Major types of pollution include water pollution, Air pollution, land pollution, noise pollution, soil contamination, light pollution, thermal and radioactive contamination, etc. In this article, the healthcare solutions team discusses the answer to this question, “Which type of pollution includes CFCs and smog?” First of all, let’s know about a general introduction.
Air pollution … not just in the air
Whether you’re in a traffic jam, forced to breathe in the exhaust fumes of hundreds of vehicles, watching the black smoke spewed out from factory chimneys or the horizon disappearing hidden by the smog of a hot summer day, air pollution jumps out at us … and at our lungs. But it can be much more insidious .
Air pollution knows no borders. She happily travels beyond countries, continents and seas. Pollutants such as fine particles can travel over thousands of kilometers 1 . Thus, up to 50% of the mercury resulting from human activity that is deposited each year in North America would come from other continents, in particular from coal-fired power stations in China and India 2 . Airborne deposition is now the main source of mercury in lakes, soil and vegetation in Canada
Of course, pollution can reach us through the air we breathe , but also through contact with our skin . The polluted air can contaminate everything with which it comes in contact: fruits and vegetables as well as water and soil and, indirectly, the food products (plants, animals, fish) which will be nourished by it.
Finally, be aware that pollutants in the air in tiny amounts can concentrate as they move up the food chain . For example, if there is mercury in the air, it can settle in water and be absorbed by small fish. As larger fish eat smaller ones, the concentration of mercury increases because this pollutant, said to be persistent, accumulates in living organisms. Finally, when we eat fish contaminated with mercury, we may actually be victims of air pollution!
ABCs of air pollutants
Air pollutants harmful to health are in the form of gases and respirable particles .
Four gases are the main causes of pollution 4,5 :
- ozone (O 3 )
- nitrogen dioxide (NO 2 )
- sulfur dioxide (SO 2 )
- carbon monoxide (CO)
To them are added other chemical pollutants such as heavy metals and volatile organic compounds (VOCs) which include harmful products such as benzene and polycyclic aromatic hydrocarbons (PAHs).
Respirable particles (also called fine or ultrafine particles) refer to a heterogeneous mixture of solid and liquid particles suspended in the air. They are classified into two categories based on their size rather than their composition. The smaller they are, the more toxic they can be because they then penetrate deeper into the respiratory system and can even reach the cardiovascular system . They are commonly called PM, the abbreviation of the English term particulate matter.
- PM 10 (with a diameter less than 10 micrometers). Note that a human hair is 50 to 150 micrometers in diameter.
- Most toxic PM 2.5 (less than 2.5 micrometers).
According to experts, it is relatively difficult to know which particular pollutant may be responsible for a specific health problem 6 . In fact, most of the time, pollutants, regardless of their origin, come in the form of a cocktail made up of many elements that act in synergy . Thus, epidemiological studies often focus on the various harmful effects of “combined” pollution . The intensity of this pollution is generally estimated by evaluating the concentration of one or two of the main pollutants, which then serve as markers, rather than systematically measuring each of the elements.
Pollutants: where are they?
Surface ozone or ozone layer?
Surface ozone is a toxic pollutant . It should not be confused with the famous ozone layer which protects us from the sun’s rays. Ground-level ozone is formed when nitrogen oxides and volatile organic compounds, which come from vehicles and industries, are transformed under the action of sunlight and heat. Ozone, along with respirable particles, is one of the main components of smog that have an adverse effect on health.
The vast majority of pollutants, gases or particles come from the use of fossil fuels (petroleum, natural gas and coal) which alone meet about 80% of the world’s energy needs. These fuels are mainly used for transport , industry, heating and in thermal power plants. They are mainly concentrated in urban areas 7,8 . It should also be noted that in several large cities, wood heating is a very important source of atmospheric pollution
The origin and concentration of pollutants vary from one place to another depending on the density of the population, the type of industry, the environmental standards in force, etc. In the same neighborhood and depending on the time of day or the season, we can also observe significant differences. Thus, pollution rates are often higher near major arterial roads or industries , and high ozone levels are observed almost only in summer. It should also be remembered that ozone can be found up to 800 km further than its point of origin
In the West, of all sources of air pollution, transport (car, truck, heavy goods vehicle, plane, etc.) remains the great champion. In a city like Montreal, for example, it is estimated to be responsible for around 75% of air pollution 10 , including 85% of nitrogen oxide emissions and 43% of volatile organic compounds (VOCs)
Plane equals pollution?
Air pollutants: what are they, where do they come from?Even though their energy efficiency has improved a lot in recent years, planes contribute more to air pollution than other means of transport 12-14 .
On the one hand, they consume more fuel per kilometer and per person than other modes of transport. On the other hand, the fact that they release their harmful gases directly into the upper atmosphere, makes their action even more damaging. And since they consume a lot of fuel during takeoff and landing, short trips are, relatively speaking, the most polluting.
On smaller trips, it is more ecological to take the train or even the car. For transoceanic journeys, we can always offset this emission of atmospheric pollutants by obtaining “carbon credits” from organizations that invest in “green” projects. See Shelter from air pollution? .
Pollution and greenhouse gases: two things
Fossil fuels (petroleum, natural gas, coal) are the main source of air pollutants. They are also the most important generators of greenhouse gases – mainly carbon dioxide (CO 2 ) – which contribute to global warming.
What about smog?
Smog is a yellowish mist, originating from a mixture of atmospheric pollutants (fine particles and ozone) which limits visibility in the atmosphere, according to the definition given by the Quebec Ministry of Sustainable Development, Environment. and Parks 17 . In January and February 2005, Montreal had the longest smog episode in its history: nine consecutive days 18.
The greenhouse gases are however not strictly pollutants. Carbon dioxide is not in any way toxic in itself. It is even essential for the growth of plants, which capture it and use its carbon to constitute their structure (carbon represents about 40% of the dry matter of plants 15 ).
However, by burning large quantities of fossil fuels, we release a lot of carbon dioxide – trapped in the subsoil for thousands of years -, and plants can no longer fix it. Carbon dioxide is then found in excessive concentration in the air. It can be considered a form of pollution, because it contributes to the greenhouse effect which causes global warming.
It should be noted that global warming tends to accentuate the harmful effects on health of “real” atmospheric pollution 16. It is this global warming that the Kyoto Protocol is trying to counter.
What are Chlorofluorocarbons
chlorofluorocarbons Chemical compounds containing chlorine, fluorine and carbon, indicated with the abbreviation CFC. They correspond to hydrocarbons in which all or part of the hydrogen atoms have been replaced by chlorine and fluorine atoms. They are characterized by high chemical and thermal stability, which increases with the fluorine content, are non-flammable and not very toxic.
CFCs had found wide use as propellants for aerosols, as cooling agents, as blowing agents in the preparation of foamed plastics, etc. However, as they were held to be partly responsible for the depletion of the ozone layer present in the stratosphere, international agreements were formulated aimed at banning their production and use ( Montreal Protocol , 1987; extended in 2007 to HCFCs, hydrochlorofluorocarbons). As regards Italy, the l. 179/16 June 1997 set 31 December 2008 as the deadline for the production, use, marketing, import and export of CFCs. From that date, in order to reduce emissions of gases with a high greenhouse effect potential, it was decided that the restrictions on use should also be applied to HFCs (hydrofluorocarbons).
The application of international agreements made it necessary to replace them with other products. For the aerosol packaging, light hydrocarbons are used (butane, isobutane, pentane etc.) which, however, create serious problems due to their great flammability. In the production of flexible expanded resins it has been possible to recover CFCs while for rigid foam resins (where they remain largely imprisoned in the polymeric mass) light hydrocarbons have been used, which are however more flammable and have a lower thermal insulation power than manufactured goods. This led to innovative research: for example, in the production of polyurethane foams, the carbon dioxide generated during the polymer preparation reaction is used as a blowing agent.2 ).
Which type of pollution include CFCs
Most chlorofluorocarbons are released into the atmosphere through refrigerant leaks and the use of aerosols. They have no noteworthy natural sources. Chlorofluorocarbons are chemical compounds composed of carbon, fluorine and chlorine.
At the point of emission, CFCs are stable, non-flammable, non-toxic, odorless and colorless. However, they begin dividing and releasing chlorine atoms as they reach the stratosphere. The highly reactive rouge chlorine atoms break down the ozone layer, which is responsible for preventing the sun’s harmful ultraviolet radiation from reaching the earth’s surface.
Due to their known destructive properties, the production of CFCs was banned in 1995. They have been replaced by ozone-innocent hydrofluorocarbons.
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