Air quality in Japan

What is the air quality forecast for Japan?

Japan is an island nation spanning an archipelago of around 7000 islands. There arefive main islands which are Hokkaido, Honshu, Shikoku, Kyushu, and Okinawa. Itis situated in the northwest pacific area and is classed as part of East Asia.Tokyo is the capital city where the metropolitan area has a population ofaround 37.5 million residents.

At the beginning of 2021, Japan was enjoying relatively good quality air with a USAQI reading of 47 which classified it in the “Good” category according torecommended figures by the World Health Organisation (WHO). The average PM2.5figure for 2019 was 11.7 µg/m³ which, again, placed it in the “Good” category.For three months of that year, it attained the WHO target figure of 10 µg/m³ orless. Four months classed it as “Good” with readings between 10 and 12 µg/m³.The remaining 5 months called it as “Moderate” with figures between 12.1 and35.4 µg/m³. Looking back over the previous years, the air quality can be seento be improving. In 2017 it was 13 µg/m³ and in 2018 it was 13.1 µg/m³ whilst the levels in 2019 were 11.7 µg/m³.

What is the history of air pollution in Japan?

The history of air pollution in Japan goes back to the Meiji government's policyera of encouraging the rapid development of industry, where pollution was notconsidered, but the problem intensified from the period of high economic growthin the 1950s. A large amount of oil and coal were burned in order to providethe energy which was necessary for post-war reconstruction and to boost thenational income. Pollution centred on sulphur oxides (SO_x) which was becoming serious. As a result ofthis, in industrial cities all over the country, many people suffered fromrespiratory disorders which became known as Yokkaichi asthma.

As people became more aware of the poor quality air, the anti-pollution movementintensified nationwide and measures related to pollution control were promoted,since then, various regulations such as the introduction of the Air PollutionControl Law and promotion of resource saving and energy saving have beenencouraged, and the air quality has improved significantly.

In recent years, air pollution derived from automobiles has increased, andcross-border air pollution from the rapidly growing Asian region has alsobecome noticeable. In response to these problems, the government has introducedvarious regulations such as tightening automobile emission regulations, but thecurrent situation is that the environmental standards set by the government forthe protection of health and the environment are still insufficient.

What are the main causes of air pollution in Japan?

There are three main sources of air pollution in Japan which are as a result ofindustrial production activities, vehicle emissions and cross-border air pollution.

Although there has been a marked improvement compared to the period of high economicgrowth, air pollutants such as sulphur oxides (SO_X) and nitrogenoxides (NO_x) are still emitted from factories and thermal powerplants. Since these air pollutants are regulated by the Air Pollution ControlLaw, each company is obliged to have a dust collector installed that separatesand removes particulate matter in gas, and smoke exhausts that remove sulphuroxides and elementary oxides in the exhaust gas. Further reductions are soughtafter in order to reduce it by using technologies such as desulphurisation and flue gas denitrification.

According to the final energy consumption by sector of the Agency for Natural Resourcesand Energy, it decreased only slightly between 2010 and 2017. Technology toreduce air pollutants is advancing annually, but in order to reduce pollutantsfurther, it is required to reduce energy consumption during the production phase.

Air pollution in Japan is also caused by the exhaust gases given off from vehicles,the increase in the number of cars owned, and the concentration of traffic in big cities.

What can be done to improve air quality in Japan?

The government is introducing tighter regulations on automobile exhaust gases, butthe current situation is that the achievement of environmental standards is unsatisfactory.

In 2017, according to the Ministry of the Environment's air pollution condition, theachievement rate of fine particulate matter or PM2.5 environmental standardshad decreased by 1.9 per cent from the previous year at the AutomobileEmissions Measurement Bureau, and ground-level ozone (O₃) was anextremely low level with an increased rate of 0 per cent.

However, the achievement rate of other air pollutants such as suspended particulatematter (PM10) and nitrogen dioxide (NO₂) is 100 per cent or veryclose, and PM2.5, which normally has a poor achievement rate, is alsoemission-regulated. It is expected that it will be improved by strengthening the system and developing new technologies.

Air pollution caused by fuel consumption in thermal power plants, factories,automobiles, etc. in the Asian region where industrial development is progressing, is also affecting Japan.

Combustion of fossil fuels releases air pollutants such as nitrogen oxides (NOx) andvolatile organic compounds (VOCs) into the environment which produces harmful ozone(O₃). In Japan, these pollutants are decreasing annually due tosource regulations, but it is thought that cross-border air pollution is themain reason why ground-level ozone does not decrease in significant numbers.

According to the National Institute for Environmental Studies, the rate of increase in nitricoxides (NOx) and volatile organic compounds (VOCs) emissions in Asia from 1980to 2003 was 2.8 times for NOx in Asia, 2.6 times in East Asia, and 2.1 times for VOC in Asia. In East Asia, it is 2.4 times.

In particular, it can be seen that China has increased significantly, with NOx 3.8 times and VOC 2.5 times.

The Ministry of the Environment will comprehensively promote measures such asemission control measures from factories and business establishments,automobile exhaust emission controls, and the encouragement of the use oflow-emission vehicles in order to continue to achieve and maintain environmental standards.

This will also include the strengthening and creation of measures to control theemission of air pollutants, which are the source of fine particulate matter andphotochemical oxidants, analysing the current situation and organisinginformation, and reassess the situation if progress is slow.

Which city in Japan has the highest levels of air pollution?

Imari, Saga has the most polluted air according to the Swiss air monitoring company,IQAir.com with a US AQI figure of 63. This is possibly due to the widespreadmanufacture of porcelain in and around this area. Imari porcelain is exported worldwide and is of very high quality.

The cleanest city in Japan is Obihiro, Hokkaido with a recorded level of 24 whichclassifies it as being “Good”. In 2008, Obihiro was designated a "modelenvironmental city" in Japan. There is a large agricultural communitysurrounding Obihiro and not too many factories which are the main cause of pollution.

What does the future hold with regards to air quality in Japan?

Currently, the two main sources of air pollution in Japan are fixed sources such asfactories and business establishments and mobile sources such as automobiles and aircraft.

In particular, air pollution caused by nitrogen oxides (NOx) emitted fromautomobiles, which are the source of mobility, is serious, and nationalmeasures such as automobile emission regulations and promotion of the spread of low-emission vehicles are being promoted.

In order to control sulphur oxides (SO_x) and nitrogen oxides (NO_x)emitted from thermal power plants, electric power companies use petroleum fuelswith low sulphur content and take measures such as installing flue gas desulphurisation equipment.

For those who use automobiles and motorcycles for commuting, simply switching themeans of transportation to public transportation, walking, or biking would helpsignificantly in reducing emissions and would make a big difference to environmental pollution.

Exhaust gas is not only emitted when the car is running but also when the vehicle isidling such as waiting in a queue at traffic lights.

What are the effects on health by breathing Japan’s poor quality air?

Fine particulate matter (PM2.5) or micro particulate matter is suspended in the air duringstandby and is characterised by a fairly small diameter of 2.5 microns. It isknown to be generated mainly from the combustion of fossil fuels which causesoot and dust from sources such as factories, automobiles, ships, and aircraft.

The big problem is that fine particulate matter is microscopic and if it is inhaledinto the lungs where it penetrates deeply and lodges at the base of thebronchial tubes. Therefore, it is thought to increase the risk of respiratorydiseases such as asthma and bronchitis.

Spring is the season when the concentration of PM2.5 rises and is at its highest. Adaily average of 70 μg / m₃ may have detrimental health effects.

Overall, the annual average concentration of PM2.5 in Japan is declining due toregulations on soot and smoke generating facilities such as factories andbusiness establishments, together with automobile emission regulations.However, PM2.5 concentration fluctuates depending on the season, and theconcentration tends to increase from March to May every year. There are alsodifferences depending on the region and the weather conditions at the time.

Short term symptoms resulting from exposure to air pollution include itchy eyes, noseand throat, wheezing, coughing, chest pain, headaches, nausea, and upperrespiratory infections such as bronchitis and pneumonia. In some cases it canalso cause a rash to form on the skin but, of course, this depends on thecontents of the air and the susceptibility of the individual. It alsoexacerbates asthma and emphysema. Long term effects may include lung cancer,cardiovascular disease, chronic respiratory illness, and developing allergies.Air pollution is also associated with heart attacks and strokes.

The effects are very dependent on the state of health of the individual. Pregnantwomen, children under the age of 14 years and the elderly will be moresusceptible than young healthy people with no pre-existing medical problems. The level of concentrations and the length ofexposure also play an important role.

How is technology helping people to monitor the air quality in Japan?

The achievement rate of environmental standards for fine particulate matter hasimproved from 89.9 per cent for general stations and 86.2 per cent forself-exhaust stations to 93.5 per cent for general stations and 93.1 per centfor self-exhaust stations. However, there were some areas in the Kanto region, theurban areas in the Kansai region and coastal areas that did not meet the environmental standards.

General stations are measuring stations which have been installed for the purpose ofmeasuring air pollutants in general living spaces such as residential areas. Self-exhauststations are measuring stations which monitor the pollution status from automobile exhausts.

In the transportation, railway, and aviation industries, new regulations withregards to air pollutant exclusion standards are being introduced together withthe development and introduction of low-emission vehicles and energy-savingaircraft. In logistics, curbing carbon dioxide (CO₂) and nitrogenoxide (NO_x) emissions through a “modal shift” that shifts freighttransportation to railroads and shipping are being gradually phased in, which have less impact on the environment.

Are electric cars the way forward in Japan?

All efforts are being made based on the "Automobile NOx / PM Law", aspecial law aimed at reducing pollutants emitted from vehicles, but the spreadof electric vehicles is particularly attracting attention as a countermeasureto nitric oxides (NOx). Since electric vehicles run on motors using electricitystored in batteries, they do not emit any exhaust gas and emit fewer pollutantsubstances and carbon dioxide (CO₂) than ordinary gasoline-powered vehicles.

Furthermore, if charging with renewable energy such as solar cells becomes common, it will becomeunnecessary to consider emissions from power plants, and nitric oxides (NOx)and carbon dioxide (CO₂) emissions from automobiles can be reducedto zero. In this way, electric vehicles are highly expected, but there areproblems to overcome, such as high vehicle prices and maintenance costs, arelatively short-range, and lack of charging stations, and furthertechnological development for full-scale popularisation.

Recently, the number of passenger cars used for private use has increased from gasoline cars to eco-energy cars that usehydrogen and electricity, and "hybrid cars" that use both eco-energy and gasoline.