Nowadays, a lot of big cities face the problem of caustic poisonous smog.
The World Health Organization (WHO) says dangerous fog causes serious harm to people and nature. What are the causes and consequences of smog, what varieties are distinguished by ecologists, and how to protect yourself if you cannot move to another city?
The definition of smog: Smog is a mixture of smoke, fog, and some pollutants. This term is a fusion of two words “smoke” and “fog”.
The author of this term is considered to be Dr. Henry Antoine de Vaux. It was he who first described London smog, which contained smoke and sulfur dioxide released into the city air due to the active burning of coal at the beginning of the 20th century.
Even then, studies showed that dense fog with soot particles can cause serious illness and even death.
Despite the fact that environmental requirements have seriously changed since then, standards for emissions and maximum allowable concentrations of a number of substances have been introduced, the problem has persisted.
Let’s look at what smog is and how it is formed. According to the latest WHO data, nine out of ten people breathe polluted air, resulting in more than two million deaths each year from heart disease and more than a million from a stroke.
Reasons for the appearance of smog
This phenomenon occurs when the warm rays of the sun interact with harmful substances in the lower atmosphere. Smog occurs when a combination of four factors: heat, bright sun, lack of wind, traffic jams, and forest fires.
It is calm weather that contributes to the accumulation of harmful particles in a certain area.
Also, the cause may be the so-called temperature inversion – a climatic anomaly in which warm air cannot rise due to pressure from above cold air masses. That is why pollutants cannot leave the place where they were formed.
Typical causes of smog in different cities of the world:
- Heavy vehicle traffic
- Burning coal
- Evaporation from paints and varnishes
- Fires
According to the composition and method of formation of dangerous fog, four varieties are distinguished (smoke from natural fires due to burning forests and peat bogs is not singled out as a special category).
Sulfuric smog
The reason for the formation of London-type smog is a high percentage of sulfur oxides in the air due to the use of coal and other types of fuel for heating homes, and the operation of thermal power plants.
The recycling process also releases soot and other hazardous microparticles.
What causes this type of smog?
The most famous catastrophic consequences were felt by the inhabitants of the capital of Great Britain in 1952. Citizens are accustomed to London-type fog, but due to the excess of sulfur dioxide and exhaust gases in the air, it has turned thick and caustic.
Its density was so high that cars could not move on the street, and actors could not be seen in theaters.
At that time, more than 12 thousand people died in England, and another 100 thousand were diagnosed with respiratory diseases, the consequences of the Great Smog for animals and plants are not known for certain.
Volcanic smog, or vogue
Appears during a volcanic eruption.
After the interaction of impurities with sunlight, oxygen, and water vapor, caustic chemicals are formed, this smog is harmful to people (it can cause sore throat, burning, and redness of the mucous membranes) and to all life on Earth.
The population of the Hawaiian Islands, the archipelagos of the state of Vanuatu, etc., periodically suffer from wog.
Ice smog
Rarely seen, mostly in winter in Alaska.
Formed under the following conditions: air temperature below -30 ° C, calm weather, and high humidity.
Various pollutants easily attach to ice crystals formed in the air and remain in suspension. Prolonged exposure to such an environment negatively affects the respiratory system and blood circulation.
Photochemical smog
Los Angeles, or photochemical smog, is the most common type on the planet.
Named after the city that produces daily a large number of nitrogen oxides (over 1000 tons) – Los Angeles has a developed road network and millions of cars. The research has calculated that city residents are stuck in traffic jams for 104 hours.
Brownish haze is formed due to the effect of the sun, hydrocarbons, and nitrogen oxides. Favorable conditions for the formation of photochemical smog are created in most large cities with high car traffic.
Impact on people and nature
The main problems of the smog are not related to the deterioration of visibility and difficulties in the process of moving around the city.
The impact of smog on human health is enormous.
In some cases, everything ends with irritation of the eyes, perspiration, and possible inflammation of the mucous membranes of the nose or larynx, then in other situations, it can provoke an exacerbation of chronic diseases, lung cancer, and even premature death.
The higher the volume of toxic substances and the longer the fog keeps over the city, the more dangerous the consequences. Depending on what the smog consists of and its type, asthma and bronchitis can develop, the protective functions of the body decrease, the risk of colds increases, etc.
The following are at increased risk:
- children
- elderly and patients with respiratory diseases
- people with hypersensitivity
The negative impact of pollutants is felt not only by people. The soil is oxidized, which disturbs the natural bio balance, and some of the metals in it are released, having a negative effect on plant roots and groundwater.
Ozone stops the growth and development of plants and reduces crop yields. Also, the consequences, regardless of what caused the smog (exhaust from cars, low temperatures, volcanic activity, or combustion), include the appearance of corrosion of buildings and cars.
A study by the Clean Air Foundation (a philanthropic foundation tackling global air pollution) showed that exceeding PM10 concentrations also has a negative impact on the economy: consumer spending is reduced by 20 million euros.