Understanding air pollution with a simple dust sensor

Outdoor air pollution, in the most extreme cases, can be immediately identified even without any special training. It casts a haze over cities, collects on streets and buildings, and provides dramatic fodder for the news. Even when the air pollution isn't actually visible, we can smell when something isn't quite right.

I previously wrote about how difficult it can be to obtain basic environmental data, and how government budget cuts are threatening air monitoring networks in several states. It now appears that other countries are making hard decisions about which monitors to keep, and which monitors to shut down. The Guardian reported recently that up to 600 air quality monitors, including monitors for nitrogen dioxide and particulate matter (PM), could be shut down across the United Kingdom.

Yet for all the attention the media pays to outdoor pollution, people spend only about 1 to 2 hours outdoors (and that's only in the pleasant summer months) according to one University of Newcastle study. According to the EPA, we spend about 90 percent of our time indoors. We spend the vast majority of our time indoors, so it makes sense monitor pollution in the home.

Indoor Air Pollution (IAP) is an especially big problem in developing countries, where 60 to 90 percent of households still rely on coal and wood for heat and food preparation. About 36 percent of acute lower respiratory infections and about 22 percent of chronic obstructive pulmonary disease (COPD) in the developing world are caused by IAP (pdf). In one study of women in China, researchers found that a 10 μg/m³ (microgram per cubic meter) increase in PM₁ (ultrafine particles smaller than one micrometer) was associated with 45 percent increased risk of lung cancer.

IAP isn't just a concern in developing and BRIC nations, though. Similar problems exist for the rural poor in the US and Canada, where indoor pollution exceeds the World Health Organization air quality guidelines in up to 80% of homes. As in BRIC nations, these homes rely greatly on burning organic fuels.

Air quality at home can be an issue even for homes that don't burn wood or coal. Indoor air pollution can come from "molds, bacteria, viruses, pollen, animal dander and particles from dust mites and cockroaches," according to the American Lung Association.

Indoor air pollution ranks among the top five environmental risks to public health, the EPA says. Indoor pollution levels may be two to five, and sometimes 100, times higher than outdoor pollution.

All that makes the indoors a great place to put a dust sensor.

DustDuino: A plan to crowdsource environmental reporting with low-cost dust sensors

A before and after photo of Shanghai inundated with smog, by Flickr's morgennebel.

There's some good news in the air. Or, well, about the air.

Last month, the American Lung Association released its 2013 report on the quality of the nation's air. The Lung Association's "State of the Air" report shows the country's air is continuing to improve.

The Lung Association attributes healthier air as a "direct result of emissions reductions from the transition to cleaner diesel fuels and engines and coal-fired power plants, especially in the eastern United States."

That much is good. But there's much room for improvement.

According to the report, "Of the 25 cities with the worst problem with spikes in particle pollution, fourteen had more days or worse problems in 2009-2011 than in the previous report." Six cities included in the report had their worst year ever (over the 14 years the report has been made) for short-term spikes in particulates.

Chicago, home to some of the dirtiest coal-fired power plants in the nation, continued to flunk both daily and annual levels of particulate pollution. This was where I did my own environmental investigation on how the Fisk coal-fired power plant threatened the health of the Pilsen neighborhood (see: "Battle in the Barrio").

The Fisk station dumped 755 tons of particulates into the air on an annual basis, according to a pollution report from the Environmental Protection Agency. The Clean Air Task Force found that the plant contributed to 15 deaths and 23 heart attacks annually, a figure based on EPA data.

The residents of Pilsen eventually won their battle, and the Fisk station was closed. EPA tests after the plant closure showed the particulate and radiation levels had returned to city-wide norms. Interestingly, one of the EPA air quality monitors was mounted in a baby stroller to measure levels around the perimeter of the plant.

Pilsen didn't have air quality monitors to begin with, though. Its residents had to lobby the Illinois EPA before the state placed an air monitor atop an elementary school in the neighborhood. The readings from the monitor led the IEPA to declare Pilsen a "nonattainment" zone for lead, a particulate which impairs the IQ, learning capabilities, and memory of children.