The 24-hour average data of PM2.5, an important gauge of air quality, was released by the Beijing Municipal Environmental Protection Bureau on its website, Beijing Times reported.

The bureau started to publish hourly readings of PM2.5 before the New Year, which helped to measure the effect of fireworks during the Spring Festival, the paper said.

The hourly data doesn't indicate the overall air quality of the day and it's easier for the public to judge the air quality with the 24-hour average data, analysts said.