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The danger of urban air: ancient theories and modernity
The danger of urban air: ancient theories and modernity

According to the WHO, nine out of ten people on the planet breathe air with a high concentration of pollutants. Microscopic pollutants can pass through our body's defense systems and cause a variety of diseases that claim about seven million lives every year. The fact that air not only gives life, but also harms it, mankind thought back in ancient times. This knowledge migrated to the Middle Ages, and with the development of industry and science, it acquired a new reading.

Probably, each of us at least once in our life, leaving the house on the street, felt that something was wrong with the air: either the smell of exhaust gases, or garbage, or burning.

All this, of course, gives us some inconvenience, but as soon as we stop feeling annoying aromas, we think that now it is quite safe to breathe deeply. However, the absence of visible smog and unpleasant odors does not mean at all that the air around is safe, “healthy”.

Harmful fog is like deception

In the XIV-XIX centuries, the theory of miasms became widespread (ancient Greek μίασμα - "pollution", "filth"). Now this may seem ridiculous, but the doctors of that time assumed that epidemics were caused by "infectious elements" living in the atmosphere, the nature of which was not known. It was believed that miasms (harmful vapors) emanate from the centers of their formation (swamp water, waste products, decaying animal corpses in the soil, etc.), penetrate into the air, and from there - into the human body, causing destructive consequences in it.

The theory of miasms came from ancient Greece - Hippocrates himself believed that pestilence or illness could be caused by "bad" air and unpleasant odors. This idea was supported by other Greek doctors - for example, Galen was opposed to the construction of cities near swamps, because he believed that their fumes infect people.

The miasma theory later spread throughout Europe. In the XIV-XV centuries, plague pandemics increased interest in medicine, and especially inquisitive medical workers began to study the works of ancient Greek scientists. So miasms took root in the minds of people for several centuries and became an explanation for the occurrence of serious diseases.

In the 16th century, European doctors went even further and hypothesized that miasms caused disease in those who risked their health more often, such as those who like to take baths. According to medieval doctors, washing the body, widening the pores, greatly facilitated the penetration of miasms into the body. As a result, the opinion has spread among the population that washing is harmful.

The philosopher Erasmus of Rotterdam wrote: "There is nothing more dangerous than when many expose themselves to the action of the same vapor, especially when their bodies are exposed to heat." It seemed logical to people that if diseases are carried through the air in the form of the smallest particles from decomposed substances, then the steam accelerates the process of infection. The fact that high temperatures kill microbes, no one knew yet, as well as about the microbes themselves.

The "miasmatic" idea quickly took root in cities where there was a terrible unsanitary condition, and unpleasant odors prevailed. It is the stench that has become the hallmark of the miasma theory. People believed that epidemics were caused by stench. The image of a thick, poisonous cloud, bringing death when inhaled, increasingly appeared in the works of illustrators and caused real hysteria: the townspeople began to fear not only fog, but even the night air, so the windows and doors were tightly locked before going to bed.

Diseases caused by miasms included plague, typhoid fever, cholera, and malaria.The church and government tried to save themselves from the "black death" by purifying the air with the help of incense. Even in the masks of plague doctors, the end of the beak was filled with odorous herbs, which supposedly helped not to get infected.

China also fell victim to the miasmatic theory. Here it was believed that diseases were caused by humid, "dead" air coming from the South China Mountains. The fear of the South China swamps has deeply influenced China's society and history. The government often expelled criminals and other people guilty of the authorities to these lands. Few moved there on their own, so the development of South China was suspended for many years.

In the middle of the 19th century, malaria crippled Italy and claimed about 20 thousand lives annually. Even the very name of the disease is a direct reference to its "miasmatic" origin - in the Middle Ages, the Italian malo meant "bad" (+ aria, "air").

Around the same time, England and France faced a massive outbreak of cholera. The peak of the crisis was the summer of 1858, which went down in history as the Great Stench. Hot weather for London, lack of sewage and systematic waste collection led to the pollution of the Thames, where for many years the contents of chamber pots, spoiled food and even dead bodies fell (the granite embankment of the river had not yet been built and people often drowned there).

The city smelled of rot and filth, everyone was frightened by the stench that reigned everywhere. In addition, the Thames and the rivers adjacent to it served as a source of drinking water for the townspeople, so "summer diarrhea" (typhoid fever) was common among Londoners, and cholera continued to claim thousands of lives. Then it never occurred to anyone to boil water, everyone drank it raw.

But it was precisely this climax of human suffering that spurred decisive action: the city's utilities began the greatest engineering project of the time. Under the leadership of Joseph Baseljet, a sewage system was created over the next six years, separating waste from the main water supply and diverting it elsewhere.

The contents of the sewer were collected in huge reservoirs east of London and dumped into the sea at low tide. This principle of operation of the sewage system made it possible for a long time to do without treatment facilities, the construction of which was attended only in the 20th century. The last cholera outbreak occurred in London in the 1860s, and over time, the Great Stench became only a distant memory.

Thus, the miasms influenced a qualitative leap in the standard of living of Londoners, and then of Europeans. Of course, with the discovery of microorganisms at the end of the 19th century, it became clear that diseases were not caused by "harmful" air.

The path to refuting the theory of miasms was long, and it was started by the anatomist Filippo Pacini, who researched the cholera pandemic in London. In 1854, he discovered the bacteria Vibrio cholerae (Vibrio cholerae) in dirty water, but then no one believed him - people explained the outbreak that had stopped for a while by the loss of smell among the population after an attempt by government services to cleanse the city with strong chemicals.

Refutations were also put forward by the British physician John Snow, who conducted experiments and saw that the cells of cholera (a disease unknown at the time) divide and multiply their species, just like animal or plant matter. Then, in 1857, Louis Pasteur showed that fermentation is based on the growth of microorganisms, and in 1865 he introduced the scientific community to his now famous theory, according to which diseases are caused by the violent activity of bacteria. In 1883, Robert Koch dealt a crushing blow to the miasms, after which the term became hopelessly outdated. The scientist proved the microbial basis of tuberculosis, anthrax and cholera.

Now, thanks to these scientific discoveries, we know that malaria is spread by mosquitoes, bubonic plague by sick fleas on rats, and cholera lives in polluted water bodies.

The country needs steam locomotives …

Despite numerous epidemics, the industrial revolution of the 18th-19th centuries did take place. The world learned about the hidden potential of coal, the chemical industry began to develop, and this could not but affect the environment. If at first the thought of industrial pollutants did not occur to anyone, then by the middle of the 20th century it became obvious that in economically developed regions - Europe, North America and Japan - air quality is noticeably deteriorating and now actually causes harm to human health.

Literally a century later, in 1952, another tragedy will happen in London, which will be worse than the cholera epidemic. This event went down in history as the Great Smog: a poisonous fog enveloped the city and paralyzed it for four days. Winter came early that year, so coal-fired power plants were operating at full capacity, people fired fireplaces in their homes - also with the help of coal.

Moreover, "good" coal in the post-war crisis was exported, and for home use in the country they used cheaper raw materials with sulfur impurities, which led to the formation of a particularly pungent smoke. By the way, in those years, city trams were actively replaced by buses with diesel engines.

Los Angeles smog

On December 4, London fell into the anticyclone action zone: stagnant cold air was under the "cover" of warm air (the effect of temperature inversion). As a result, on December 5, a cold fog descended on the British capital, which could not dissipate. Inside it accumulated no outlet exhaust gases, factory emissions, soot particles from hundreds of thousands of fireplaces.

As you know, fogs are not uncommon for London, so at first residents did not attach much importance to this phenomenon, but already on the first day, mass visits to hospitals began with complaints of a sore throat. The smog dispersed on December 9 and, according to the first statistics, about 4,000 people became its victims. For several months, the death toll was 12 thousand, and various respiratory diseases associated with the consequences of the Great Smog, were found in 100 thousand people.

It was an unprecedented environmental disaster, after which the active development of environmental legislation began in England, and the world began to seriously think about regulating emissions.

But the London catastrophe was not the only one. Before her in the American city of Donor on October 27-31, 1948, a similar situation occurred. As a result of the temperature inversion, soot began to fall out from the mixture of fog, smoke and soot, which covered houses, sidewalks and pavements with a black blanket. For two days the visibility was so bad that the residents could hardly find their way home.

Soon, doctors began to be besieged by coughing and choking patients who complained of lack of air, runny nose, pain in the eyes, sore throat and nausea. Over the next four days, until the heavy rain began, 5910 people out of 14 thousand residents of the city fell ill. In the first days, 20 people died from respiratory complications, and another 50 died within a month. Many dogs, cats and birds also died.

Researchers, after analyzing the events, blamed the U.S. zinc plant for the emissions of hydrogen fluoride and sulfur dioxide, which destroyed almost all vegetation within a half-mile radius. Steel's Donora Zinc Works.

In America, problems with air pollution have arisen more and more over the years. According to studies from the 1960s and 1970s, the air over much of the eastern part of the country was chronically polluted, especially in cities such as Chicago, St. Louis, Philadelphia, and New York. On the west coast, Los Angeles suffered the most from air pollution.

In 1953, a six-day smog in New York caused about 200 deaths, in 1963 a thick fog with soot and smoke claimed the lives of 400 people, and in 1966, due to the repeated temperature inversion, 170 residents of the city died.

Los Angeles began to suffer severely from air pollution in the 1930s, but here the smog was different: dry fog occurred on hot days. This is a photochemical phenomenon: haze is formed when sunlight reacts with hydrocarbon emissions (from petroleum combustion) and car exhaust.

Since then, smogs have been classified into two main types - "London" and "Los Angeles". Smogs of the first type arise in moderately humid climates during the transitional and winter seasons in large industrial cities in the absence of wind and temperature inversion. The second type is characteristic of the subtropics and appears in summer in calm weather with intense exposure to solar radiation on the air oversaturated with transport and factory emissions.

The death of people from dirty air occurred not only due to obvious man-made disasters and a booming industry, but also due to natural anomalies and irrational land use.

The strangest and most unexpected was the story that took place in African Cameroon on Lake Nyos, from the waters of which in 1986 a huge amount of carbon dioxide escaped, which killed all living things around, including 2,000 local people. But such natural cases of carbon poisoning are rather an exception, because by the end of the 20th century, people were more suffering from their own unreasonable actions in the field of handling agricultural land and forest areas.

The Indonesian fires of 1997-1998, including Singapore, Malaysia, Thailand, Vietnam and Brunei, were the worst on record at that time. During this period, industrial logging intensified in the country, and peat bogs and swamps were drained for planting oil palm and rice. Indonesian forests have always been resistant to burning, even when people practiced slash-and-burn agriculture, but now they are vulnerable to fires during drought.

Sulfides, nitrous oxides and ash emitted from incineration combined with industrial pollution have created a choking haze that has raised the concentration of pollutants in the air to unprecedented heights. Then more than 200,000 residents were hospitalized with cardiovascular and respiratory diseases, 240 people died.

The fires have also had a long-term impact on the health of the 70 million people in Southeast Asia. According to a study by a group of scientists from Australia, the USA and Canada, the highest mortality caused by smoke from fires in natural areas for the period from 1997 to 2006 was recorded in Southeast Asia (110 thousand people per year) and Africa (157 thousand people in year).

The authors note that the main damaging factor is particles with a diameter of less than 2.5 microns, consisting of carbon and organic matter. In addition to literally killing people, the fires affected the economies of countries, destroyed protected natural areas, nature reserves, rainforests and reduced biodiversity.

The trend towards transferring production capacity from developed to developing countries dates back to the 1960s. While developed countries, taught by bitter experience, introduced new policies aimed at controlling emissions and caring for the environment, in China, India, Asia and Latin America, volumes of harmful production grew. By the 1990s, oil refining enterprises moved here, the pulp and paper, rubber, leather, chemical industries began to develop, the extraction of non-metallic minerals began, as well as work with iron, steel and other metals.

Mud above your head is more dangerous than mud under your feet

Already in the first decade of the XXI century, it became obvious that environmental pollution in countries - industrial giants has an impact on the whole world.

In the race for economic growth in the early 2000s, the Chinese government was completely oblivious to the environmental impact of its many industries. As a result, by 2007, China surpassed the United States in terms of greenhouse gas emissions and still occupies a leading position in CO2 production. Poor air quality in China causes 1.6 million deaths a year, according to a 2015 study by the non-profit organization Berkeley Earth.

And it's not just China that suffers - according to the State of Global Air report, India, Pakistan, Indonesia, Bangladesh, Nigeria, the United States, Russia, Brazil and the Philippines are among the top 10 countries with the highest deaths due to air pollution.

In 2015, air pollution caused about 8.8 million premature deaths worldwide. And in a study recently published by the scientific publication Cardiovascular Research, it is said that due to air pollution, life expectancy per capita has decreased by 2.9 years on average, mainly due to the development of cardiovascular diseases. For comparison: smoking reduces the same life expectancy by 2, 2 years, and diseases such as HIV and AIDS - by 0, 7 years.

According to the authors of the work, if we reduce harmful emissions of fossil fuels into the atmosphere right now, then life expectancy can increase by 2 years.

The idea that elevated levels of air pollution affect not only the respiratory system, but also increase the risk of attacks, heart attacks and other cardiovascular diseases, was confirmed back in 2010 by the American Heart Association. According to a group of experts who analyzed data from epidemiological, toxicological and other medical studies for the period from 2004 to 2010, this risk is most strongly increased by air pollution with fine aerosol particles up to 2.5 microns in size. Emissions of these particles mainly come from transport, power plants, burning of fossil fuels, and forest fires.

Tiananmen Square Beijing China

Later it turned out that not only the heart and lungs, but also the brain were hit. In the experiment, about 20,000 people in China regularly took tests in mathematics and languages ​​over four years. In the places where the test subjects lived, measurements were made of the level of sulfur dioxide, nitrogen and particles less than 10 microns in size in the air. According to the final data, it turned out that air pollution negatively affects the cognitive abilities of mature men and people with a low level of education. Also, the population living in an unfavorable air environment increases the risk of degenerative diseases (Alzheimer's and other forms of dementia).

In 2018, a group of scientists specializing in respiratory diseases published a conclusion that air pollution can potentially harm all organs of the human body, as tiny pollutants enter the bloodstream with inhalation and affect the functioning of many body systems. This leads to the risk of developing completely different diseases - from diabetes to miscarriages and premature birth.

The researchers learned about the long-term impact of air pollution on public health when they undertook to analyze the consequences of the Great Smog 60 years after the incident. Volunteers - 2,916 people - filled out questionnaires and indicated the presence of pulmonary diseases in childhood and adulthood. The responses were compared with those of people born in 1945-1955 outside London or who were exposed to smog later. It turned out that those whom the Great could find in the womb or at the age of one year were more likely to get asthma - by 8% and 9.5%, respectively.

One of the authors of the study, Matthew Nadell, also argues that the work done is relevant not only for London in the mid-20th century.“The results show that the health of young children living in highly polluted areas such as Beijing is likely to change significantly over the course of their lives,” he concludes.

As for Russia, more than 70 million people are affected by the increased concentrations of suspended particles in the air, i.e. almost every second resident of the country, write the authors of the book "Basics of assessing the impact of a polluted environment on human health" B. A. Revich, S. A. Avaliani and P. I. Tikhonova. Suspended substances are nitrogen and sulfur dioxides, carbon monoxide. Most of these substances are irritating and negatively affect the state of the respiratory system.

Also in the air of some cities in our country there are such specific inorganic substances as copper, mercury, lead, hydrogen sulfide, carbon disulfide and fluoride compounds. Air pollution in Russian cities leads to an increase in the incidence of children (pharyngitis, conjunctivitis, bronchitis, bronchial asthma, etc.), changes in the functions of external respiration in adults and additional mortality of about 40,000 people per year.

The unfavorable environmental situation also harms the economies of many countries - losses due to the loss of labor, treatment of diseases and insurance payments amount to about $ 4.6 trillion a year, or 6% of world GDP, according to the medical journal "Lancet". The study also says more people die each year from air, water and soil pollution than from obesity, excessive alcohol consumption, car accidents or high sodium levels in food.

And, of course, polluted air has a huge impact on the planet's climate. The harm from global warming, like the warming itself, did not want to be taken seriously for a long time. However, it is difficult to argue with the unprecedented increase in the concentration of carbon dioxide in the atmosphere - recently the concentration exceeded 413 parts per million for the first time in the last 650 thousand years. If in 1910 the CO2 content in the atmosphere was about 300 parts per million, then over the last century the figure has increased by more than 100 parts per million.

The reason for the growth was the same burning of fossil fuels and the deforestation of significant tracts of forests, in particular for the expansion of agricultural land and urban areas. Experts and scientists in many studies note that the transition to cleaner energy sources should significantly improve the health of the population and the ecological state of the planet.

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