Air filters that greatly reduce air pollution could be mass-produced using materials called metal–organic frameworks (MOFs).

MOFs are porous crystalline materials containing organic 'struts' and metal ions, and can capture large amounts of fine particulate matter electrostatically. Bo Wang and his colleagues at the Beijing Institute of Technology heated three kinds of MOF crystals and applied them individually to substrates including fabric, foam and plastic using two hot rollers. In lab tests, the resulting filters reduced the levels of hazardous 2.5- and 10-micrometre-wide particles in air by up to 99.5% at room temperature, with a loss of efficiency of only a few per cent at 200 °C.

Potential applications for the filters include household vacuum-cleaner dust bags and vehicle exhaust pipes.

Adv. Mater. (2017)