Rapid urbanization will inflict heavy damage to public health, if the officials responsible for planning and urban development, will not take into account measures to combat air pollution.
This is different Beijing smog and without... (Photo Peter Barwick.)

This prevents the report prepared by the world meteorological organization (WMO), in collaboration with the International project to study the chemistry of the atmosphere (IGAC) and presented at the Open science conference IGAC on atmospheric chemistry in the anthropocene, held in Beijing (China). The most striking moment of the document Fox, Jalkanen, head of the research Department of the atmosphere WMO, calls the rate of growth of mega-cities (Metropolitan areas with a population of over 10 million) in developing countries.

In the world there are already 23 cities giant, while 60 years ago there were only two. Slightly more than half of humanity now lives in cities, and by 2050, when the urban population is projected to almost double this percentage probably will be close to 70%. "Almost all of this growth will come from developing countries," stresses Mrs. Jalkanen.

"City-giants able to offer better jobs and education and a well-planned, densely populated areas can reduce the need for development of new lands and to use energy more effectively," said Luisa Molina, President Malinovskogo of the center for strategic studies on energy and environment (USA).

"But many cities in developing countries are expanding rapidly and are planned poorly, and measures to reduce pollution are rarely accepted, - reminds researcher atmosphere Zhu Tong from Beijing University (China). - This has serious impacts on the environment and human health".

In Asia, for example, has more than half of the most polluted cities in the world, and air pollution leads to a half a million deaths a year, according to a recent report by the Asian development Bank. More than two thirds of Asian cities (in the rest of the world is only one-fifth) does not meet the standard of air quality European Union on the amount of solid particles.

"Part of the problem is the speed of development", - tells Mr. Zhu. Since 1950, the urban population of China has increased by almost five times, which led to exorbitant growth of energy consumption and brought out on the streets millions of cars. Beijing smog has become the byword.

The number of air pollutants responsible for respiratory diseases and heart, in Beijing high and continues to grow. Over the last three decades, the concentration of ozone at ground level has increased sixfold, and the current level, as a rule, twice the rate of, certain by the U.S. Department of environmental protection (EPA), according to researcher atmosphere David Parrish from the National Directorate of studies of the ocean and atmosphere (USA).

The concentration of PM2.5 - aerosols with a diameter of 2.5 microns or less - in the air of Beijing usually varies from 100 to 150 mg/m3, which is 6-10 times higher than normal EPA. "The health impact can be enormous," says ecologist Andre Nelson of the University of California in Los Angeles (USA). According to one estimate, the mortality rate in cities increases by 1% with growth in the number of PM2.5 per 10 ug/m3, adds the scientist.

In February, the State Council introduced a law aimed at limiting the levels of ozone and PM2.5, and other emissions. Rules that you want to come by 2016, similar to that of the United States and the European Union, and in some cases even stricter. This step in 1996 was preceded by the statement, which helped significantly reduce emissions of sulfur dioxide and carbon monoxide due to restrictions on vehicle emissions and encourage the use of natural gas and low-sulfur coal, says researcher atmosphere Shao Ming from Beijing University.

"In order to meet the new standards (particularly for ozone and PM2.5), will require strategic changes measures to reduce pollution," emphasizes Mr. Shao. Unlike sulfur dioxide and carbon monoxide, that are directly emitted by sources, ozone and PM2.5 - secondary pollutants: they are created by chemical reactions between various predecessors in the atmosphere. "This means that we have to throw a wider network instead of focusing on several predecessors", - the expert says.

In Beijing there are strict control of emissions, but a substantial part of the pollutants coming into town from the surrounding areas, says Mr. Zhu. During the Olympic games of 2008 in Beijing, for example, the contribution of air masses from the South in peak ozone concentrations are reached 34-88%. "The quality of the Beijing air can be increased only in the case if it will be possible to overcome the administrative border", - believes the expert.

The conference participants called on other large cities of developing countries to follow the example of Beijing. "Otherwise town giants will be the main source of global pollution, " says Ms. Molina. - How governments cope with the problems of rapid urbanization, will determine the quality of life in the future."

Based on the materials of Nature News.