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Haze Does not Mean Air Pollution



By Zhou Hongchun, DRC


A clear definition of haze is needed to avoid people’s confusion. In 2005, the meteorological departments introduced the standards relating to haze observation and forecast level, stipulating relevant quantitative indicators including visibility, particle concentration, extinction and humidity. In general, fog and haze are weather phenomena with reduced visibility, but their humidity, particle sizes and light extinction principles are not the same. Nearly harmless to humans and other creatures, fog is a phenomenon of diminished visibility as a result of the light extinction caused by water droplets and ice crystals. Haze formed by human activities can be called “dust haze or smoke”, such as London Smoke, Los Angeles Smoke and similar incidents.

The study of measurements and causes of the haze and PM2.5 need to be deepened. Not knowing the relationship between haze and pollutants and shutting down enterprises as the main means to control haze will lead to misjudgment of enterprises’ performance. Only by making a precise definition of “haze” can we find corresponding solutions and take targeted policies to control air pollution with a relatively small cost.

Both meteorological and environmental protection departments are responsible for releasing early warnings of haze and severe air pollution. In some areas, early warnings are released after some consultations are made between the two departments. If the probability of “fog” is used to predict “haze” or even release early warnings, it is redundant or completely unnecessary. Each department should be accountable for their own responsibilities. The meteorological department should forecast the probability of fog weather, while the environmental protection department should give early warnings after the looming up of fog weather. The environmental protection department should take various measures for better results including shutting down pollution-incurring enterprises, restricting the number of cars on road, and suspending students’ classes so as to effectively strengthen the control of pollutant discharge.