The Price of Ignorance and the Cost of Neglect: Science,Air Pollution,and Politics

“There is power and beauty in learning how to reckon with numbers,” writes Devra Davis, a much-honored and highly productive epidemiologist in When Smoke Ran Like Water, her unique and important narrative study of air pollution and human health. “Properly understood, numbers can tell us stories of the conditions that shape our lives, our deaths, and even the sex and health of our children. If we know how to listen, numbers can tell us the truth.”

Devra Davis listens to numbers. As an epidemiologist, she has studied numbers that make compelling connections between toxic and hazardous pollution and a variety of impacts on human health for more than three decades. Davis is extremely concerned about what she has seen in these numbers. Based on her own assessment of a wide set of sources, Davis's book argues that the better that environmental epidemiologists have come to understand their own statistical models and develop increasingly sophisticated measures of health and the impacts of environmental factors, the more sophisticated the purveyors of potentially harmful materials have become at raising questions about findings and politically avoiding having the questions be asked in the first place.

Davis's love of numbers is made all the more compelling because she is a gifted and compassionate writer whose ability to find her own threads of personal meaning and individual connection to each of the episodes she narrates adds a wonderful literary polish to what might otherwise be complicated or abstract findings. Her primary contention is that too many questions have yet to be asked about the connections between toxic substances of all sorts and human health. The shreds of evidence we do have, however, can be pieced together into a troubling narrative: We are poisoning ourselves and we are putting human health at risk on a global scale.

In ten chapters grouped into three major parts, Davis provides a historical and contemporary study of epidemiological knowledge about air pollutants. In part one, “Ancient History,” Davis shows how statistical modeling revealed elevated deaths and increased sicknesses in Donora, PA during a toxic fog event in 1948. She also explains to us how similar modeling techniques revealed an even more serious impact from a toxic fog event in London during 1952–1953. In both instances, no one had bothered to measure the effluents or profile the constituents of the fog so an accurate preventive response was difficult.

When automobiles changed the landscape and atmosphere of Los Angeles in the 1950s, new state-level energies were directed toward understanding connections between human health and the emissions of automobiles and industry. These state level political efforts resulted in studies and recommendations that became models for federal clean air legislation in the 1970s. Throughout the 1970s, the EPA took a powerful role in setting standards and developing legislation based on the kinds of epidemiological studies pioneered in California. Davis describes how for a brief and contentious few years, it appeared that public health was going to be taken seriously by the public sector. Unfortunately that did not last.

In part two, “The Best of Intentions,” Davis shows how corporate America honed its defenses, and learned that sometimes studies are better left undone and even those that are done, perhaps contain too much uncertainty to be taken as causal proof of anything. Researchers like Davis continued to build evidence and arguments making statistical links between smoking and cancer, or raising awareness about new elevated levels of breast cancer, or establishing correlations between some specific toxic compounds and lowered sperm counts, testicular cancer, and genital deformities. However, they found themselves again and again up against men whom Naomi Oreskes has elsewhere referred to as the “Merchants of Doubt”—displaced cold warriors, industry scientists, and public relations experts who parse data and insist on a certainty where they know none will exist. As Davis reminds us, “the absence of definitive evidence on specific exposures should not be confused with proof that no such harm exists.”

These problems and issues have become global. In part three, “The View from Outside,” Davis shows how exported air pollution and toxic exposures have started to be attended to in various national and international contexts. Yet Davis argues that there is so much more that still needs to be done. “For years, life, death, climate, and sex were all believed to be beyond our control. We now understand that each of these complex and exquisitely important aspects of life is subject to more human influences than have been imagined.” While examining air pollution, climate change, and the export of these harms, Davis makes a plea that we live up to our best abilities and once again put science back to work for people.

Through this very important, engaging, and well researched study, Devra Davis reminds us that environmental justice in our very complex and modified world demands that we fill the yawning and intentional gaps between scientific knowledge and environmental policy around toxic and hazardous substances.