It's hard to get too worked up about dust. Yes, it's a nuisance, but it's
hardly one that causes us much anxiety —and our language itself suggests as
much. We call those clumps of the stuff under the bed dust bunnies after all,
not, say, dust vermin.
to get worked up 为某件事生气；不开心
clumps of 一团一团的
dust bunny 积尘；灰兔子（关于灰尘的比较萌的说法）
But there's a higher ick factor to dust than you might think. And there's a
science to how it gets around —a science that David Layton and Paloma Beamer,
professors of environmental policy at the University of Arizona, are
get around 传播；散播
Layton and Beamer, whose latest study has been accepted for fall
publication in the journal Environmental Science &Technology, knew a lot
about their subject even before they set to work. Historically, everyone from
chemists to homemakers has tried to figure out just what dust is made of, and
the Arizona researchers drew their preliminarydata mostly from two studies of
household dust conducted in the Netherlands and the U.S. The American survey in
particular was a big one, covering six Midwestern states. Layton and Beamer also
included a localized study in Sacramento, Calif., that focused particularly on
lead contamination. What all those surveys showed was decidedly
figure out 理解；解决；计算
The specific dust mix in any household differs according to climate, age of
the house and the number of people who live in it —not to mention the occupants'
cooking, cleaning and smoking habits. But nearly everywhere, dust consists of
some combination of shed bits of human skin, animal fur, decomposinginsects,
food debris, lintand organic fibers from clothes, bedding and other fabrics,
tracked-in soil, soot, particulate matter from smoking and cooking, and,
disturbingly, lead, arsenicand even DDT.
"There are more [components]," Beamer says. "Dust is a hodgepodgeof all
sorts of things. It would probably be impossible to make a list of all the
But dust's ingredient label is not the whole story, since all of those
flecks and bits behave differently and present different levels of health risk.
To investigate those factors more closely, Layton and Beamer developed a
computer algorithmthat looked at the size, source and toxicityof dust particles
as well as how easily they enter the house, if they ever exit and, if so, by
what route. That information, by extension, can provide at least a rough sense
of the dust load in your own home.
As a general rule, the majority of household dust —about 60% —comes from
outside, through windows, doors, ventsand, significantly, on the soles of your
shoes. Smaller dust particles —from 28 to 49 microns, or thousandths of a
millimeter —tend to stay on your shoes. The rest is shaken off inside. A higher
share of the dust that floats in the air gets deposited, but again, there's a
lot that determines how much any one home will get.
"Here in Arizona," says Beamer, "where we leave our windows open most of
the year and have an aridclimate, we would probably have a higher ratio."
Industrial centers or sootycities have plenty of dust too, though for different
arid adj. 干旱的；不毛的
ratio n. 比例
There's not much to fret about in simple particles of dirt or organic
materials such as pollen(though they can trigger allergies), but lead,
arsenicand DDT can be a more serious matter. About one-third of the arsenic in
the atmosphere comes from natural sources —volcanoes principally. The rest comes
from mining, smelting, burning fossil fuels and other industrial processes. Even
in relatively low concentrations, arsenic is not without risk, especially to
small children who play on the floor and routinely transfer things from their
hands to their mouths. The same is true for lead, which comes less from wall
paint —the source most people would expect —than from auto exhaust, smelting and
soil deposits. "Lead loading on floors is a key determinant of blood-lead levels
in children," Layton and Beamer wrote in their paper.
fret about 因……焦急；为……烦恼
particle n. 颗粒；微粒
pollen n. 花粉
low concentration 低浓度
determinant adj. 决定性的 n. 决定因素
The fact that DDT is still in house dust is a surprise to most people,
since the pesticide was banned in the U.S. in 1972. But a house is a little like
a living organism: once it absorbs a contaminant, it may never purge it
completely. "Dust in our homes," says Beamer, "especially deep dust in our
carpets and furniture, is a conglomerateof substances over the life of the home
and can provide a historical record of chemicals that have entered it."
contaminant n. 污染物；致污物
purge v. 净化；清除
The mess that originates within the home is a lot easier to measure and
control. The more people who live there, the more skin that's going to be shed,
the more pets, the more animal fur. And, as Mom always warned, the more you walk
around the house while eating, the more food debris you'll drop on the floor
—which also attracts more insects that will die, decompose and add their own
special zestto your dust. Cooking smoke and tobacco smoke, which are the most
obvious contributors when they're being produced, actually make only a small
contribution to what winds up on floors and surfaces. The tiny size of the
particles makes them likelier to rise and adhere to other surfaces or simply
remain in the air than to settle.
shed v. 散发；流出
wind up 卷起；扬起
It goes without saying that your home will never be dust-free, but there
are ways to reduce your own dust loading —and it's important that you try. Dust
mites, which feed on shed skin, produce allergensthat are known triggers for
people suffering from asthma. Same goes for cockroach dust, especially in
cities. No one needs much convincing about the wisdom of getting rid of arsenic,
and the good news is that about 80% of it can be removed simply by cleaning
floor dust regularly.
it goes without saying 不言而喻；不消说
None of this means that dust poses a clear and present danger or that you
need to take any extraordinary measures. Just clean regularly, don't smoke, eat
at the table —and try not to freak out. Dust bunnies are still only bunnies; you
may just want fewer of them.
freak out 吓坏了；崩溃