The sources of particles or “aerosols” are numerous and varied, due to the many different processes by which they are formed. Methods of classification of these sources are based on origin (anthropic, marine, biogenic, volcanic) or on the processes of formation. A distinction can be made between two types of aerosols:
primary aerosols: those emitted directly into the atmosphere in solid or liquid form. The majority of particles related to human activity stem from the combustion of fuel (for production and transformation of energy, heating for individual homes principally using biomass, etc.), automobile transport (exhaust, wear, friction, etc.) as well as agricultural activities (cultivation of the soil, etc.) and very diverse industrial activities (foundries, glass factories, grain silos, incineration, quarry operations, public works, etc.) Their size and composition are highly variable.
secondary aerosols: directly formed in the atmosphere by processes of transformation of gases into particles, for example sulphates (transformation of sulphur dioxide) and nitrates. The majority of organic particles are secondary aerosols.
PM10 is the category of particles whose diameter is less than 10 micrometres (inhalable fraction). PM2.5, or very fine particles having a diameter of less than 2.5 micrometres, travel more deeply into the respiratory system.
Depending on their size distribution, the particles penetrate more or less deeply into the bronchial passages. The smallest particles may, at relatively low concentrations, irritate the lower respiratory tract and impair lung function as a whole. Some particles have mutagenic and carcinogenic properties.
Effects on the environment
The soiling of buildings and monuments is the the most obvious environmental damage
The reference standards
Information and recommendation threshold for sensitive individuals
Alert warning threshold for the general population
Atmo Normandie is an association for monitoring air quality.It belongs to the national organization , is member of ATMO France Federation and approved by the French ministry for ecology.
Among its missions : providing measurement, expertise, advice and information.