BEIJING -- Air quality in Beijing has improved in the first five months of this year, with the density of PM2.5, a major pollutant particles down by 19.3 percent year on year, local environment watchdog said on Thursday.

The capital saw 96 days with sound air quality during the five months, 21 days more than in the same period last year.

The density of sulfur dioxide, nitrogen dioxide and PM10 went down 28.8 percent, 12.9 percent and 20.9 percent respectively.

The Beijing Municipal Environmental Protection Bureau said that it will continue to reduce the use of coal and take high-emission vehicles off the roads, among other measures, to improve air quality in the city.