New coronaviruses are raging around the world. In the two years and eight months from December 2019, when the first infected person was reported, to August 2022, the cumulative number of deaths was about6.4 million peopleThe number of deaths is much higher than the number of deaths in the previous year. However, there is one cause of death that has surpassed this number in just one year: air pollution. It is air pollution. In fact, it is said to be the world's largest cause of death, with an annual global death toll of approximately6.7 millionIn the United States, air pollution kills more people than any other cause of death. This article explores the where, how, and how much damage air pollution causes, the current situation, countermeasures, and remaining challenges.

Hazy air and a boy wearing a mask in Indonesia (Photo:CIFOR / Flickr [CC BY-NC-ND 2.0])

Contaminants and Health Hazards

First, let us imagine how air pollution causes damage to the human body. It is caused by airborneair pollutantare. These include sulfur oxides, nitrogen oxides, photochemical oxidants, black carbon, and so many others, and their sources, forms, and the damage they cause vary widely. For example.photochemical smogare pollutants that are transformed by sunlight into photochemical oxidants from automobile and factory exhaust gases, and stay in the air like a mist. These pollutants irritate the mucous membranes and can cause irritation of the eyes and respiratory tract, and in severe cases can cause breathing difficulties and fainting. Also, the airborne pollutants generated when coal, firewood, and other materials are burnedblack carbonhas been suggested to be potentially carcinogenic. Also generated during combustioncarbon dioxidecan cause dizziness, nausea, and disorientation if concentrations are high.

This has been a problem in recent years.PM2.5is the diameter2.5μm(in Japanese history)note 1It represents very fine particles of less than 1.5 mm (0.01 in) in diameter and includes the above substances, sulfates, aluminum, and others. They are generated by natural phenomena such as volcanic eruptions in addition to human production and consumption activities. Because of their fineness, they easily penetrate deep into the lungs, causing asthma and bronchitis,pneumoniaand other respiratory diseases, or cardiovascular diseases such as cardiovascular disease and arrhythmias.induceDo.

Furthermore, these pollutants can also affect neurodevelopment and cognitive abilities, which may reduce intelligence levelsfindingsalso out.

Global Impact

Let us now look at the specific scale of damage caused by air pollution. Published in the Lancet, the world's most prestigious scientific journalpaper(in Japanese history)2022According to (year),2019Year.1Over the course of a year, "pollution," including air and water pollution, has caused about900As many as 10,000 people died. This is about the total number of deaths worldwide in the same year.6-th (e.g. one fifth)1Equivalent to

The effects of air pollution are particularly horrendous, with about6.67 millionIt is estimated that the deaths of more thanBy RegionLooking at the number of deaths in the1No. 1: East Asia and the Pacific24910,000,000,2No. 1: South Asia21710,000,000,3No. 1: Sub-Saharan Africa93It continues with 10,000,000 people. Next.By CountryIn,1No. 1: China18510,000,000,2No. 2 India:16710,000,000,3No. 1: Pakistan2410,000,000,4No. 1: Nigeria2010,000,000,5No. 1: Indonesia19The above is still the case, as are the 10,000,000 people.3Two regions dominate the list, especially China and India, where more than half of the world's air pollution deaths are concentrated. It can also be inferred that low- and middle-income countries, rather than high-income countries, are ranked among the regions.90% or moreare occurring in low- and middle-income countries. Below is a heat map depicting the number of deaths due to air pollution.

Note, however, that countries with large populations naturally have larger numbers of deaths. The following heat map shows the ratio of air pollution deaths to population.1No. 1: Bahamas0.5%,2No. 1: North Korea0.2%,3No. 1: Solomon Islands0.2%,4No. 1: Taiwan0.2%,5No.1: Somalia0.2The percentage is.

The effects of air pollution are not limited to death. It causes severe illnesses that do not lead to death but make life significantly more difficult, causing people to miss school and work. This leads to economic costs as well. The loss of labor productivity due to death and illness, the reduction of the workforce, and the increase in health care costs arecauseand the global economy is expected to grow at an annual rate ofUS$290 millionIt is estimated that the loss of life is as much as $3.5 billion per year. These economic losses may well lead to further hardships and other causes of death, such as malnutrition and sanitation problems. 

2 Air Pollution

Here, air pollution is2Let us mention that they can be divided into two typologies.1The second is outdoor air pollution,2The second is indoor air pollution.

 Outdoor air pollution is a result of natural and anthropogenic factors2It is thought to occur from two sources. Natural causes include lightning strikes and dryforest fireand savanna fires, and volcanic eruptions. The emitted smoke rises high above the ground and rides the wind across the region toextendThis can lead to air pollution far from the site and affect the health of an unspecified number of people.

 Anthropogenic factors include automobile and factory emissions as well as slash-and-burn and resulting forest fires. For example, in Indonesia2019In 2006, a number of large forest fires occurred frequently, and serious smoke damage was reported that spread to other countries. The cause was the slash-and-burn farming method, in which fires are set in grasslands and mountain areas to create agricultural land. Normally, the fires would naturally extinguish, but due to reduced rainfall and dryness, the fires spread to the surrounding areas, leading to forest fires. This has resulted in the loss of approximatelyOne million peoplepeople complained of respiratory problems, and schools and airport operations were also disrupted.

 Let us now look at indoor air pollution. This includes mainly2Two factors can be mentioned.1The second is living on solid fuels. In fact, about one in four households around the world40%The people who live in the "urban areas" do not have access to modern energy sources such as electricity or gas. Instead, they cook their food by burning wood and coal in kamados, which also serve as heaters when the temperature drops. The smoke emitted in this way contains black carbon and carbon dioxide, which can be harmful to the respiratory tract.

Indian women cooking with firewood (Photo:Mike Prince / Flickr [CC BY 2.0])

 2The second factor is indoorsmokingIt is. The smoke produced by smoking is the mainstream smoke that the smoker inhales directly from the cigarette, the smoke that rises from the combustion parts of the(secondary) tobacco smokeand of the exhalation smoke exhaled by the smoker.3The two The key to indoor air pollution is secondhand smoke and exhalation smoke. Secondhand smoke is unfiltered and contains many times higher concentrations of toxins than mainstream smoke, increasing the risk of lung cancer and heart attack when inhaled.possibilityThere is a Exposure to the combined air of secondhand and exhaled smoke is called passive smoking, which causes a worldwide annual1.2 millionIn the United States, more than 1,000 people have died as a result of smoking indoors without proper ventilation. Indoor smoking without proper ventilation allows high concentrations of toxic substances to remain in the room, exposing people to pollutants for extended periods of time.

In 2019, about 4.51 million people will be affected by outdoor air pollution and about2.31 millionwere reported to have died. Although men are more likely to be killed in both cases, women are more likely to be killed in indoor air pollution than in outdoor air pollution. One reason for this is that women globally spend more time engaged in household chores, including cooking, thanlong (time)The following are some examples.

Shadows creeping over children

Adults are not the only victims of air pollution.5Of the deaths of people under the age of 18, aboutten percentis estimated to be caused by air pollution, and the impact on children is also serious.reasonThe reasons for this are: they breathe at a faster pace than adults; they are shorter and closer to the ground, where pollutants tend to accumulate; they inhale more pollutants; and their developing bodies are less capable of breaking down, detoxifying, and excreting the pollutants they have inhaled. Once taken into the body, the pollutants spread throughout the body via the bloodstream, undermining the young body.

 In addition to the health hazards already mentioned, the educational impact on children is significant. Studies are underway around the world on the relationship between air pollution and education, suggesting that air pollution may have a negative impact on academic and cognitive performance. For example, a study conducted in the U.S.researchfound that students attending schools downwind of the highway had poorer test results and more absenteeism and problematic behavior than students attending schools upwind. It has been speculated that this may be because downwind schools are exposed to more pollutants. In addition, when classrooms are not properly ventilated and carbon dioxide concentrations are elevated, test results are also poorer.resultis out.

 Furthermore, air pollution has an impact on new lives to be born. When pregnant women inhale polluted air, it flows through the placenta into the fetus' bloodstream, increasing the risk of premature birth, prematurity, and stillbirth. Even if the baby is born safely, it is more likely to develop asthma at an early age. There isresearchIn , air pollution is the largest annual60010,000 premature births,300It was shown to be the cause of 10,000 premature babies.

Premature baby born in Egypt (Photo:USAID Egypt / Flickr [CC BY-NC 2.0])

Measures and Issues

What measures can be taken to address this devastation? Let us look at outdoor air pollution and indoor air pollution in turn.

There are three main approaches to outdoor air pollution: First, control the sources of pollution. In China, for example, the hosting of the 2008 Beijing Olympics has led to a strongmeasurewere taken. The shutdown and relocation of factories, as well as the restriction of days when traffic could pass by car license plate numbers, led to a rapid decline in air pollution levels in Beijing and surrounding cities. However, this has not been sustainable, as it has made life significantly more inconvenient for residents and pollution levels rose again as soon as the Games ended.

The second approach is to replace the pollution source with a cleaner one.1990In Germany in the 1950s, a law changed the energy source from coal to natural gas.transitionA good example of this is the fact that Natural gas is characterized by almost no emissions of air pollutants such as sulfur oxides and nitrogen oxides. Through this initiative, Germany has reduced sulfur dioxide emissions by about60%In particulate matter, about82%emissions decreased by 1.5 percent. However, compared to other pollutants, carbon dioxide emissions are lower than coal'sMore than halfThe problem of air pollution and global warming caused by carbon dioxide remains.

The third approach is to encourage people to understand the level of pollution and take action. Kampala, the capital of Uganda, is one of the most polluted cities in sub-Saharan Africa, where air pollution kills more people than any other city.1It is one. To improve the situation, a number of air quality monitors were installed in the city. The information obtained from these monitors is available on the Internet atuploadThe system will be installed in the city's public transportation system, and everyone will be able to check the pollution situation in real time. As a result, it is expected that governments will be able to identify the sources of pollutants, while at the same time increasing residents' sense of urgency about air pollution. Considering that pollution-related deaths are particularly high in low- and middle-income countries, this is likely to contribute significantly to the implementation of pollution control measures.

However, the problem is not so simple. Low-income countries are subject to the wrinkles of high-income countries. Low-income countries have lower labor costs, lower prices, and relatively lax environmental regulations. Therefore, it is more cost-effective to conduct industrial production in low-income countries than in high-income countries, and it is also possible to produce products that emit more pollutants. There arereportAccording to the "Mere Old Man," companies in the U.S., Japan, and some European countries have reduced the number of deaths and economic losses caused by air pollution in their countries by relocating some of their industrial production lines to low-income countries. Thus, while the air in high-income countries became cleaner, pollution in low-income countries became even more severe and deaths increased. There is no doubt that changing attitudes in low- and middle-income countries is an important step toward improving air pollution. However, significant progress will not be made unless people recognize and change their minds about the reality that governments and corporations in high-income countries are shifting the responsibility for air pollution onto the shoulders of other countries.

Factory emitting black smoke (Photo:PxHere [CC0 1.0])

Next, let's look at indoor air pollution. The first essential step is to introduce cleaner fuels. Especially in India, where indoor air pollution is serious in rural areas,2016In 2006, the household energy source was shifted from solid fuels toLNG(LPG) for the purpose of transitioning to LPG,PMUYThe project was initiated to for households that had been cooking with firewood or coal,LPGIn August 2021, a new phase, PMUY 2.0, was launched with more targets than the previous PMUY, and as of August 2022, a total ofMore than 100 millionThe company provides LPG connections for

But here's another thing.question (e.g. on a test)are lurking. In fact, there are many households that are not effectively utilizing the access to LPG provided. The cause is that as international oil prices have risen, so have LPG prices. Poor households in rural areas, whose top priority is food procurement and who cannot afford to buy expensive replacement gas, cannot live on LPG alone, but use firewood or coal as in the past. There are efforts to increase the efficiency of cooking stoves, but they have not improved the situation much.Not connected.It is considered to be a

A similar example isMongoliaIt is also happening in the city of Ulaanbaatar. In Ulaanbaatar, the capital city of Mongolia, coal stoves used to keep out the bitter cold cause very serious air pollution during the winter months. In response, the government has issued a coal ban and recommended the use of semi-fired coke, which emits less air pollutants. However, since coking coal is very inexpensive and readily available in Mongolia, many people still use coking coal to keep warm.

The common denominator is that clean energy is expensive and difficult to reach, especially for the poor. They are forced to seek cheaper energy in order to survive, even though they know it will harm the environment.

In addition to these fuel measures, there are also building structure-related measures. In addition to the pursuit of energy efficiency, appropriate ventilation systems must be installed. By creating air circulation, high concentrations of air pollutants can be avoided from remaining indoors. Specifically, installing ventilation fans, installing chimneys or exhaust vents called slots to release smoke, and shaping the roof toplanare mentioned. However, ventilation allows temperature-controlled air that is heated and cooled to escape to the outdoors, increasing heating and cooling costs. Thus this may be a rather difficult approach for the poor who live in severe heat or cold.

As for the damage caused by smoking, in addition to ventilation, reducing the number of smokers in the first place will go a long way toward improving the situation. As noted above, cigarettes have a tremendous impact not only on the smokers themselves, but also on the people and air around them. Smoking cessation will lead to improvements in outdoor air pollution as well as indoor air pollution.

Smoke rising from a cigarette (Photo:Lindsay Fox / Flickr [CC BY 2.0])

How to Fight Air Pollution

The atmosphere has no borders. The policies of one country, or the activities of one company, can cause great damage to people living far away. Air pollution is a global issue shared by all humankind,1Country,1The company's actions and1It is not something that can be solved by one approach, which is why it is so important for the entire world to align itself with one another. Holding international conferences on air pollution, concluding treaties, and cooperation among countries are essential. It is also important for governments to set specific action guidelines and targets and actively work to control the sources of pollution. At the same time, it is important for people to understand the mechanism of air pollution and the magnitude of the damage it causes, and to demand improvements from their own governments and companies, so that the earth and its inhabitants can be healthy.

1 ㎛ is a unit of length.1The ㎛ is1The㎜1,000-th (e.g. one fifth)1The following is a list of the most common problems with the

Writer:Nao Morimoto

Graphic:Takumi Kuriyama

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