国家环保部首次对灰霾污染日给出详细定义，并正在公开征求意见。未来该标准将适用于全国城市或区域范围内的灰霾污染日判别与预报。
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A haze pollution day occurs when the average concentration of PM2.5 is above 75 micrograms per cubic meter and visibility is less than 5 km for more than six consecutive hours due to an increasing concentration of fine particulate matter in the air.
灰霾污染日指细颗粒物 此次国家环保部给灰霾污染日 近两年来，雾霾(smog)天气频频造访国内各大城市，防雾霾口罩 相关阅读
“雾霾险”被叫停
雾霾导致“停课”
“雾霾”笼罩京城
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