The Indoor air pollution sources

Air pollution is a complex and constantly evolving mixture of chemical, biological and physical elements. These components can be toxic to humans and, knowing that every day we inhale up to 20,000 liters of air, if they contain pollutants it can have effects on human health.

Atmospheric pollutants can be produced by human activity, it will then be called anthropogenic pollution, or it may be linked to natural activity, for example the products of the volcanic activity, soil erosion, sandstorms, or also natural pollution that can be produced by the oceans.

In the case of human activity, all kind of activity can produce atmospheric pollutants: industrial activities, road transport but also air and rail transport. Domestic activities and in particular heaters (fuel, wood etc.) will produce pollutants and of course all agricultural activities ...

Pollutants observed in the atmosphere are not all emitted directly from these sources. They also result from physico-chemical reactions between chemical components (primary pollutants and other components of the atmosphere) driven by weather conditions.

In order to have a good understanding of the pollutions' phenomena to be able to elaborate forecasts, a thorough knowledge of the pollutants, their sources, the quantities emitted by each pollutants' source over long periods (the year) and the geographical distribution of emissions is necessary. All of these variables are varying considerably according to the different periods of the year, and even at different times of the day.

There are now many numerical models of air quality, they incorporate inventories "Spatialised" pollutant emission data. These inventories identify the quantities of pollutants emitted by the different sectors of activity.

In France the Interprofessional Technical Center for Studies of Atmospheric Pollution (CITEPA) is the reference Agency in charge of the realization of national atmospheric emission inventories which are reported in international conventions (CLRTAP, UNFCCC in particular).

The regional inventories are carried out under the responsibility of the AASQA (Authorized Associations of Air Quality Monitoring), and a national spatialized inventory (INS), carried out by the Ministry in charge of the environment which was born in 2013. The NSI identifies the emissions of more than fifty atmospheric pollutants with spatio-temporal resolutions of up to the hour and the km2 respectively.

The indoor pollution.

The indoor pollution is made of many different pollutants whose source is the crossroads of our activities with the components of our environment.

Outdoor air, including local pollution, pesticides, pollen and various dusts. The houshold equipment, the furnishing, the household appliances. Building materials and decorations, glues, varnishes, paints and insulation. And, human activities such as DIY, cleaning and cooking with the ways in which locals are occupied, pets and plants.

Fine particles.

PM2.5 fine particles with a diameter of less than 2.5 μm have an impact on mortality and cardiorespiratory morbidity. Various chronic diseases (cancers, cardiovascular and respiratory pathologies) develop after several years of exposure to particles, even at low levels of concentration. Other effects are more and more highlighted: possible effects on reproduction, risk of premature birth, impaired neurodevelopment of the child, dementia in the elderly ... At present, particles are pollutants for which the effects on health are the most documented.

The effects of pollution on health

If it is an exposure of a few hours to a few days ( acute, so-called short-term exposure) to this pollution: ocular or respiratory irritation, asthma attacks, exacerbation of cardiovascular and respiratory disorders that may lead to hospitalization, and in the most severe cases at death;

If it is a question of exposure of several years (chronic, so-called long-term exposure) to air pollution; the health effects in this case can be defined as the contribution of this exposure to the development or aggravation of chronic diseases such as: cancers, cardiovascular and respiratory pathologies (asthma, chronic obstructive pulmonary disease, heart failure), neurological disorders, etc.

In France, chronic exposure to air pollution leads to impacts the most important health effects and the share of health effects attributable to pollution peaks remain very low (source: ANSP).The preponderant health impact of air pollution is due to year-round exposure to average levels of pollution and not to peaks.