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Particulate count PM 1, PM 2.5 and PM 10.

Nobody with smoke, possibly suspended particles

Particles are fragments in liquid or solid form that are suspended in the air. These particles can be of natural origin (erosion, volcanism ...) or of human origin (smoke, wear, etc.). They can remain more or less in the atmosphere according to their nature. They are produced during the combustion of fuels and during industrial processes in other. These dusts contain many organic compounds such as sulphates, nitrates, polycyclic hydrocarbons ... They can also be composed of metals such as lead, zinc, cadmium. A considerable part of the particulate matter (PM) concentration results from human activities, mineral dusts, wind-blown agricultural soils, VOCs from vehicles, industrial processes and solvents, sulphates and nitrates from power plants and transport. Natural particle emissions include forest fires, wind-blown dust, some mineral particles, natural nitrogen oxides (NOx) and some VOC emissions.

Total particles (PT) are atmospheric particles with a maximum diameter of about 100 microns. These particles are usually retained by the upper respiratory tract of the respiratory system (nose, mouth) in humans.

PM10 refers to particles of 10 micrograms per cubic meter or less in diameter (micrometers). PM10 is generally subdivided into a fine particle fraction of 2.5 micrograms per cubic meter or less (PM2.5) and a coarse fraction of particles greater than 2.5 micrograms per cubic meter. PM10s are called "respirable particles or fine particles" and are found near roads and dusty industries. They are breathable and they can penetrate the bronchi.

PM2.5 are "fine particles" present in smoke and fog. They can be issued from forest fires, for example. They are also formed when gases emitted by power plants, industries and automobiles react in the air. These particles can penetrate the pulmonary alveoli.

PM1 are "very fine particles" that can pass the alveolar-capillary barrier. They have a diameter less than 1.0 micrometer.

Particles larger than 2.5 microns are coarser and fall back quickly. The thinner ones can stay in the air longer. It is recognized that the finer the particles, the more they can be harmful to health since they can go further inside the body.

Exposure to these particles can cause various health problems, including more severe heart and respiratory diseases such as asthma, bronchitis, emphysema ... Children, the elderly and people with respiratory disorders are particularly sensitive. Other toxic air pollutants can bind to particles already in the air, creating additional health risks. Particles can also damage vegetation, materials and buildings. When particulate matter is deposited on metals, wood, stone, painted surfaces and fabrics, it may cause discoloration, in addition to the physical and chemical degradation of these materials. Particles, along with other air pollutants, help reduce visibility and increase smog. They can accumulate on plant surfaces and infiltrate the soil, increasing the plant's vulnerability to disease.

The particles were classified in three (3) categories, primary particles, secondary particles and resuspended particles. The primary particles are emitted directly into the atmosphere by an emission of anthropogenic or natural type. Secondary particles come from a physicochemical reaction from other pollutants. Finally, the resuspended particles are particles that have settled and return to the air after a movement of air.


The potential genotoxicity of nanomaterials. It is not yet possible to collect, quantify and analyze nano particulate contaminants. For a strictly informative purpose, we make available a French article that deals with this subject. It is now recognized that workers are exposed to a set of particles present at a nanoscale. The nanoscale is defined as a size of 1 to 100 nanometers (nm). In occupational hygiene, it is common to differentiate between manufactured nanoparticles (NP) and ultrafine particles (PUF) that come from "natural, human or industrial sources such as a portion of fumes from forest fires, cigarettes, engines, Combustion or welding operations "nanoparticles are therefore produced for industrial purposes while ultrafine particles are unintentionally produced during industrial activities.

Artistic representation of particles suspended in the air

In France, the Environmental and Occupational Health Safety Agency had already identified several hundred consumer products containing nanomaterials: textiles, cosmetics, food, sports equipment, building materials. At the global level, in 2005, if $ 10 billion was spent on research and development in the field of nanoscience and nanotechnology, only $ 40 million was spent on research on potential side effects. In other words, only 0.4% of global spending went to risk research. "In 2008, the IRSST also reported that more than 650 products with nanoparticles were already on the market. , the list of Woodrow Wilson Center for Scholars had more than 1,300 marketed products incorporating nanoparticles in its online inventory. Today in 2018, it is now more than 2600 globally recognized products marketed containing nanoparticles, this number has quadrupled in ten years.