Summary | "In 2017, Beijing had 226 days of good air quality,
increasing from 176 in 2013," Liu said.A day with an average
Air Quality Index of 100 or below is considered to have good
air quality.The year also saw large reductions in other
pollutants, especially sulfur dioxide.The national standard for
PM2.5 is 35 micrograms per cubic meter.| People's Daily Online ...
increasing from 176 in 2013," Liu said.A day with an average
Air Quality Index of 100 or below is considered to have good
air quality.The year also saw large reductions in other
pollutants, especially sulfur dioxide.The national standard for
PM2.5 is 35 micrograms per cubic meter.| People's Daily Online ...
en.ce.cn | 04 January 2018