risk and need to take precautions. The index describes the level of health risk associated with this number as ‘low’, ‘moderate’, ‘high’ or ‘very high’, and suggests steps that can be taken to reduce exposure.

^[51]

Health Risk	Air Quality Health Index	Health Messages
		At Risk population	General Population
Low	1-3	Enjoy your usual outdoor activities.	Ideal air quality for outdoor activities
Moderate	4-6	Consider reducing or rescheduling strenuous activities outdoors if you are experiencing symptoms.	No need to modify your usual outdoor activities unless you experience symptoms such as coughing and throat irritation.
High	7-10	Reduce or reschedule strenuous activities outdoors. Children and the elderly should also take it easy.	Consider reducing or rescheduling strenuous activities outdoors if you experience symptoms such as coughing and throat irritation.
Very high	Above 10	Avoid strenuous activities outdoors. Children and the elderly should also avoid outdoor physical exertion.	Reduce or reschedule strenuous activities outdoors, especially if you experience symptoms such as coughing and throat irritation.

^[52]

It is measured based on the observed relationship of Nitrogen Dioxide (NO₂), ground-level Ozone (O₃) and particulates (PM_2.5) with mortality from an analysis of several Canadian cities. Significantly, all three of these pollutants can pose health risks, even at low levels of exposure, especially among those with pre-existing health problems.

When developing the AQHI, Health Canada’s original analysis of health effects included five major air pollutants: particulates, ozone, and nitrogen dioxide (NO2), as well as sulfur dioxide (SO₂), and carbon monoxide (CO). The latter two pollutants provided little information in predicting health effects and were removed from the AQHI formulation.

The AQHI does not measure the effects of odour, pollen, dust, heat or humidity.