Pollution in China forces airports and highways to close

China employs coal as fuel in most of its industries. It is the world's leading consumer of coal. Thanks to this, its economic performance and its development in the markets is impressive. China's competitiveness is such that it can be said to be the first world economy.

However, not everything is development and positivity. The repeated use of coal makes the atmospheric pollution in China it is very high. It reaches such values ​​exceeded by the law that citizens must wear masks to be able to go out and not breathe the toxic air. This weekend the contamination has been so great that they have seen forced to close Tianjin airport and highways for a few hours of said city to avoid possible accidents.

Why so much pollution?

Air pollution affects cities depending on some meteorological variables such as the amount of sun that hits the surface, the wind regime, the rains, etc. Normally, the earth's surface is warmer than the air circulating at altitude. That is why hot air, being less dense, tends to rise. On days when temperatures are higher on the surface and lower in altitude, pollutant emissions rise and are not trapped in the city, so it is something less dangerous to health.

Another situation that we find ourselves in cities are windy days. If they blow up wind gusts to help disperse pollution, China will be able to breathe more polluting air. So what happened this weekend to make the pollution so high? Well, when there are cloudy days, days where the sun has barely affected the earth's surface or days in which the difference in temperatures during the day is extreme, the phenomenon called thermal inversion. That is, the hot air from the surface has risen too fast or it is simply not close to the earth's surface and therefore the air is colder. Those days when cold air dominates the surface of cities, being denser, it does not rise and creates a zone of atmospheric stability where pollutants get trapped. For these reasons, pollution in China is higher since not even thanks to rain or wind pollutants have been dispersed. 

Measures against pollution

Beijing, Tianjin and twenty other cities are in Red alert (the highest possible pollution alert) due to the high amount of polluting particles in the environment that can be breathed in by citizens. It is expected that until Wednesday pollution does not decrease, so they have been closed thousands of factories, works, traffic restrictions have been made and classes have been suspended in primary schools.

For now, Tianjin is the city most affected by smog. This smog caused by pollution reduces visibility so much that airports have been forced to close. During the hours that the airport was closed they were canceled about 131 flights.

Contamination limits according to WHO

The World Health Organization (WHO) does not advise staying for more than 24 hours in exposure to concentrations greater than 25 micrograms per cubic meter of pollutant particles of size 2,5 millimeters (called PM2,5) since having such a small diameter they are able to reach the pulmonary alveoli and generate respiratory and cardiovascular problems.

However, during this weekend the limit allowed by the WHO has been exceeded, exceeding the 1.000 particles per cubic meter. These levels of contamination are so high that they recommend not even leaving the house and closing all doors and windows.

Imagine that you have to live in a city where pollution is so high that you cannot even leave your home. That is why the atmospheric pollutants that cause so much damage to both human beings and the planet must be reduced.