Smog Kills

Breathing dirty air in America can kill you.

In a nutshell, that's the result of a new National Research Council report.

"Short-term (less than 24-hour) exposure to current levels of ozone in many areas is likely to contribute to premature deaths," the council reports, and at a rate that is higher than previously assumed. That means that the cost-benefit analysis the Environmental Protection Agency does when setting new air quality rules should favor heavier regulation to get more pollution out of the air.

Ozone is the main component of smog (it's beneficial in the stratosphere, but damages the lungs at ground level). It's primarily a summertime pollutant, and many Americans are familiar with ozone alerts on hot, sunny days. That's because tailpipe and smokestack pollution reacts in the hot sun to form ozone, which can penetrate deep into the lungs, causing scarring, coughing fits and other damage.

That damage makes certain people – those with pre-existing lung disease, for instance – susceptible to death by breathing dirty air, but it doesn't just claim the lives of those just a few days from death already, according to the new research. In other words, it won't cut you down in the prime of life, but it won't wait for the exit stage left cue either.

Here's how the NRC described portions of its results:

EPA, like other federal agencies, is required to carry out a cost-benefit analysis on mitigation actions that cost more than $100 million per year. EPA recently used the results of population studies to estimate the number of premature deaths that would be avoided by expected ozone reductions for different policy choices, and then assigned a monetary value to the avoided deaths by using the value of a statistical life (VSL).

The VSL is derived from studies of adults who indicate the "price" that they would be willing to pay – i.e. what benefits or conveniences someone would be willing to forgo – to change their risk of death in a given period by a small amount. The monetary value of the improved health outcome is based on the value the group places on receiving the health benefit; it is not the value selected by policymakers or experts.

EPA applies the VSL to all lives saved regardless of the age or health status. For instance, a person who is 80 years old in poor health is estimated to have the same VSL as a healthy 2-year-old. To determine if an approach that accounts for differences in remaining life expectancy could be supported scientifically, EPA asked the committee to examine the value of extending life. For example, EPA could calculate VSL to estimate the value of remaining life, so a 2-year-old would have a higher VSL than an 80-year-old. It is plausible that people with shorter remaining life expectancy would be willing to devote fewer resources to reducing their risk of premature death than those with longer remaining life expectancy. In contrast, if the condition causing the shortened life expectancy could be improved and an acceptable quality of life can be preserved or restored, people may put a high value on extending life, even if they have other health impairments or are quite elderly.

The committee concluded that EPA should not adjust the VSL because current evidence is not sufficient to determine how the value might change according to differences in remaining life expectancy and health status. However, the committee did not reject the idea that such adjustments may be appropriate in the future. To move toward determining a value of remaining life, alternative approaches should be explored in sensitivity analyses, and further research should be conducted to answer the questions raised about the validity of EPA's current approach.

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