Qualité de l’air à Pékin

What is the air quality index of Beijing?

Beijing is the capital city of the People’s Republic of China and was formerly known as Peking. It is the world’s most populous city with an estimated population of over 21 million residents. The city is located in the northern part of China and covers an area of 16,500 square kilometres.

At the end of 2020, the air quality index for Beijing recorded a figure of 52 US AQI. This classes it as “Moderate” according to the recommendations suggested by the World Health Organisation (WHO). Other pollutants were measured with the following results: - PM2.5 = 12.5 µg/m³, PM10 = 33 µg/m³, ozone (O₃) = 43 µg/m³, nitrogen dioxide (NO₂) = 24 µg/m³, sulphur dioxide (SO₂) = 4 µg/m³ and carbon monoxide (CO) = 400 µg/m³. The figures are stated as micrograms per cubic metre.

In 2019 China was classed as the 11^th dirtiest country in the world. The city of Beijing was ranked at 201.

Throughout 2019, Beijing had just two months when the air quality was classified as “Moderate” with readings between 12.1 and 35.4 µg/m³. The remaining ten months showed readings of 35.5 to 55.4 µg/m³ which categorised it as “Unhealthy for Sensitive Groups”, according to The WHO. This was an improvement on previous years, though when recorded figures were 50.9 and 58.8 µg/m³ for 2018 and 2017 respectively.

What are the main sources of air pollution in Beijing?

Beijing air pollution is mainly caused by vehicle emissions and the burning of coal to produce electricity. Other factors that influence air quality in Beijing include the manufacturing industry and population growth.

Of the twenty cities throughout the world with the worst air quality, 16 of them are located in China. Because of this, its Environmental Sustainability Index is ranked towards the bottom amongst countries worldwide.

An increase in personal wealth can also have an influence here. With surplus money at the end of each month, an individual is more able to buy a car. The number of motor vehicles in Beijing in 2017 was estimated at 5.5 million.

Is the air quality in Beijing getting better or worse?

In the last 15 years, China has been steadily improving its air quality. It reduced levels of PM2.5 by 47% between 2005 and 2015. Beijing recorded its lowest ever monthly reading for air pollution in August 2019, with a low of 23 µg/m³. The main reasons for the reduction of air pollution in China are the shift from coal to natural gas in the power stations, the large number of electric vehicles used by the people and the effort from the Chinese government to halt deforestation in the country.

What are the health effects of Beijing’s polluted air?

When the air quality in Beijing is at its worst, people are urged by the government to avoid outdoor activities. Most common health issues are a sore throat and cough. Over the past decade, lung cancer rates have risen by over 60%. Other consequences of air pollution in Beijing include yellow skies, higher mortality rates, and cancelled flights due to low visibility levels.

Air pollution is very serious in many parts of the world. Nine out of ten people in the world breathe polluted air, and the death toll caused by air pollution reaches 7 million every year. Up to one third of deaths caused by stroke, lung cancer and heart disease are due to air pollution. Air pollution is everywhere. No matter where you live, you cannot escape. The fine pollutants in the air break through our body's defences, penetrate into our respiratory and circulatory systems and damage our lungs, heart and brain.

The main pollutants in the air include Particulate matter which is a mixture of solids and liquid droplets mainly from fuel combustion and road traffic; nitrogen dioxide (NO 2) from road traffic and organic material combustion; sulphur dioxide (SO₂) burning fossil fuels and ground-level ozone (O₃) produced by the reaction of sunlight with pollutants in vehicle exhaust.

The pollutant that affects people the most is particulate matter, usually abbreviated as PM and used as a measure of air pollution. Although particles with a diameter of 10 microns or less (≤PM10) can penetrate and embed deep in the lungs, the ones that are more harmful to health are those with a diameter of 2.5 microns or less (≤PM2.5). These particles are very small, only one 60th the diameter of a human hair.

Ozone (O₃) is a major factor in causing asthma (or making it worse). Nitrogen dioxide (NO₂) and sulphur dioxide (SO₂) can also cause asthma, bronchial symptoms, lung inflammation and decreased lung function.

More than 90% of children in the world breathe heavily polluted air every day, putting their health and development at serious risk. In 2016, 600,000 children died from acute lower respiratory infections caused by polluted air. One reason why children are particularly vulnerable to air pollution is that they breathe faster than adults and therefore absorb more pollutants. In addition, the living space of children whose brains and bodies are still developing is closer to the ground, where some pollutants have the highest concentrations. Air pollution can also affect children's neurodevelopment and cognitive abilities and may cause asthma and childhood cancer. Children exposed to high levels of air pollution may have a higher risk of developing chronic diseases such as cardiovascular disease in later life.

What can be done to improve Beijing’s air quality?

The local authorities in Beijing realised how successful their policy to reduce traffic was for the 2008 Olympics. The most common way of reducing traffic is to prohibit certain vehicles from entering certain areas on certain days of the week. Automobiles within the 5th Ring Road shall not be allowed on public roads for one day each week according to the end number on their license plate: from Monday to Friday, automobiles with end numbers 1 or 6, 2 or 7, 3 or 8, 4 or 9, 5 or 0 respectively would cease going on public road space. There is a time-frame to accompany these rules which are the hours between 07:00 to 20:00 as being the prohibited times. These exclusions would last for about 3 months before changing to allow different vehicles into the city on different days.

As expected, these rules and regulations do not apply to electric vehicles (EVs). These vehicles emit no toxic waste and are therefore encouraged to be used. The government offers incentives to people who buy and use electric cars. Some owners regard them as being ideal for use within the city limits but remain sceptical as to how suitable they are for longer journeys out of town. The fear is a lack of recharging hubs or the lack of knowledge as to where they are located. No doubt there is an app that can be downloaded to your phone, which would help, but the confidence to use them for longer journeys is just not there.

China will ban all new coal-fired power stations and start to replace existing ones with natural gas as a power source. In some parts of China, steel production has been reduced.

According to data from the Ministry of Environmental Protection, from October to November 2018, Beijing's PM2.5 concentration dropped by more than 40% year-on-year, and the monthly data in November fell 54% year-on-year. In November last year, the proportion of days with good air in Beijing was 80%, and heavy pollution occurred for 1 day. In November 2016, the proportion of days with good air in Beijing was 43.3%, with heavy pollution for 6 days and severe pollution for 1 day.

In recent years, the smog in Beijing has been criticized. In autumn and winter, social media will be "screened" by air pollution warnings and grey haze photos, and the streets will be full of Beijing residents wearing masks walking hurriedly.

PM2.5 can be divided into primary source and secondary source, which are both man-made and non-man-made, which is very complicated. There are thousands of sources of PM2.5, some of which are unclear. Research data includes monitoring data, meteorological data, pollutant emissions, source characteristics, and seasonal changes. The current data is very limited and more research is needed.

Actions that can save lives and help save the planet include raising vehicle standards, prioritising clean public transportation and ways to promote physical activity, and using more efficient stoves and fuel alternatives for cooking, lighting, and heating.

Can the smog in Beijing be controlled?

The most important way to control smog is to reduce emissions. The large-scale use of various fossil energy sources is the main cause of hazy weather. You need to burn coal to generate electricity. In fact, less than 30% of the coal burned is converted into electricity, and the rest is discharged. Automobiles, ships and other machinery need petroleum. Similarly, engines only convert less than 30% of petroleum into power, and the rest is also discharged. In other words, our energy use is "expensive", less use and more emissions. It is unrealistic to reduce energy use, and clean energy is far from being able to meet demand and is expensive. If 70% of the existing energy can be used and 30% of the emissions can be used, the environmental and energy problems will be solved at the same time, and the human society will have sustainable development.

Also, plant more trees for afforestation. Afforestation is of great significance for regulating climate, conserving water sources, and reducing air pollution. Because trees can absorb carbon dioxide and release oxygen. They can also withstand wind and sandstorms, and at the same time can also beautify the environment. Artificial afforestation can be divided into five types of timber forests, protection forests, economic forests, firewood forests and special purpose forests according to different management purposes and characteristics. For example, bamboo, willow, oleander, locust trees, camphor trees, yew and so on. This requires the participation of many people, because it not only beautifies the homeland, reduces the harm of soil erosion and sandstorm damage to farmland, but also effectively improves the carbon storage capacity of the forest ecosystem.

Beijing has established a coordinating organisation including 13 municipal departments and 16 district and county governments. When heavy pollution occurs, each district and county must take corresponding emergency measures according to its own situation.

The "Regulations on the Prevention and Control of Air Pollution in Beijing" began to solicit public opinion from the whole society. The municipal government can take measures to restrict traffic in certain areas according to the quality of the air environment; key pollution sources should follow the regulations in their own units. Websites or other public places disclose information such as the pollutant discharge situation that it monitors by itself. This series of powerful measures is expected to ensure its implementation through regulations. Beijing will continue to prevent and control air pollution through nine major measures including the development of new energy sources and the reduction of automobile exhaust emissions.

It could be mandatory to install desulphurization, denitrification and dust removal facilities in all coal-fired power plants, coal-fired boilers, and coal chemical plants. On the basis that most of the existing independent thermal power plants have installed desulphurization facilities, all independent thermal power plants, self-built thermal power plants, coal-fired boilers and coal chemical plants will be further required to install desulphurization facilities as soon as possible. At the same time, all large coal-fired power plants, coal-fired boilers and coal chemical plants will be required to install denitrification and dust removal facilities.

The cause of smog is mainly due to the increase in traffic in the city centres and the greatly increased emissions of car exhausts and also because of the increase in carbon dioxide released by heating in winter. Another reason is that dust rises off the ground and into the air, which also provides conditions for the generation of haze. If people remain in the hazy environment for extended periods of time, it may cause problems in the respiratory system. The risk of trachealis and emphysema may increase greatly, and it may also increase blood pressure and heart function problems.

What caused the strongest sandstorm in the past ten years which turned the skies over Beijing orange?

In the early months of 2021, China had been hit by the strongest sandstorm in the past 10 years.

There was a strong cyclone blowing across from Inner Mongolia and towards north-western China, from northern Xinjiang to central and western Gansu. Strong winds were blowing at between 8 to 10 times stronger than is normal at this time of year.

Beijing Meteorological Observatory issued a blue gale warning and a blue sand and dust warning to remind citizens to protect themselves against sand and dust.

According to data released, the highest PM10 concentration was 6496 µg/m³ in the Beijing suburbs and several other readings were reportedly off the scale. On the AQI website the US AQI number was reported as being 1960 which puts it firmly in the "Hazardous" category.

Many local people put pictures on the social media site “WeChat” which almost turned the situation into a scene from a sci-fi movie with yellow and orange filters which gave their pictures an eerie retro look.

Fortunately, after the peak during mid-morning, the level of sand and dust in Beijing had abated, and the visibility had improved significantly since then.