Beijing authorities say they will start publicizing more precise data on the city's air quality, after a public outcry that the government was understating pollution levels.

The Chinese capital currently bases its air quality on particles of 10 micrometers or larger, known as PM10, and does not take into account the smaller particulates that experts say are most harmful to human health.

The Beijing Environmental Bureau said Friday it will start releasing data based on smaller particles known as PM2.5 ahead of the Lunar New Year, which starts this year on January 23.

When a thick smog blanketed Beijing last year, forcing the cancelation of hundreds of flights, official data showed the air was only slightly polluted. But figures published by the U.S. embassy in Beijing ranked the air quality as “very unhealthy.”