Airborne pollution falls into two major categories. There's careless, casual contamination (some of it being created halfway across the globe and wafting our way) caused mainly by noxious emissions. And then there's the cruel, calculated kind—the sort that's on our minds continually in this age of threatened stateside terrorism. Sufficiently fast, high-resolution detection of both varieties depends on new kinds of sensors.
While Rufus Edwards, who researches environmental health at University of California, Irvine, says (in a Seed magazine article) that mobile sensors are hugely promising for improving public health, he also notes that, "the greatest obstacle is funding, not finding the proper tools." That's rather ironic, because "electronic noses" are more cost-effective than ever.
The article currently featured at Sensors Online focuses on detecting intentional pollution unleashed by sinister evildoers. It describes the limitations of "portal" systems (such as those commonly installed in airports), and illustrates a vision of more complete security using low-cost, fast-responding distributed or portable monitors. It details the operation of sensor arrays able to discriminate among various compounds, and explains how to overcome the effects of interferents—an issue that is important and tricky, but ultimately solveable.
Another article, from the new-ish science magazine Seed, tells of two projects designed to get a higher-resolution handle on the less calculated but still dangerous variety: careless, casual contamination.
People and Pigeons Against Pollution
This past autumn, researchers from the group Preemptive Media undertook a project, Area's Immediate Reading (AIR), which equipped volunteers in New York City with binocular-sized sensor packs able to detect the indirect greenhouse gases carbon monoxide (CO) and nitrogen oxide (NOx). While it's true that the Environmental Protection Agency monitors NYC's air quality, the agency uses just 14 sensors to cover the entire city and thus provides sketchy detail.
The AIR sensors take measurements every second while an integrated GPS reveals the location of the reading. The unit sends the data to AIR's server, which displays it on a map (accessible via the Internet) that also highlights the location and emission statistics of major polluters.
In another project, called PigeonBlog, racing pigeons carry similar sensors while a Web site tracks their readings in real time.
The Seed article quotes Brooke Singer, co-founder of Preemptive Media and assistant professor of New Media at SUNY-Purchase: "We are making that kind of invisible background more visible."
Global Remedy Needed
It's great that low-cost sensors can help us understand the problem of careless pollution. Now we just need some sort of technology to actuate a remedy.
A recent installment of PBS's NewsHour reported that Chinese officials routinely ignore government mandates to halt construction on industrial plants—to the detriment of residents surrounding the facilities, who have been found to exhibit higher than usual incidents of cancer and other serious diseases. And perhaps to our detriment as well; according to the EPA, on certain days nearly 25% of the particulate matter above Los Angeles can be traced to China.
It's no wonder. China's air pollution campaigners have put together this photo gallery illustrating the problem's effects, and in this image of eastern China Beijing is completely blocked from view by air pollution. A recent study by a Chinese research institute found that 400,000 people die prematurely every year in China from diseases linked to air pollution.
Low-cost, portable sensors may be able to give us extremely localized information about air pollution, but we need a global solution to overcome it.