Dandruff May Be Significant Air Pollutant

Forget the hair spray cloud. Dandruff and other dry skin cells may account for a much larger proportion of air pollution than previously thought.

A new study suggests that particles of skin, pollen, fur fibers, and other cell fragments may account for up to 25 percent of the particles in the atmosphere.

Particles suspended in the atmosphere, known as aerosols, play an important role in climate change. But researchers say they need a better understanding of what those aerosols are made of so they can build more accurate climate change models.

Aerosols produced by burning fuel and other human activities have been the primary focus of attention for their contributions to air pollution and climate change. But aerosols from natural sources such as plants and animals, known as “bioaerosols,” have been considered a minor source of air pollution until now.

Natural Air Pollutants?

In the study, which appears in the current issue of the journal Science, researchers analyzed aerosols collected from different environments and in different seasons.

They identified a broad array of bioaerosols in the samples, including fur fibers, dandruff, and skin as well as fragments of plants, pollen, spores, bacteria, algae, fungi, viruses, and protein crystals.

In some cases these natural air pollutants accounted for up to 25 percent of the total particles in the atmosphere.

In spring, the results showed that pollen is more abundant, and in winter, dead skin and other cells are the predominant sources of bioaerosols.

However, the findings suggest that the overall prevalence of bioaerosols doesn’t appear to vary seasonally despite the expectation that concentrations would be higher in the summer than in winter. Researchers say that lack of variation may be due to redistribution of particles during dry winter months.

By Jennifer Warner, reviewed by Michael W. Smith, MD

SOURCE: Jaenicke, R.Science, April 1, 2005; vol 308: p: 73.