Every day, we breathe between 10,000 and 20,000 litres of air depending on our body size and physical activity to provide our bodies with the oxygen they need. This air contains natural pollutants such as dust or pollen and primary and secondary particles. Primary particles come mainly from industrial and domestic activities, transport and agriculture. Secondary particles are formed in the atmosphere by chemical reactions involving compounds such as sulphur dioxide (SO2), nitrogen oxides (NOx) and volatile organic compounds (VOCs).
These particles are classified according to their size. The smaller they are, the more dangerous they are for human health. We are talking about PM10 and PM2.5. Let's take a closer look at what What PM2.5 particles are ?
Definition of PM2.5 particles
These are all airborn particles whose diameter measures less than 2.5 micrometers (µm). They contain residues of smoke (car exhaust gases, industrial fumes and wood combustion), soot, various dusts (construction, soil work, wind), aerosols, droplets or biological materials such as mold, bacteria or pollen.
The term PM comes from Particule Matter. As they are solid or liquid particles, they have a physical dimension unlike gases.
What are the differences with PM10 fine particles?
PM10 as their name indicates are particles with a diameter of less than 10 µm. They are generally blocked naturally at nose level. PM10 and PM2.5 are the particle sizes measured by the various international health services in order to be able to compare common standardized values. It is also a way of not being too often in pollution peaks because if PM2.5 were the number one criterion, these would be much more frequent. A political choice …
The illustration image of this article gives you an idea of what a size of 2.5µm and 10µm represents in relation to a grain of sand and a hair. We are therefore talking about microscopic size!
Who is responsible for the quality of the air we breathe?
In terms of air quality, there are three levels of regulations that are nested within each other. The first level is the responsibility of the European Member States, the second is the responsibility of each state, and the third is at the regional level. For example, it is the regions that define the LEZs (low emission zones) linked to the system of Crit'air sticker.
Despite a trend towards improving air quality over the last 20 years, limit values are still not being respected everywhere. The French State is being sued by associations before the European Court of Justice for failing to comply with maximum levels of particles (PM10) and nitrogen dioxide (NO2) for around twenty urban areas.
How is PM2.5 measured?
A network of monitoring stations makes it possible to know in real time, almost everywhere in the world, the level of fine particle pollution. A very large number applications share this information on our smartphones.
To determine whether the atmosphere is polluted so as to alert populations, authorities follow the Air Quality Index (AQI). The AQI is calculated by taking into account the measurements of the six main pollutants. PM2.5 is the smallest measured airborn physical particle in this index., PM2.5 measurements are expressed in µg/m3, with a recommended annual average of 10 µg/m3, a target value of 20µg/m3 and a limit value of 25µg/m3.
To be more precise, European directives 2008/50/EC and 2004/107/EC are transposed into French environmental code (articles R221-1 to R221-3. See the decree of October 21st 2010 and the order of April 16th 2021 relating to the national system for monitoring atmospheric air quality.
Here are the target values for the main air pollutants according to the WHO:
When is the alert threshold exceeded?
When the alert threshold is exceeded, we speak of pollution peak.
Taking action to reduce air pollution is essential because, according to the World Health Organization, nearly 99% of the world's population breathes air that exceeds the limits set by the WHO, which threatens their health.
What are the effects of fine particles on human health?
According to Public Health France, 40,000 people die each year from air pollution. The global figure given by the WHO is 7 million. PM2.5 is designated as a group 1 carcinogen, the most dangerous form of air pollution.
People most vulnerable to PM2.5 fine particles are those with lung or heart disease, children whose bronchi and lungs are still developing, and the elderly.
When inhaled, fine particles pose a real danger because they penetrate deep into the respiratory tract to the lungs and pulmonary alveoli. They can even pass into the bloodstream. The main symptoms are irritation of the respiratory tract and eyes, wheezing, coughing and shortness of breath on exertion.
Even at moderate or low concentration levels, repeated long-term exposure to air pollution can have very harmful effects on health. Many studies demonstrate the role of pollution in reducing life expectancy and mortality. The effect is also visible in the development of cardiovascular diseases, pulmonary diseases, asthma and lung cancer.
According to Public Health France, an increase of 10 µg/m3 of PM 2.5 increases the risk of total non-accidental mortality by 15%.
Air pollution would also have an impact on the mental health. Experts from Public Health France explain the impact of pollution on the brain. "Fine particles can destroy the blood-brain barrier or enter the brain through the olfactory nerve," as well as through the part of the digestive tract that includes the stomach, small intestine and large intestine, leading to imbalances that affect the central nervous system.
What are the effects on nature and environment?
The effects of fine particles are difficult to study because of their short lifespan. They only remain in the atmosphere for about a week.
Due to nitrogen oxides (NOx) and sulphur dioxide (SO2), rain, snow and fog are more acidic. This alters the quality of soil and water through a loss of mineral nutrients leading to a complete imbalance of ecosystems.
Pollution particles blacken buildings and attack stone, which becomes fragile.
How to protect yourself from fine particles?
There are simple ventilation and prevention measures to limit the proliferation of fine particles.
- Ventilate your home for at least 30 minutes a day, except on days when outdoor pollution levels are high.
- Eliminate tobacco use at home
- Ensure that combustion appliances are properly installed and maintained
- Use a vacuum cleaner equipped with a High Efficiency Particulate Air (HEPA) filter
- Reduce the use of candles and incense
- Reduce the use of solvents and household products by choosing the most natural formulas
- Using the hood at full power while cooking
- Equip yourself with a quality air purifier in your living rooms
Is an anti-pollution mask effecient against PM2.5?
If you are a cyclist or motorcyclist in an urban area, wearing a mask becomes more than necessary because you are riding in the middle of car traffic where pollution is most concentrated.
An anti-pollution mask is useful for reducing the amount of particles inhaled. Depending on its filtration standard (FFP1, FFP2/N95 or FFP3/N99), it will filter from 80% to 99% of particles up to 0.4µm (PM 0.4). It is not a miracle object unless you opt for a professional gas mask, but it is not the same story.
To choose a good anti-pollution mask, you must also be careful to choose the right size for your face. If the mask is too big, the air inhaled will pass through the sides and not through the filters. It is recommended to avoid one-size-fits-all masks because we do not all have the same face shapes.
Frogmask anti-pollution masks combine all the advantages of a good mask for cyclists or motorcyclists:
- A very light 3D Mesh material that makes it comfortable to wear over time
- A repositionable fastening system behind the neck that does not interfere with wearing a helmet and a ponytail. It ensures an optimal seal all around the face.
- Removable FFP2/N95 filters with a lifespan of 2 to 3 weeks depending on the intensity of use and the level of pollution
- Filtration of 94% minimum of particles down to 0.4µm
- Available in 3 sizes M, L and XL
- A price under 40 euros and a one-year warranty
- 5 colours and a rather pleasant look compared to so-called “paper” FFP2 masks
PM 2.5 particles no longer hold any secrets for you. Even in our cities, much less polluted than those of Southeast Asia, the quality of the air we breathe remains a real issue. It is strongly recommended to take all necessary measures to protect ourselves because exposure to particles, even at low concentrations, can have serious consequences in the long term.
