Chemists at The Ohio State University recently enjoyed an unplanned opportunity to finely examine the contents of dust, and the results should be of interest to air purifier users as well as health researchers. The chemists found no fewer than 63 different types of particles making up the dust specimen. The scientists were actually testing a new metal-mesh sensor designed to study the mixture of electrons and photons, when dust clogged the device. Only then did they realize their equipment could measure the component particles in the dust. The most common ingredient they found was “organic” material, followed by quartz and man-made chemicals including air pollution, fertilizers and construction materials.

What kind of “organic” material? The researchers weren’t sure, but promised a follow up study. Many people believe that indoor dust contains mostly dead skin cells. But in fact dust mites, pet dander, pollen, viruses and mold spores are more common indoor air pollutants that are biological. Mechanical air purifiers are effective at removing any of these, but of course only if the contaminants are suspended in the air. Some particles settle on carpets or upholstery and these cannot be removed by an air purifier until they are kicked up into the air by activities such as vacuuming or people walking across the carpet.

Cyclists, meanwhile, are worried about another recent study that indicated cyclists are exposed to twice as much black carbon from vehicle exhaust than were pedestrians. Black carbon is a form of particle pollution formed by the combustion of fossils fuels, and is linked to increased risk of cancer, heart disease, allergies, asthma and other respiratory illnesses. The researchers factored out other possible causes, including age, distance walked/cycled, lung function or even amount time time spent exercising. This is not good news for urban cyclists – at least until someone invents an air purifier that fits on handlebars. Researchers from the London School of Medicine told Reuters news service suggested that seek out alternative routes away from traffic.

The cyclists levels of black carbon in sputum samples were 2-3 times higher than the pedestrians. The researchers speculate that cyclists breathe more deeply and faster than pedestrians in traffic.