There are a number of atmospheric pollutants by chemical composition, size and different concentrations. Depending on their chemical and physical characteristics may be more or less harmful to the human body and for the global climate. For this reason, some substances, such as ozone, nitrogen dioxide and sulfur dioxide, are monitored more than others. One of these pollutants that is taking on increasing importance and which, in a few years, the law should establish the limits for release into the atmosphere, is the so-called Black Carbon.
The Black Carbon particulate, a dark brownish color composed primarily of carbon, is the product of the incomplete combustion of fossil fuels or biomass, such as wood, agricultural waste or manure. For example, it is emitted by diesel engines and the old home stove prevalent in underdeveloped countries (Nepal, India, etc.).
The Black Carbon belongs to the family of climate-controlled compounds short-lived — the so-called SLCF (short-lived Climate brute Forcers) remains in the atmosphere for a few days, not decades as for carbon dioxide. Although it remains in the atmosphere for a short time and is present at a concentration of 2 or 6 orders of magnitude lower than carbon dioxide, Black Carbon is a significant contribution to global warming, especially in Arctic regions reached from Black Carbon particles.
In these regions the effects of soot are amplified: its dark colour, in fact, makes a strong absorber of solar radiation; as a result, once deposited on snowy or icy surfaces, it decreases their albedo effect by increasing the temperature and thus dissolving more rapidly the ice or snow.
Some researchers are also studying the function of the brown clouds, formed by the interaction of particles of Black Carbon with other present in the atmosphere, Earth's radiative budget.
From the point of view, the particulate matter of Black Carbon belongs to the family of PM10, or more precisely to the PM 2.5, since it has a diameter of less than 2.5µm. This characteristic makes it very harmful to the human body, because its magnitude is such as to be able to penetrate deep into the lungs. Therefore prolonged exposure to Black Carbon-rich gases can result in respiratory diseases.