Definitions for the conditions which qualify a day in China as having haze pollution have been announced by the country’s Ministry of Environmental Protection. The main indicator of haze pollution is PM2.5 particles and they have a diameter of 2.5 microns and are capable of penetrating the lungs.
It has been reported that a haze pollution day happens when the average concentration of the PM2.5 surpasses 75 micrograms per cubic meter, while visibility becomes less than 5 km for over six hours straight. This happens mostly due to an increased concentration of fine particulate matter found in the air. The new criteria says that Guangzhou recorded haze pollution for 14 to 15 days in 2013. Moreover, Beijing reported 138 days with haze pollution, while Shenzhen did not have any.
A technical standard which has been published in 2010 by the China Meteorological Administration stated that haze pollution occurs when visibility in the country becomes less than 10 km because of the factors other than dust, precipitation and sandstorm, which means that Guangzhou recorded 51 haze pollution days in 2013 alone.
In November, 2013, the ministry released an instruction which asked local governments to set up emergency management systems in order to tackle haze pollution. However, local governments in different regions use various guidelines to define haze pollution.
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