Generally, in 2007 the ambient air quality in Shanghai remained the same as that in 2006. The ambient air quality was good on 328 days, four days more than in 2006, the good-air quality rate was 89.9%, 1.1 percentage points higher than in 2006. Annually, as the daily top pollutant, inhalable particle was monitored on 328 days, 89.9% of the total days of a year; sulphur dioxide, on 28 days, 7.7% of the total; nitrogen dioxide, on 4 days, 1.1% of the total; both inhalable particle and sulphur dioxide, on 3 days, 0.8% of the total; there were 2 days that both inhalable particulate and nitrogen dioxide were top pollutants, 0.5% of the total.

    The data monitored in the recent five years (2003—2007) showed that in general the rate of good-air quality kept stable and above 85% in successive five years.