Beltway, even during off-peak hours. More shocking, though, I
recorded equally high values in my kids’ school parking lots, where
cars and buses idle waiting to pick up students gathered outside.
Nineteen percent of Americans live near “high-volume” roads, and
most cities don’t monitor these corridors for air quality.
Regardless of your income, the closer you live to these roads, the
higher your risk of autism, stroke and cognitive decline in aging,
although the exact reasons haven’t been teased out. Many scientists
suspect it has something to do with fine particles causing tissue
inflammation and altering gene expression in the brain’s immune
cells. “I hold my breath when I’m behind a diesel bus,” said Michelle
Block, a neurobiologist who studies pollution’s effects on microglial
cells at Virginia Commonwealth University. It’s all another reason to
spend time in the woods.
It makes sense that if some nasally routed molecules are bad for
the brain, others might be good. We’ve known for millennia that
smells can influence our moods, behaviors and health. Aromatherapy,
or using fragrance specifically to help heal the sick, dates back to
ancient Egypt. Cleopatra, that clever girl, reportedly used rose petals
to lure Marc Antony to her bed. On a less legendary scale, retail
stores and consumer product manufacturers know how to exploit the
nose-brain connection. In the words of the academics who study such
things, pleasant smells trigger “approach behavior.” If a store smells
good, we’ll walk in and linger. In one study, participants cleaned their
lunch area more assiduously if they smelled citrus. Even Windex
changes our behavior. People assigned to a room sprayed with the
pungent cleaner expressed a greater willingness to volunteer and
donate money to a cause than participants in a neutral- smelling
room. The hypothesis is that the smell of “cleanliness” makes us
aspirational. Who knew: Windex is the smell of virtue.
When we say we can smell spring, we are really smelling tree
aerosols. As the air temperature heats up, so do the biochemical