Experts called for stricter regulation of building and testing synthetic playgrounds amid public concerns about student health problems allegedly caused by toxic surfaces.

The Beijing Municipal Education Commission announced on Tuesday that it will work with organizations to draft and implement tougher standards for the construction and examination of school playgrounds to guarantee environmental safety for students.

The call comes after parents claimed their children attending Beijing No 2 Experimental Primary School's Baiyunlu Campus were poisoned by toxic substances emitted by the school's new running track.

However, a follow-up air quality test conducted by the China National Environmental Monitoring Center showed school facilities were safe, the district education commission said on Sunday.

Chen Jianding, a professor of materials engineering at East China University of Science and Technology, said the existing national standards, which were approved in 2011, don't set limits for all materials needed to produce and pave such synthetic surfaces.

"Glues and various additives normally used during on-site installation, which might emit toxins if improperly processed, are not included in the standard," she said.

Luo Zhenyang, a polymer material researcher at Nanjing Forestry University, said what was missed in the 2011 standards potentially opened a loophole for cheap, low-quality surface materials.

"The cost of a safe plastic surface processed with high quality materials is at least about 300 yuan ($46) per square meter, but some manufacturers offer much cheaper products containing excessive amounts of chemicals for schools with low budgets," he told China Central Television on Tuesday.

As a member of the expert panel drafting the 2011 standards, Shi Jianhua, a chemical engineer from the China Environmental Protection Association, suggested that the education authority should impose new standards specifically for school facilities with higher requirements in material safety, construction and supervision.

The Beijing Education Commission has ordered a thorough inspection of all synthetic sports fields on campuses, and has called off all construction of school playgrounds before the new standards are implemented.

Since last summer, there have been a series of similar cases reported by local media, with students suffering from symptoms such as nosebleeds, coughs and rashes allegedly caused by toxic playgrounds in about 15 cities, according to Xinhua News Agency.

In Shenzhen, Guangdong province, new standards covering the bidding process, material production, installation and post-construction testing of synthetic sports fields was implemented by the municipal education commission last month, the first time a Chinese city has imposed a tougher regional rule.

The new rule was in response to a government investigation that found 11 schools in the city used low-quality facilities containing excessive toxic chemicals.

The Shenzhen standards added seven more categories beyond the national counterpart, including quality control of raw materials and project supervision, according to the Shenzhen Institute of Building Research, a co-drafter of the standards.