The PM 2.5 index, which measures airborne particles that are less than 2.5 microns, has remained "excellent" [0-50], for a record-breaking 12 consecutive days since August 20. That day marked the start of a citywide ban on vehicles with even and odd-numbered license plates from the roads on alternate days for the forthcoming military parade. Simultaneously, the environmental protection authority implemented an inspection on volatile organic matter pollutants, the Beijing Daily reported.
The average density of PM 2.5 during those 12 days was less than 20 micrograms per cubic meter, which has decreased by 70 percent compared with the same period of last year.
