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Dirty air wreaks harm long before birth
Credit: sidkid/flickr

Dirty air wreaks harm long before birth

The changes pollution inscribes in pregnancy haunt us not just during childhood, but throughout life

In chunky black glasses and a patterned scarf, her dark hair pulled back, Beate Ritz still looks more the sophisticated European than the casual Californian, even after decades in America.

Sunshine streams through a window into her home in the Santa Monica Mountains, above Los Angeles, as we speak on Skype, and she pours herself a cup of tea.

Ritz is an epidemiologist at UCLA, and she knows it can be nearly impossible to link one individual's health problem to a specifc environmental cause. But the work that would shape her career began with a nagging, personal worry. The smog blanketing L.A. came as a foul shock when she arrived from her native Germany.

She was expecting her first child, and the pregnancy was smooth and easy; she swam regularly right until the end.

So when her son was born surprisingly small, the only explanation she could come up with was that exhaust from busy I-10, which passed right above her apartment, must have been to blame.

The fear piqued her professional interest, and she began scouring research journals for hints on what the air a woman breathed while pregnant might do to her baby.

It was 1990, and Ritz was dismayed to discover there had been almost no studies on the question. Answering it would become her life's work.

But first, she had to protect her family, so she and her husband found a new home far from L.A.'s smoggy center. By the time her second son was born, they'd moved to the coastal enclave of Topanga.

He was two pounds heavier than his older brother had been.

Research and resistance

Beate Ritz. (Credit:

Second babies are often bigger than their older siblings, and Ritz knew she couldn't draw any wider conclusions. "That's anecdotal, and as a scientist you wouldn't believe it at all."

So, as her little boys grew into young men, she devoted herself to the hard, slow task of gathering the data that would invest her hunch with the authority of science.

For she knew that it is not just at the end of life, but also its beginning—before the beginning, even—that the human body is most vulnerable. She would search for the roots of disease in those early months when we are shielded from the world, our lungs not yet drawing breath.She met resistance along the way.

Some in her field doubted there could be any link between air quality and the well-being of a fetus, let alone the health of the child it would become. It was easy to believe pollution could affect a woman's lungs, the reviewers considering one of Ritz's early grant applications said, but they couldn't credit the notion that it might travel deeper within her body, deep enough to reach the baby she carried.

An early hint those judges were wrong came when Ritz learned a colleague in Prague had found the molecular fingerprint of central Europe's ubiquitous coal smoke in the placentas and umbilical cord blood of newborns.

If contaminants from Czech coal could reach growing fetuses, she knew, American car exhaust could too. The next question was, what did it do to them?

The answers, she believed, could be found in the birth certificates of tens of thousands of Californian babies and in the state's registries of congenital defects and childhood cancers.

Ritz broke out each child's vital statistics by address, then matched the addresses against local air pollution levels. The analyses took weeks to run on the computers of the 1990s, but got quicker as the technology gained power.

Eventually, she found what she was looking for. She tells me how, gradually, she discovered one ailment after another was more prevalent in the children of mothers who had breathed dirty air while pregnant.

The particular worry that had started her on this path was borne out: Underweight babies were 10 percent more common for women living near heavy traffic. So were premature births; worse still, extremely premature births were 80 percent more likely. Those findings have serious ramifications, because prematurity and low birth weight are both linked to health problems later in life. Ritz found risks of pre-eclampsia, a potentially serious pregnancy complication, increased with pollution levels too.

When I ask whether she now blames pollution for her own son's small size, her reply reflects the scientific rigor that has always guided her: "It's unknowable."

From percentages to people

Los Angeles smog. (Credit: Maciek Lulko/flickr)

Other researchers have linked miscarriage and infertility to pollution.

That latter fact touches a painful scar for me, a reminder of the years we spent, and the endless medical appointments, trying to conceive the second child I'd always imagined having, the brother or sister that my daughter Anna never got.

It's a sadness I've mostly put behind me now, grateful for the healthy, happy kid whose mom I do get to be. But there was a time, not so long ago, when stumbling across a study linking infertility to the kind of pollution my husband and I have breathed for years might have sent me back down a fruitless trail of anger and grief.

London's air, of course, may have had nothing to do with our troubles, with the lost dream of that longed-for baby. Some things, as Beate Ritz says, are simply unknowable.

That unknowability, the statistical language in which pollution's dangers are inevitably framed, unmoored from any one life, strikes me as yet another reason they are so hard to grasp. Because we don't care, really, about percentages.

We care about people, the people we live with, the people we love. So air pollution has a statistically significant relationship with infertility, with cardiovascular disease. What do I do with that? Is it why I have one child, not two? Did it cause the heart attack that terrified us, years ago, but from which my father, thank-fully, recovered fully?

There are no answers to those questions. Most of us are not epidemiologists, trained to accept such uncertainty. But so many of the risks in our complicated world present just like this: real, and well documented, shouting for our attention from the headline of a story someone posts online. Yet intangible, diffuse, impossible to pin down. It's a strange, and very modern, kind of anxiety.

That is not to say, of course, that the statistics don't matter. When it comes to air pollution, they matter immensely, even when the danger appears, at first blush, to be small. Because the unforgiving logic of mathematics means that when even an innocuous-sounding, single-digit bump in risk is spread over an entire city, region, or nation, more people will draw an unlucky hand than when a health gamble whose odds look scarier is taken by a smaller group, like those who smoke or drink heavily.

Ten percent may not sound so bad, but if an extra 10 percent of all babies in the polluted parts of L.A.—or Louisville, or Lagos—are born early, as Beate Ritz found, that adds up to a lot of premature babies.

Because we all breathe tainted air, billions of us, just about everywhere, even a tiny upward tick in the incidence of a given ailment translates into vast numbers of victims.

The only mystery, really, is who they are.

The findings grow more troubling

Credit: Brian Dewey/flickr

When the time came to present her first findings, Ritz worried how her colleagues might respond.

"I was scared to death to have reviewers tell me again that the fetus does not breathe, and what was I doing," she recalls.

As it turned out, she got the opposite response. Scientists were waking up to pollution's dangers, and they were eager to hear what she had found.

And while Ritz did her work, others had begun similar studies.

"Within a few years, it really mushroomed and you could find papers from all over the world reproducing what I've seen in L.A."

Many of those studies have been done in China, a nation now engaged in the painful task of grappling with dirty air's effects on its children. As Ritz pressed on, her findings grew more troubling.

Low birthweight and early arrival are relatively common. Cancer in children, thankfully, is rarer, so she had to draw on nearly two decades of records to draw firm conclusions. She concentrated on those diagnosed at five or younger, the cases in which, if a connection to some prenatal exposure existed, it would be easiest to trace.

What she discovered was chilling. Pediatric leukemia, kidney cancer, eye tumors, and malignancies in the ovaries and testes of young girls and boys were all more common in children whose mothers breathed traffic exhaust during pregnancy.

Diving deeper into the records, she found, too, that babies' death rates—from breathing problems and the unexplained tragedy of SIDS, sudden infant death syndrome—climbed along with pollution levels. Ritz had tied the exhaust floating from millions of tailpipes to the worst kind of grief.

She found, too, that heart malformations—tiny, imperfect valves and aortas, holes in the cardiac wall—were three times more common in the children of mothers who had lived with pollution early in pregnancy, when the fetal heart is taking shape.

More recently, Ritz added a new wrinkle to the struggle to understand the causes of autism with her finding that women who breathe polluted air while pregnant are more likely to have an autistic child.

“We are a whole. Only we have weaknesses.”

Credit: David Baker/flickr

Scientists examining dirty air's effects on adults can look to the bodies of mice and other lab animals to unpick the mechanisms of harm.

But those creatures' pregnancies are too dissimilar to ours to offer useful insights, so we know little about exactly how pollution's damage is wrought in utero. Its invisible work may be done as early as the days after conception, when two sets of DNA twist together into one. Toxics might penetrate tiny, developing organs a bit later.

Or they could interfere with development indirectly, by sparking reactions in the mother's immune system that have a domino effect on the growing baby. It's entirely possible that the changes pollution inscribes before birth haunt us not just during childhood, but throughout life. It would take decades-long studies to illuminate such connections. And of course, with every year that passes come other experiences and exposures that contribute to the onset of illness, making direct links to prenatal life hard to untangle.

But the groundwork that the nine months of gestation, and the first years of childhood, lay for the sickness and health of a lifetime is a burgeoning area of research. Scientists are starting to ask whether airborne toxics might wield their power in slow motion, creating a hidden susceptibility that lies dormant for decades, until it is touched by some fresh exposure or trauma.

Even those of us apparently unaffected by what we've breathed, in other words, may not have escaped the consequences.

We just haven't felt them yet.

I tell Ritz how surprised I've been by the sheer range of illnesses linked to dirty air, the terrifying variety of the marks it leaves on us.

"It's not surprising to me," she replies. "If you see it all as independent effects on different diseases," then each one is a new, and shocking, piece of news.

But if you look at the bigger picture, the interconnected nature of the human body and all its systems, it makes more sense.

"We are a whole. Only we have weaknesses. And I guess the disease we get is the one where our weakness kind of overwhelms our defenses."

This is excerpted from Choked: Life and Breath in the Age of Air Pollution, being published this month by the University of Chicago Press.

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