Made by French company R-Pur, the mask has been made available through crowdfunding site Indiegogo and is designed primarily for cyclists and motorbike users, through the company also says it could be useful for runners or other urban athletes too. It filters out harmful air pollutants like toxic particles, fine particles and diesel, pollen, and viruses and bacteria using a nano filtration system, working on particles that are between 10 microns and 0.04 microns in size. This makes it one of the most effective air filtration systems out there, as most European protection masks only filter particles of down to 0.4 microns in size.
For reference, a grain of sand is about 90 microns in size, a human hair is 50-70 microns, dust and pollen particles are 10 microns, fine particles caught by conventional masks as 0.4 microns, and the R-Pur mask filters all the way down to nanoparticles of 0.04 microns.
The filtration system works through a replaceable filter, and in addition has an active carbon layer which should absorb harmful Volatile Organic Compounds (VOC) and gases. When you breathe out, the hot air is channeled downwards to prevent your goggles and visor from becoming misted, a particular concern for motorbike riders.
There was a cool update to the mask on display at CES 2019 too — a prototype illuminated version of the mask that had lights on the side which changed color based on the current air quality. The mask also connects to a smartphone app which can inform you about air quality conditions, and lets you know how long the filter is expected to last and when you might need to change it. The makers estimate that the filter will need to be changed every one to two months depending on its usage.