Air pollution


The environmental impact is most known air pollution due to exhaust gases, which cause respiratory diseases and contributes to global planète. With domestic heating appliances, the automobile has become the main cause of smog urban chronic situation in Asian capitals. According to the French Agency for Environmental Health Safety (AFSSET), air pollution, due to nearly a third of voitures to polluting discharges, would be responsible for each year of the death of 6 500 to 9 500 in France.

Major releases of automobile exhaust sont:

>>>Carbon dioxide CO2 contributes to the greenhouse effect, global warming and a changing climate, but is not a pollutant within the meaning of a toxic or irritating gases.

>>>Carbon monoxide (CO). It causes headaches, dizziness, blurred vision and decreased blood oxygenation. At high concentrations, it is deadly, hence the danger of leaving an engine running at idle in a closed garage. It is quickly diluted and degraded CO2 atmosphère.

>>>Nitrogen oxides (NOx). In humans, this irritant gas decreases immune defense and impairs lung function. It is the precursor to the formation of ozone in the lower layers of the atmosphere, by its decomposition in the presence of sunlight. Ozone is an irritant gas and toxic at high concentrations.

>>>Unburned hydrocarbons (HC). In humans, they cause respiratory diseases and allergies. They are the other precursors to ozone formation.

>>>The suspended particles from combustion in diesel engines. Soot particles, for example, increase the risk of respiratory disease and possibly cancer, according to studies épidémiologiques.

>>>Sulfur dioxide SO2. In countries where the sulfur content of fuels is little or no limited, it is a major contributor to acid rain.

>>>Lead. In countries and regions where the addition of lead in gasoline is not prohibited, a large proportion (between 65 and 99% of children living in areas at risk, and about 50% even among those less exposed) would be poisoned lead so chronique. The introduction of unleaded gasoline in developed countries is rapidly indeed resulted in a decrease of about half of the blood lead levels in urban adults, although less susceptible to lead absorption than children..

Benzene. Road transport in general are by far the largest emitters of benzene, and found in Europe a direct link between the decrease in maximum benzene content in fuels (halved in 2000) and a decrease in the concentration of bottom of benzene in atmosphère.

These discharges are subject to regulations in different countries, such as European emission standard Euro for Europe. These standards are attached to standardized driving cycles, such as NEDC or American counterparts to represent a typical driving behavior. The thresholds adopted by these regulations fall steadily over the years.

For a given model, a petrol car consumes more fuel than diesel volume for gasoline has an energy density lower than diesel. But also the thermodynamic efficiency of a gasoline engine is less Almost all drivers observe intakes higher than those measured under standard driving cycles in fixed, yet those who are used commercially.