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.
