Our battle with air pollution is not just above ground, it is also under; pollution on underground transportation, e.g. London Underground (LU), can be 20 times* higher than roadside air. The primary pollutants are particulate matter (PM) 2.5 and 10, which are many times smaller than a strand of hair. They are hence tiny enough to enter our body to cause damage. Damage equivalent to smoking a cigarette^ if you spend just 20 minutes underground.
Iron oxides form majority of the pollutants and are typically produced from the interaction between train wheels and tracks. PM concentrations are affected by particle resuspension a phenomenon where PM at rest are disturbed and recirculate back into the air. This is due to trains and the train tunnel piston effect, as well as people’s movement.
Inspired by how Nature uses rain to clean the air, Airtomo wearables and modules release dry, atomised water vapour to remove pollutants¹ through a process called aggregation. Water droplets bind harmful particles to form large, heavy aggregates which fall to the ground, thus removing PM from the air. They no longer resuspend, even after water has evaporated, and can subsequently be removed with a mop or broom.
Airtomo proposes a decentralised, dynamic way to purify air. The infrastructure modules leverage on the train tunnel piston effect to push vapour into station platforms to clean the air and directly tackles resuspension at the source when it is installed along passage ways, intersections, entrances or exits. Airtomo wearables offer individuals a personal vapour cloud that actively cleans the air one breathes or reduces resuspension induced by foot motion. In addition, Airtomo consumes nominal resources². Most importantly, the process is visually tangible, thus motivating adoption.
*Financial Times, 2019.
^British Lung Foundation, 2003.
¹A single atomiser cleans 167 litres of polluted air in a minute.
²A single atomiser consumes 23ml of water per hour and utilises 1.5W of power. Airtomo wearables house between 30 to 50ml of water. This capacity is based on the average travel duration taken by LU commuters – 1 hour.