BEIJING, Sept. 3 (Xinhua) -- The average concentration of PM2.5, an air pollutant, in Beijing was 23 micrograms per cubic meter in August, which hit a record low compared with the same period in recorded history, the Beijing Municipal Ecological Environment Bureau announced Tuesday.

The city's average concentration of PM2.5 (particulate matter less than 2.5 micrometers in diameter) between January and August also hit a record low of 42 micrograms per cubic meter, according to the bureau.

The capital city saw 227 good air quality days in 2018, 51 days more than 2013, said Yu Jianhua, deputy head of the bureau, adding the density of other air pollutants including sulfur dioxide also hit a record low.

The continuous decline in the density of air pollutants reveals the improvement of the ecological environment in Beijing, according to the bureau.

The city's coal consumption was down 87 percent from its peak in 2005 by the end of 2018.