Qualité de l’air à Suzhou

What is the air quality index of Suzhou?

Suzhou is a major city situated in the south-eastern province of Jiangsu which is in the eastern part of China, just 100 kilometres north-west of Shanghai. It is a prefecture-level city with an approximate population of almost 4.5 million in the city and over 10.5 million in the entire administration region.

In early 2021, the air quality in Suzhou was classified as “Unhealthy” with a US AQI reading of 163. This is according to the recommended figures from the World Health Organisation (WHO). The recorded levels of the pollutants were as follows: PM2.5 - 79.5 µg/m³, PM10 - 160.5 µg/m³, ozone (O₃) - 5 µg/m³, nitrogen dioxide (NO₂) - 79.5 µg/m³, sulphur dioxide (SO₂) - 15.5 µg/m³ and carbon monoxide (CO) - 1100 µg/m³. With levels such as these, it is recommenced to wear a quality mask when venturing outside. Doors and windows should be kept closed to prevent the ingress of dirty air into the home. Any form of outdoor exercise should be avoided until the quality improves.

What is the main source of Suzhou’s polluted air?

As a large industrial city, Suzhou ranks among the top cities of the same type in the country, whether it is the total amount of coal burning, industry, the number of motor vehicles, and the total amount of construction in progress, with a large base of air pollution sources and a wide variety of types. With regional and compound characteristics, the situation of air pollution prevention and control is very severe and not optimistic.

Combined with the specific reality of motor vehicle exhaust pollution, as early as a few years ago, exhaust pollution became the main source of air quality pollution in Suzhou City.

While the city is changing rapidly, construction, transportation and dust pollution brought about by other countries is becoming more and more serious, becoming one of the important factors affecting the environmental air quality of the city.

Does air pollution in Suzhou differ throughout the year?

In the autumn and winter of 2018-2019, the weather conditions were not as good as those in the previous two years. From May to November, the quality of air In Suzhou falls into the “Moderate” category with figures of around 12.1 to 35.4 µg/m³. During the colder, winter months, the quality decreases with recorded figures of between 35.5 and 150.4 µg/m³.

The mean figure for 2019 was 37.7 µg/m³ which is classed as “Unhealthy for sensitive groups”. However, this is a slight improvement on the previous years of 2017 and 2018 which returned figures of 41.5 and 40.3 µg/m³, respectively.

What can be done to improve the air quality in Suzhou?

In July 2020, Suzhou's air quality broke the record for the shortest time to reach the standard. As of 30^th July, the PM2.5 concentration of fine particulate matter in Suzhou City had reached the national air quality standard limit of 35 µg/m³ for the first time, which is a good start for the annual PM2.5 concentration. This is also the best result of PM2.5 set by Suzhou since records began. Data shows that since this year, the PM2.5 concentration in downtown Suzhou is 34.9 µg/m³, down 17.4 per cent year-on-year. The 8-hour moving average percentile concentration of ozone was 165 µg/m³, a year-on-year decrease of 5.9 per cent and the proportion of days with good air quality was 83.6 per cent, a year-on-year increase of 8.6 per cent.

All vehicles registered in Suzhou, whether new or second-hand must pass the emissions standards before being granted a licence. This is one way of discouraging the purchase of old, polluting vehicles from other provinces. Conversely, it has raised the "threshold" for new vehicles to be licensed so they must meet the National V emission standards. However, whether it is from the number of motor vehicles or the growth rate, the pressure on the prevention and control of exhaust pollution is considerable. Currently, Suzhou has more than 2.9 million motor vehicles, and more than 340,000 new vehicles were added in 2015 alone. If the “restriction on migration” of second-hand cars is abolished and the “red line” of car registration is broken, then the consequences will be truly unimaginable.

Road cleaning operations shall meet the following requirements for the prevention and control of dust pollution. Except for rainy days and where the minimum temperature is below 2 degrees Celsius, the motor vehicle lanes on main urban roads shall be sprayed at least once a day with water. The main roads and elevated roads in the city shall also be sprayed on a daily basis, and the minor roads are to be wetted when possible.

In order to prevent dust pollution caused by vehicles that transport materials that are prone to fugitive dust pollution, regulations stipulate that units and individuals transporting materials that are prone to fugitive dust pollution should be transported in enclosed or covered vehicles.

There is also stipulation that the construction units that disposes of construction waste and the transportation units that transport engineering slag shall report to the city or county-level city Urban Management. The administrative department shall apply for approval for the disposal of construction waste and engineering residue and obtain the construction or engineering residue disposal certificate before disposal is permitted.

What are the health risks associated with Suzhou’s poor quality air?

Big data analysis by the Suzhou Centre for Disease Control and Prevention shows that among the top ten causes of death in Suzhou citizens, chronic diseases account for 96 per cent, and malignant tumours account for nearly 30 per cent as the primary cause of death. In response to these problems, Suzhou City has carried out medical and health reforms based on the needs of the people, coordinated solutions to public health problems, carried out system design, planned resource allocation, and used practical system guarantees to form an effective supply of limited resources.

Many new facilities have recently been built to provide early health care for those who become ill due to the poor quality air. Screening facilities have been made available and 620,000 senior were screened last year.

In 2019, the average life expectancy of Suzhou city reached 83.54 years, ranking second amongst cities throughout the country. The neonatal mortality rate dropped by 18 per cent compared with 2016, and the level of health literacy increased by 5.86 percentage points compared with 2016.