A hand-picked flock of 20 pigeons will be released in August to monitor air pollution over the skies of California, according to a report in the New Scientist.

The idea was developed by Beatriz da Costa, a researcher at the University of California, who described the technique as "combining an air pollution sensor with a homemade cellphone".

Each pigeon will be fitted with a backpack equipped with GPS satellite tracking and air pollution sensors. A miniature camera will capture and post aerial views.

The kit will enable the pigeons to communicate information on air quality levels via text messages to an online pigeon 'blog'.

A prototype of the pigeon's flight gear is already in production, although plans to fit all the necessary equipment into a such a small backpack are still underway.

The pigeons are scheduled to take off on 5 August from San José in California.