Pigeons may look like pests to some Londoners, but the prolific city birds have found a new purpose - today marks the first day of the capital's new pigeon pollution patrol.
Air quality monitoring firm Plume Labs has partnered with Twitter UK and DigitasLBi to launch a flock of pigeons equipped with "little backpacks" - the company's exact words - carrying ultra-light pollution sensing technologies.
The birds - named Coco, Julius and Norbert - will be used to track air quality all over London, and if you tweet your area to @PigeonAir you will receive an instant air pollution level report. The pigeons' flights can also be tracked online and for the truly dedicated there's even a mobile app.
"Air pollution is a huge environmental health issue," said Romain Lacombe, PlumeLabs chief exec, adding that, according to a study by King's College London, air pollution kills almost 10,000 people in London every year.
"Putting air sensors on the back of pigeons goes beyond raising awareness of this problem and helps Londoners understand the impact of pollution in an accessible, tangible and immediate way," Lacombe said.