Airtomo is a small clip-on device that can be attached to a bag, pocket or shoe, and comes in a series of bold colours.
Chiam has created a working prototype for Airtomo and is developing concepts for purifiers in ankle and neckband form.
According to the designer's research, pollution levels on the London Underground can be 20 times higher than levels in roadside air.
Airtomo works by releasing atomised water vapour into the air. This ultra-fine mist of water droplets binds to particulate matter in the air, forming a heavy aggregate that drops to the ground.
Particulate matter is the microscopic particles such as soot that create air pollution and has been designated a major health risk by the World Health Organisation.
"I am fascinated with biomimicry and discovered that nature uses rainwater to clean dirty air," Chiam told Dezeen.
"That insight seeded the idea of using atomised water to remove harmful particulate matter."
The water vapour is fine enough that it doesn't get the user's clothes damp, explained Chiam, and the pollution particles on the floor can then be swept away.
"Atomised water droplets evaporate almost instantly at that size on the Tube, or under normal to low humidity conditions," he explained.
"The merit of seeing the vapour is that the cleaning process becomes tangible and perceptible. With that said, the challenge is to convince commuters that prolonged exposure to the vapour cloud would not result in wet clothing."
Designed to be used on the go, Airtomo is charged with a micro-USB cable and can be replenished with water wherever necessary.
Chiam also plans to make Airtomo modules that can be placed on the walls in underground train stations to improve the air quality.
A small scout module would detect movement from passing commuters using a passive infrared sensor. After receiving this information via WiFi, the main module would release water vapour into the air.
After conducting interviews with commuters, Transport for London and air-quality experts at Plume Labs, Chiam has created a prototype Airtomo and is looking for partners to help bring it to market.
Chiam undertook the project as part of the Innovation Design Engineering Master's course that is jointly run by the Royal College of Art and Imperial College London.
More air purifier design includes a portable air purifier that uses a nanoparticle filter to break down pollutants and this electronic face mask by LG.
Images are by Kevin Chiam unless stated.