‘Dust’ a cosmic read Hannah Holmes’ book looks at small matter

THE SECRET LIFE OF DUST: FROM THE COSMOS TO THE KITCHEN COUNTER, THE BIG CONSEQUENCES OF LITTLE THINGS, by Hannah Holmes, John Wiley & Sons, Inc., New York, 2001, $22.95.

Dust. Can’t live with it, can’t live without it. But ignore it and you’ll end up on the dust heap of history.

Actually, all of us will end up as speckles in the great cosmic dust heap – along with our dusty neighbors and the dusty Earth itself – according to Hannah Holmes in her surprisingly interesting science book.

Tackling a subject that seems less than fruitful at first glance, Portland resident Holmes makes the case with irreverent humor and solid reporting that dust is “terrifically consequential.” She weaves a thread of environmental concern throughout the book, spotlighting unforeseen consequences of our society’s headlong industrialization and the interconnectedness of every corner of our planet.

Along the way, we learn about golden rivers of desert dust circling the Earth, and about “luckless” kangaroo rats spiraled aloft by powerful dust devils. Holmes introduces us to scientists with arcane occupations such as dust scholar, aerobiologist, and “Doctor of Sand.” She explores the Serengeti-like world of headless dust mites and their fearsome “pseudoscorpion” predators in our carpets, beds and sofa cushions.

Why is lowly dust so important? The answers lie in the very largest to the very smallest aspects of our universe. Nearly five billion years ago, space dust from exploding stars coalesced into the sun and planets. Other-worldly dust still rains down on us at the rate of more than 100 tons a day, made up of “diamonds and sapphires, inky-black carbon and rich organic molecules … tiny reminders that we, along with every other bit of life on Earth, are part of a very long and extraordinary story.”

Dust is everywhere, both large (pollens, sand) and tiny (fungal spores, tobacco smoke), in quantities difficult to comprehend. Each of us is enveloped in a “personal cloud” of dead skin flakes – we shed some 50 million each day – and dust encountered inside and outside our dusty homes. Every breath we take contains 150,000 to a million dust specks, the signature of a constantly disintegrating world.

The author distinguishes between natural and manmade dusts. Some are beneficial, some are harmful, and some are a perplexing combination that still defies scientific explanation. Natural dusts include the 3 billion tons of desert dust that take wing annually, 31/2 billion tons of salt flecks rising from the oceans, and molds, pollens, bacteria, fungi, viruses, insect parts, soot from forest fires and rock dust from erupting volcanoes.

Man-made dusts have evolved in quantity and deadly sophistication from the cooking fires of our early ancestors, to smokes rich in microscopic beads of bronze, iron, and copper produced by metalworking, to invisible fragments of animal and plant fibers from spinning and weaving, to the industrial revolution’s bounty of toxic dusts and smokes from fossil fuel burning. And, finally, graduation to the “miscellaneous dusts of the 20th century: nerve-wracking mercury and stupefying lead; carcinogens from dioxin to polychlorinated biphenyls; the radioactive dusts of nuclear disasters; pesticides, asbestos, and poisonous smokes.”

The benefits of dust? You might count the formation of the solar system, and of our own bodies, made up of complex molecules forged in supernovas and recycled from every living thing that came before us, including dinosaurs and Attila the Hun. Without dust, water vapor wouldn’t condense into clouds until the relative humidity reached 300 percent, and raindrops and snowflakes would have no seeds. Metal-rich sand from the Sahara, riding the high winds over millions of years, laid down bauxite deposits on coral-based Caribbean islands that are now the source of many of our aluminum cans.

Unfortunately, it’s easier to catalog the many threats from dust. Holmes mentions coral reefs in the Florida Keys decimated by a fungus in airborne desert dust; evidence of DDT in houses 20 years after it was banned; industrial and agricultural dusts which cause asbestosis and black lung; harmful cooking dusts that produce high lung cancer rates among Chinese women; allergies caused by dust mite manure. One even has to worry about scented candles with lead wicks, and “baby powder overdose” that can lead to respiratory failure in infants and, possibly, ovarian cancer in women.

In the gray area between the harmful and beneficial effects of dusts are two timely examples. One is the alarming increase in asthma among children in the United States, which some experts have attributed to the modern soup of dusts and chemicals steadily building up in the environment. Now there’s an intriguing new theory: that children are not being exposed to enough dust in our too-clean, too-tight houses to condition their immature immune systems.

The other example is the effect of dust on climate. It wasn’t until recent years, Holmes points out, that satellite photography revealed the ever-changing rivers of dust high in Earth’s atmosphere. Scientists now suspect that this dust plays a significant role in global climate, including the advent and retreat of ice ages. But the mechanisms are maddeningly complex. Without dust, clouds don’t form, and clouds reflect sunlight to keep things cooler. Too much dust also alters the climate picture, with light-colored dust reflecting sunlight and black soot holding heat. Clear as mud? Supercomputers are trying to sort it all out.

Holmes handles the science with impish, quirky wit and an arsenal of obscure statistics that make you wonder how in the world she uncovered them. And be warned: this is not your father’s New York Times sort of science writing. She’s a deft wordsmith who has mastered the art of online science writing and caters to short attention spans.

A prolific magazine travel writer and contributor to NPR’s “Living on Earth,” Holmes is perhaps best known for her “The Skinny On …” science pieces for the Discovery Channel Online. Her subjects have included “Why Asparagus Makes Your Pee Stink,” “Lunacy and the Full Moon,” and “Why There’s No Channel 1 on TV.” More serious pieces took a look at sunscreen testing and the origin of sonic booms.

“The Secret Life of Dust” offers some worthy take-home messages, not the least about our own mortality and the eventual, fiery fate of the Earth as the dying sun bloats into a red giant and consumes the planet. Holmes tells of humankind’s attempts to delay their “dustification” through mummification or freezing, and of those whose cremated remains have been packed into firecrackers or launched into space.

“There will be no exceptions to the rule,” she reminds us. “Dust thou art, and unto dust shalt thou return.”

Luther Young works as a scientific grant writer at The Jackson Laboratory in Bar Harbor. Between 1987 and 1991, he worked as a reporter at The Baltimore Sun, four years of which were spent as that newspaper’s science writer.