How do we improve the quality of air we breathe around busy roads?
A British entrepreneur says he's come up with a plan.
Thomas Delgado has designed a device that sucks in polluted air, cleans it, then pumps it back into the atmosphere.
Called the Pollution Solution, it has ducts, or 'pod heads', buried in the surface of the road which sucks fumes through to an air station at the side of the road.
Inside, there are filters that clean the air to 99% purity.
(SOUNDBITE) (English) CEO OF POLLUTION SOLUTION, THOMAS DELGADO, SAYING:
"It's proven that this is a worldwide health crisis and the fact that there is no proactive solutions being brought forward I think is very saddening. Although we are moving to a fully electric world in the future, in terms of automotive, in the interim we still have a lot of fossil-fueled vehicles driving around on roads, polluting streets and effectively killing people."
The system needs to be connected to a power supply.
And at a busy London junction, filters would need to be replaced about once every three months.
In Cambridge, they're using artificial intelligence to try and improve air quality by improving traffic management and reducing congestion.
A network of sensors monitors vehicles - classifying, counting, recording speeds and tracking path data.
The Vivacity system - being trialled in 20 locations across the UK - identifies interactions between pedestrians, cyclists and cars.
Dan Clarke from Cambridgeshire County Council says with 36,000 new homes planned in the county over the next 15 years, congestion will get worse without drastic action.
(SOUNDBITE) (English) CAMBRIDGESHIRE COUNTY COUNCIL, SMART CAMBRIDGE PROGRAMME MANAGER, DAN CLARKE, SAYING:
"We hope that as we go forward we can give people better information as they come into town. We are also looking at expanding our sensor networks to collect more data and apply the work we've done already across the city."
Air pollution kills around seven million people globally every year, according to the World Health Organization.
Possible solutions to reduce that figure are beginning to emerge.