China to implement national standard for PM 2.5 masks
China's first national standard for common protective masks was released on April 25 by the Standardization Administration and the General Administration of Quality Supervision, Inspection and Quarantine.
The official document for the standard, which mainly focuses on the factors of protective effectiveness and safety performance, will come into effect from Nov 1, this year.
Protective effectiveness can be represented by four different levels of PM 2.5 concentration, which refers to airborne particulate matter with a diameter of 2.5 micrometers or less, which is hazardous to human health.
The A level is effective in stopping PM 2.5 at 500 micrograms per cubic meter; B level can protect against 350 micrograms per cubic meter; C level protects 250 micrograms per cubic meter; and D level protects against PM 2.5 at 150 micrograms per cubic meter.
To satisfy the safety performance requirement, every protective mask should be manufactured within the stipulated maximum amount for formaldehyde, dye and microbes according to the national standard.
The national standard is not available for children as the detailed medical and experimental data for their respiratory resistance is yet to be collected.