Pigeons might get a dirty reputation from anyone who’s looked closely at the base of a statue in a big-city park, but some California carriers are doing their share to fight air pollution.

Inspired by a famous, century-old photograph of a pigeon carrying a camera around its neck, college professor Beatriz da Costa from the University of California at Irvine has enlisted the help of GPS-equipped pigeons to track and raise awareness about pollution patterns in Southern California.

The program uses custom-built, bird-sized GPS packs and Google’s satellite mapping environment to allow anyone with access to the Internet to log on to the Pigeonblog Web Site (http://www.pigeonblog.mapyourcity.net) and see the various levels of carbon monoxide and nitrogen oxides found in the air of areas traveled by the birds.

As described online, Pigeonblog aims to achieve two main goals: To raise awareness and perhaps inspire urgency around serious health issue and to promote grassroots data gathering to coordinate scientific research agendas with the concerns of citizens.

Noting that Los Angeles County perennially ranks among the 10 most polluted areas in the country, and surmising that the combination of the region’s underdeveloped public transportation and its lack of major initiatives to improve conditions were unlikely to remedy the situation anytime soon, da Costa — a professor of arts, computation, and engineering at the university, dreamed up the idea.

She enlisted the help of students and researchers to develop the sampling packs and recruited carrier pigeon fanciers to put them to use.

Each pigeon pack consists of a GPS/GSM unit with corresponding antennas, a carbon monoxide/nitrous oxide pollution sensor, a temperature sensor, a SIM card interface, a microcontroller and standard supporting electronic components including a battery. The feather-ferried payloads cost about $250 apiece (the yearlong project was underwritten by a $10,000 grant from an anonymous donor) and weigh about 1.3 ounces each.

"Designed in this manner, we essentially have developed an open-platform, SMS-enabled cell phone ready to be rebuilt and repurposed by anyone who is interested in doing so," the Web site said. "Our intent is not to support commercial applications but to encourage open-source modifications and enhancements to our freely available hardware telephony device."

Measurements are registered at ground level before takeoff and at an altitude of about 300 feet altitude as the birds reach their destinations. Fed into and processed by a central computer, localized pollution levels are visualized by color-coding and plotted in real-time on the mapping site.

Pigeons are the perfect means to collect the measurements at low altitudes, "especially in urban areas due to restrictions on airplane or other flights at low altitude in urban environments," the Web site said. "Recent behavioral studies of pigeons revealed that, in addition to the traditional theory of magnetic-field orientation, they use visual markers such as highways and bigger streets for orientation. Flying about 300 feet above the ground, pigeons are ideal candidates to help sense traffic-related air pollution and to validate pollution-dispersion models. Thus Pigeonblog has the potential of helping to validate current pollution models used by the scientific community, and we have started to explore these options with air-pollution scientists at the University of California at Irvine, using these initial releases to validate the use of such technology in this application."

The breeziness of its approach belies Pigeonblog’s intention to raise awareness about heavy topics. The site details the hazardous impact of pollutants upon young urban children, their risk factors among all-cause mortality in Los Angeles and elsewhere, and the political and economic influences which have allowed such elements to remain despite all that’s known of their dangers.

While da Costa is keeping her head out of the clouds, she nevertheless hopes that, like canaries in coal mines, her volunteered pigeons may warn folks in time.

"I doubt the Pigeonblog in itself is going to change the current situation on air pollution," she told National Geographic News. "But it might spark people’s imaginations on where it should be addressed and how easily one can gather one’s own data."