BEIJING, April 14 (Xinhua) -- To curb air pollution, Hebei Province, Beijing and Tianjin will enforce a unified standard to reduce the use of coatings and adhesives in construction.

According to the standard issued Thursday, the amount of volatile organic compounds (VOCs) must not exceed set levels in manufacturing, storage and in use of construction coatings and adhesives. The measure is estimated to reduce VOCs in the air by 20 percent.

The Beijing-Tianjin-Hebei region sits at the heart of the North China Plain where air pollution, particularly winter smog, often occurs as a result of the high concentration of industrial and vehicle emissions, static air circulation and the burning of coal.

"VOCs are a key component of the ozone and PM2.5 -- fine particulate matter with diameter smaller than 2.5 micrometers," said Yu Jianhua, chief engineer of the Beijing Municipal Environmental Protection Bureau.

He said that rapid urbanization had led construction coating and adhesives to constitute a major part of VOCs in cities. In 2015, 5.16 million tonnes of construction coating was consumed nationwide, an eight-fold increase since 2000.

Yu said Beijing had its rules on the use of coatings and adhesives but the latest standard upgraded restrictions and widened the jurisdiction to cover Tianjin and Hebei where rules had been more relaxed.

The standard is the first jointly-issued rule for the three areas to fight air pollution.

By 2017 the region must cut PM2.5 density by 25 percent from 2012 levels, according to a government action plan issued in September 2013.

Beijing has been struggling to reach its target of an average PM2.5 density of 60 micrograms per cubic meter. In the first three months, its PM2.5 density averaged 84 micrograms per cubic meter.

However, Beijing's air quality is already ranked the best among 28 cities in the three areas.