Pigeon Air Patrol in London

@ CNN

It could seem like a bird-brained idea: relying on a team of pigeons to carry out scientific studies on air quality. But chances are, you've never seen a squad of pigeons wear backpacks quite like this.Meet London's Pigeon Air Patrol, a flock of "superbirds" measuring nitrogen dioxide in a city with some of the highest levels of air pollution in the world.

Almost 9,500 people in the English capital die prematurely each year due to long-term exposure to polluted air, according to a report last year by King's College London. Globally, the number of air pollution-related deaths is closer to 7 million, a 2014 World Health Organization report said.Now a team of 10 trained pigeons is taking to the skies strapped with 25-gram sensors to measure the harmful emissions not always visible to the naked eye -- and, rather aptly, are tweeting the results.

Londoners can ask their feathered friends to track nitrogen dioxide levels in their area by tweeting @PigeonAir. The clever creatures, with a little help from researchers at Plume Labs, will then tweet back their readings, ranging from "moderate" to "extreme."

One of the pigeons -- which have names such as Norber, Coco and Julius -- will also be strapped with a GPS tracking device. A vet will be on hand to monitor the birds' well-being over three days of flights.The winged patrol was originally dreamed up by Pierre Duquesnoy and Matt Daniels of marketing agency DigitasLBi as part of Twitter's #PoweredByTweets competition last year, winning the "Solve a Problem" category. The patrol aims to boost a much larger campaign by Plume Labs to recruit 100 Londoners to carry out their own pollution monitoring -- though this one will be on the ground.