Qualité de l’air à Nagoya

Does Nagoya have polluted air?

Nagoya is a city in the Chubu region of Japan, finding itself not too far from other big cities such Kyoto and Shizuoka. It is among one of several major port cities in Japan, and has a history of being heavily involved in the industry of producing metals, particularly steel, as well as chemical manufacturing, oil and petrochemical processing, as well as the production of vehicles and airplanes. This history of being a major commercial hub continues on today, as well as being home to some 2.3 million inhabitants.

Due to a strong industrial infrastructure, as well as the movement of people in their day to day lives, cities such as Nagoya are subject to elevated levels of pollution, with some months coming in more prominently due to both meteorological and anthropogenic (human caused) factors.

Looking at its air quality readings over 2019, Nagoya came in with a PM2.5 reading of 11.7 μg/m³, placing it into the ‘good’ ratings bracket of air quality. This requires a PM2.5 reading of 10 to 12 μg/m³ to be classified as such, a very fine margin of entry and only 1.7 units away from being moved into the most optimal category of the World Health Organizations target goal for 10 μg/m³ or less, for the best quality of air possible.

Nagoya's reading of 11.7 μg/m³ put in 1914^th place out of all cities ranked worldwide, as well as 215^th place out of all cities ranked in Japan. Whilst it has a respectable quality of air, there are a few issues that skew its yearly average and cause certain months to come in with elevated levels of pollution.

What are the main causes of pollution in Nagoya?

With a large amount of people inhabiting Nagoya, there would be a subsequent elevated amount of pollution caused by the mass movement and transiting of the city’s inhabitants. Essentially this means that in modern times, a large amount of pollution would be caused by the use of vehicles, with a huge amount of cars and motorbikes inhabiting the roads of Nagoya.

Although it (along with many cities in Japan) has a substantial amount of public transport infrastructure, there still remains a large amount of dependency on vehicular usage, and can be witnessed most prominently during rush hour times, where massive amounts of vehicles move across the busiest sections of the city, causing sudden spikes in particulate matter and other pollutants.

Other causes of pollution include ones such as the use of diesel fuels in heavy duty vehicles such as trucks and lorries, as well as heavy machinery in factories and industrial areas giving off their own pollutants. These factories themselves often rely on fossil fuel sources for energy, utilizing materials such as coal to provide energy. The combustion of both diesel and coal, as well as the chemicals released from industrial processes can all add to the number of contaminants in the atmosphere, driving up year round ambient pollution levels.

When is the air quality at its best in Nagoya?

Looking at the data taken over 2019, as is similar to many other cities in Japan, there is not a distinct period of time where the levels of PM2.5 are overtly elevated and other parts of the year where they are distinctly lower. Rather the readings appear to be quite sporadic in their nature. One thing that is consistent is that the air quality across many cities, including that of Nagoya, seems to improve by some small margins at the end of the year.

Looking at the last few months of the year in 2019, it can be observed that Nagoya's PM2.5 levels were at their lowest in September through to December, with October and December having the best readings of the entire year, being the only two months of the year that came within the WHO's target goal of 10 μg/m³ or less.

October had a reading of 9.7 μg/m³, and December came in with a reading of 10 μg/m³. This displays that October was the cleanest month out of the entire year, followed closely by December and then with November and September following suit with readings of 10.1 μg/m³ and 10.2 μg/m³ respectively.

When is pollution at its worst in Nagoya?

In contrast to the previous question, the opposite times of the year are when Nagoya's air will be at their most permeated with smoke, haze, smog or any other forms of airborne contaminants. After the cleaner months at the end of the year, January came around with similar clean readings, with a reading of 10.5 μg/m³, putting it in the lower end of the ‘good’ ratings bracket and still fairly respectable.

However, from there on out the air quality levels started to worsen fairly rapidly, making a jump up to 15.5 μg/m³, a reading that placed that month into the ‘moderate’ pollution bracket (12.1 to 35.4 μg/m³ required).

From February until August is when the pollution levels in Nagoya were at their worst, fluctuating between good and moderate readings. The months of February, March, May, June and August all came in with moderate rankings, indicating a higher level of pollution. The month that had the highest out of all of them was the previously mentioned February, with its PM2.5 reading of 15.5 μg/m³.

What are some health problems associated with pollution in Nagoya?

Whilst there would not be any overt health risks of living in a city such as Nagoya, it should be noted that any reading above the WHO's target rating of 10 μg/m³ or less, or indeed any reading of pollution, carries with it inherent risks for adverse effects. In the months such as February where the PM2.5 levels rise to moderate and above, the health risks would rise accordingly.

Some would include rapid aging or damage to the lungs, as well as the triggering of preexisting respiratory conditions such as aggravated asthma or bronchitis. Nitrogen dioxide can set off asthma attacks as well as damage the lining of the lungs, and particulate matters released from factories and exhaust fumes can cause irritation to the throat, eyes, mouth and eyes. Expectant mothers are the most at risk, which long term exposure to pollution causing instances of miscarriage, or babies being born prematurely or with a low birth weight. These are but a few of the negative side effects associated with higher levels of pollution in the air in Nagoya.