Our cities are polluted?

The pollution is mainly in large cities or industrial sites, but it varies in time and space. Since the 70s, there was a significant improvement in air quality and pollution are some way of 'be controlled. These include pollution by sulfur in most French cities. But today, most of us are exposed to pollution from cars and road transport. The proximity of many industrial sites is affected by discharges from factories. In space, air quality varies even within the city. It is rather good in protected areas and places where traffic is low. It becomes bad when you are in an area of significant traffic.
Other factors can affect the air quality. Examples of weather. How about the air quality? By the ATMO index ranging from 1 (excellent) to 10 (horrible), which gives an average over the city. It is calculated from the measured concentrations of major pollutants like sulfur oxides, nitrogen oxides, ozone and particulates. Moreover, the development of networks for measuring air quality, will in future to better understand the state of pollution and its distribution.

What are the effects of air pollution on health?

The air is essential to life, but it can have harmful effects if the quality is bad. Pollution is an immediate danger to health, but also an effect that is amplified over the years. The people most sensitive, such as children, the elderly, heavy smokers, people with heart or lungs are most affected by air pollution. For them, the pollution may promote disease, aggravate some, and sometimes even hasten death. The effects of pollution on health increases with concentrations of pollutants in air and duration of exposure . That is why it is advisable for sensitive people, if pollution episode, limit their physical exertion, not to leave their homes and, of course, to quit. It is possible to ask their doctor if concerned about her health or that of those children. The regulation defines certain indicators of pollution, levels of reference to guide public policy. These limit values and alert thresholds.

Air pollution: poor fetus!

The pollutants in the air, especially those from combustion processes (traffic, heating), would impair fetal growth. The birth weight babies and their head circumference would be thereby reduced. The long-term consequences of these disorders, as well as biological mechanisms by which these pollutants could affect the development of unborn baby, were misidentified. This work, conducted by researchers at The mixed INSERM-Université de Grenoble 823 "Institute of Oncology / Development" in collaboration with the CHU de Nancy, Poitiers and researchers from Inserm U780, Villejuif, were recently published in the journal Environmental Health Perspectives.
The study involved 280 pregnant women in the cohort EDEN mother-child, in whom fetal growth was followed at the end of each trimester of pregnancy and birth. In mid-pregnancy, the volunteers wore a device to quantify the levels of benzene in ambient air. With this, it was possible to obtain data from individual exposure to air pollutants. And this work has to take into account women's exposure to pollution, not only outside but also in their homes, their workplace or in transport.
The researchers found the influence, already known, the duration of pregnancy, maternal corpulence and passive smoking on fetal growth. Adjusting for these factors, they showed that the effect on head circumference was evident from the late second trimester. The association between air pollution and fetal growth was observed for women in the general population, exposure levels often encountered in the French cities of medium size. These results confirm those of an earlier study conducted by the same team, but for which pollution data were from measurements in outdoor air without taking account of direct exposure to pollutants in indoor air. According to these researchers, air pollution could affect some biological functions of pregnant women, limiting exchanges between mother and fetus, and therefore alters the growth of the latter.

Changes in chemical characteristics of air.

Air pollution can be produced by - the fumes - the combustion heaters providing domestic and urban - the exhaust from automobiles (1) and all engines - The burning of waste outside of the planned facilities therefor; - The flight in the wind products stored without special precautions.
These different sources of pollution sent into the air of dust and gases more or less dangerous. The various dust, particles of unburned carbon, living germs (bacteria, mold spores, etc..) Can accumulate over some cities and thus form a sort of gray cap to float altitudes between 1 500 and 2 500 m and can absorb some solar radiation (20% in summer and 50% in winter).

Noise pollution

Noise pollution is more dangerous than was believed by those who are not direct victims, or are unaware of the physiological and psychological disorders which is the origin and occur more or less long term. The characteristics in decibels Environmental noise can be analyzed in relation to references provided by the "barometer of noise." Barometer of 120 dBA noise Plane on the runway. 110 Orchestra Pop music. 100 Breaker (1 m) Motorcycle full speed (7 m). 90 former Metro Truck (7 m). coffee grinder mixer (60 cm). 80 Carrefour animated. 70 Conversation loudly seen at 50 cm. Residence near a highway . 50 Conversation perceived to 3 m window closed on a busy street. 40 room stay calm. 20 Rustling leaves.

The air pollution: emissions to concentrations

The air pollution is characterized by the presence of atmospheric gases or particles that cause a change which may have adverse effects on health or the environment. Emissions of gases and particles are of natural (volcanic eruptions, decomposition of organic matter, forest fires) or human (industry, transport, agriculture, residential heating ...). In the atmosphere, these substances undergo various changes under the effect of weather conditions (wind gradients temperature ...). It follows other pollutants and geography of pollution emissions of different origin. Pollutants called "primary" pollutants emitted directly by sources: nitrogen monoxide, sulfur dioxide, carbon monoxide, dust, heavy metals, volatile organic compounds. To these are added pollutants "certificate" from physico-chemical properties of gases under the influence of special weather conditions: ozone, nitrogen dioxide ... concentrations of pollutants in the air are monitored by devices measurement and analysis.