Air quality in Saint-Denis

What is the current level of air pollution in Saint-Denis?

Saint-Denis is a commune in the northern suburbs of Paris, France. It is less than 10 kilometres from the city centre. A census conducted in 2018 estimated the population to be approximately 112,100 residents.

Towards the end of 2021, Saint-Denis was experiencing a period of “Moderate” air quality with a US AQI reading of 55. This United States Air Quality Index number is calculated using the levels of six of the most prolific air pollutants, such as nitrogen dioxide, sulphur dioxide, ozone, carbon monoxide and both sizes of particulate matter, which are PM2.5 and PM10. It can then be used as the metric when comparing air quality in other cities around the world. If data is unavailable for all 6 pollutants, a figure can still be calculated by using what figures there are. In Saint-Denis, the only pollutant measured was PM2.5 which was 14.1 µg/m³. This level of PM2.5 is just lower than one and a half times the recommended safe level of 10 µg/m³ as suggested by the World Health Organisation (WHO) as being an acceptable level. Although no amount of air pollution is considered to be safe.

When air quality is classed as being “Moderate” the given advice would be to remain indoors as much as possible, closing doors and windows to prevent more dirty air from entering the rooms. Those who are more sensitive to poor quality air should avoid venturing outside until it improves. If this is unavoidable, then a good quality face mask should be worn at all times. There is a downloadable app from AirVisual.com which is suitable for all operating systems which gives the latest information regarding air quality in real-time.

Does the level of air pollution vary throughout the year in Saint-Denis?

Air quality is very volatile as it can be affected by many variables and can change very quickly. Looking back at the 2020 figures published by IQAir.com, it can easily be seen that for eleven months of the year Saint-Denis experienced a period of “Moderate” air quality with figures between 12.1 and 35.4 µg/m³. The cleanest month was May with a reading of 14.4 µg/m³, the dirtiest was November with a 21.1 µg/m³ reading. The month of February returned a figure of 11.1 µg/m³ which is classified as being “Good”.

Historically, records for air quality were first kept in 2017 when a figure of 19.5 µg/m³ was noted. 2018 saw a slight improvement when the figure there was 17.6 µg/m³. 2019 continued this trend with a lower figure of 16.3 µg/m³ which continued into 2020 with a reading of 15.9 µg/m³.

This was to be expected because it may have been affected by the COVID-19 pandemic as many vehicles were no longer in daily use because the offices were closed, in an attempt to halt the spread of the virus. Many factories and non-essential production units were also required to close which removed their emissions from the atmosphere, albeit on a temporary basis. Worldwide, cities reported a much better quality of air due to the general lack of traffic pollution in city centres due to the pandemic.

Is there a main source of air pollution in Saint-Denis?

In Île-de-France, there are many sources of air pollution. Transport, district heating, economic activities, construction site, agricultural waste, etc. The Region provides support for experiments to test innovative solutions.

Road traffic is responsible for more than 50 per cent of nitrogen oxide emissions and 20 per cent of direct emissions of fine particles. This has an influence on pollution near road axes: for nitrogen dioxide, the levels there are up to twice the regulatory values.

Road traffic is also responsible for nearly 10% of non-methane volatile organic compound (NMVOC) emissions and 15 per cent of ammonia emissions in the region. Through heating, the residential and tertiary sector is the main emitter of fine particles and non-methane volatile organic compounds (NMVOC) in the region. It represents a third of the emissions of fine particles less than 10 micrometres (PM10), more than 50 per cent of the emissions of fine particles less than 2.5 micrometres (PM2.5), and 34 per cent of the emissions of non-methane volatile organic compounds (COVNM). Note the very high contribution of individual wood-burning equipment which contributes almost 30 per cent to emissions of fine PM10 particles and 45 per cent to emissions of fine PM2.5 particles in Île-de-France.

Can anything be done to improve air quality in Saint-Denis?

Major sources of urban outdoor air pollution could be reduced through policies and investments in cleaner transport, more energy efficient housing, power plants and industries, and better management of municipal waste.

In addition to outdoor air pollution, household smoke poses a serious health risk to some 2.6 billion people who cook and heat their homes using biomass, petroleum and coal.

Electricity generation: increased use of low-emission fuels and renewable energy sources that do not require combustion (e.g., solar, wind or hydroelectric); cogeneration of heat and electricity; decentralized energy production (for example using mini-grids or rooftop solar panels.

Transport: transition to clean electricity production methods; priority to rapid public transport, walking and cycle paths in cities, as well as intercity rail transport of goods and passengers; transition to less polluting industrial diesel vehicles and to low-emission vehicles and fuels, including reduced sulphur fuels.

What are the health impacts of breathing dirty air in Saint-Denis?

In France, now more than 4 million people are affected by asthma and 50,000 people suffer from severe respiratory failure.

Pregnant women are all the more vulnerable and sensitive to the air pollution they breathe for themselves but also for their babies. Poor air quality can cause complications for mother and child. Indeed, fine particles can enter the maternal respiratory system and cause a slowdown in the development of the foetus, especially during the formation of the lungs and respiratory tract. The development of certain allergies as well as asthma can also be linked to poor air quality during pregnancy.

At birth, our lungs are not yet fully developed: they will continue to develop approximately until we are 8 years old. In addition, a child breathes about twice as fast as an adult. If the air is polluted, it will therefore breathe twice as many pollutants.