What are pm2.5 fine particles?

pm2.5 written on a blue background on fine particles

Today we're talking about air pollution, with a focus on fine particles PM 2.5

At R-PUR, we are convinced that a global understanding of air pollution would make it possible to change mentalities more quickly.

We are therefore keen to simply explain what these invisible and odorless particles are which do a lot of damage to our body.

You can also find our complete file to easily understand air pollution .

What is PM2.5, definition and measurement?

Particulate matter or PM (Particle Matter in English) is a physical particle: it is therefore defined by a size (unlike a gas)

It is more commonly called a fine particle because it is very small.

You could thus observe it with an entry-level microscope: its size is between a bacteria and a red blood cell .

PM2.5 fine particle diagram

On a daily basis, to determine whether the atmosphere is polluted, we base ourselves on the AQI which is an air quality index.

The AQI is calculated by taking into account the measurements of the six main pollutants: PM2.5 is the smallest measured suspended physical particle in this index.

What are fine particles
and where do they come from?

You can now visualize what PM2.5 suspended particles represent, the question now is to know where they come from .

Before continuing, it is important to remember that there is not just one PM2.5.

Indeed, when we talk about fine particles, we classify them by size, so they can come from different sources and not look the same if we were to compare them under a microscope.

They are formed from a complex mixture of solid and liquid particles of organic and mineral substances suspended in the air.

More simply, they mainly come from France:

  • wood heating
  • road transport, particularly diesel vehicles
  • industries

Now that we are able to better situate them, what are their effects on human health , in the short and long term.

What does the World Health Organization (WHO) say about these effects?

In recent years, we have known more precisely the effects of these suspended particles on human health.

PM2.5 is so fine that it can lodge deep in our lungs .

They do a lot of damage to our body: even at low concentrations, small particle pollution has a health impact.

Among the long-term causes:

  • 60% cardiovascular accidents
  • 20% COPD: chronic respiratory disease
  • 10% lung cancer

They also cause short-term damage to our body:

  • Cough
  • Itchy eyes
  • Sore throat

PM2.5 measurements are expressed in µg/m3 , with a recommended annual average of 10 μg/m3 by the World Health Organization (WHO)

AirParif tells us that in 2018, this regulation was exceeded for around 10 million inhabitants in Île-de-France, or 85% of Ile-de-France residents (between 14 and 18 µg/m3 near road traffic)

Air Parif - Paris - PM2.5

Source: City of Paris with Airparif

However, there have been positive things in recent years, the level of PM2.5 particles in the atmosphere has been falling and we have observed fewer episodes of intense pollution on average over the year.

Where does France stand in terms of European regulations?

France is the bad student when it comes to PM2.5: in 2018 it released no less than 164,000 tonnes of PM.25, the largest total in all of Europe.

When we carried out this in-depth study, we were surprised as this figure seemed enormous to us given the size of a PM2.5 pollutant.

We are convinced that information accessible to as many people as possible will enable the collective awareness necessary to make the air breathable for future generations.

We can also note one more positive side: by slightly changing our consumption habits, France could meet the objectives set by the WHO in terms of regulations by 2030 .

For example, road traffic tends to decrease with the progression of soft mobility such as cycling in our cities: we could then have a direct impact on air quality on average over the year.

How to filter PM10 and PM2.5 fine particles? What about anti-pollution masks?

When air quality is not good, such as during episodes of pollution or pollen , more and more people affected by the problem seek to protect themselves.

They can then turn to an anti-pollution mask.
Two essential parameters must be taken into account:

. Effectiveness : what pollutants will my mask filter and to what size.

. Hermeticity : in other words, will outside air enter my mask.

For example, if 40% of the air were to enter your mask, which is the most efficient in the world, there would not be much point in wearing it in the middle of road traffic.

At R-PUR, we have therefore developed a solution that perfectly meets these two criteria :

We filter particles with a size of 50 nanometers (PM0.05) or 50 times smaller than PM2.5, so the efficiency is there.

In terms of airtightness, depending on the shape of your face, we will filter between 99.86% and 99.98% of the outside air: we can therefore assure you, you will be warm in your mask.

In the short term, all effects of coughing and irritation will disappear.
As for the long-term effects, your body will thank you.

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