Wildfires: Where There's Smoke There's Illness
Trying to get a handle on how best to fight wildfires should include understanding the fires' collateral damage.
Where there’s smoke there’s fire runs the old saw, but the reverse is usually equally true: Where there’s fire there’s smoke. And where there’s wildfires, there’s lots of smoke, especially as fires become bigger and more destructive (although not automatically more common). Surely it's a bad idea to be breathing that hazy residue.
A new study looking a four years worth of wildfires upwind from Reno, Nevada, puts some numbers on that common-sense observation and suggests that ill effects of wildfire smoke may be present as much as 300 miles from the burning. Researchers led by resource economist Klaus Moeltner of Virginia Tech compared the toll of acres burned to data on air pollution and hospital admissions for respiratory and cardiovascular problems.
Keeping in mind that the average fire they studied was 50,200 acres—the size of Madison, Wisconsin—they report:
Accounting for lagged effects, we find that an additional 100 acres burned cause between $60 and $210 in inpatient treatment costs for acute respiratory problems, depending on fire distance and primary fuel type. The analogous cost estimates for cardiovascular admissions range from $70 to $260. For the 2008 fire season this translates into total smoke-induced inpatient costs in Reno/Sparks of close to $2.2 million.
If those figures seem bearable in the scheme of things, keep in mind that these costs are limited to a metro area of about 350,000 people (granted it is the "the biggest little city in the world") and to heart and lung issues. It doesn’t look at the cost of cowering indoors afraid to venture outside, or the costs of visits to the emergency room, family doctor, or outpatient clinic. The authors themselves see their numbers as the “lower bounds” of a wildfire’s mixed economic toll:
Beyond medical expenses, our cost estimates are likely just the tip of a much larger iceberg of total economic losses from wildfire smoke in downwind communities. Additional costs would include non-market components such as decreased productivity and forgone recreational opportunities.
The urban area of Reno offered Moeltner’s team “an ongoing natural experiment” for studying these issues thanks to the general dryness of the Great Basin location, prevailing winds that blow smoke into town, a large number of wildfires within 500 miles that vary in size from 700 acres to 190,000, and various habitats—grasses, sage/juniper stands, full-blown forests—that burn. Their study period ranged from March 2003 to December 2008; 2008 was a particularly “intense” fire year for the region.
What made their study different from the pack—and there are a number of wildfire/health surveys drawn from fire-prone study sites in North America, South Africa, and Australia—is that these researchers looked at the day-to-day figures over 1,399 days, which gave them lots of fires to examine.
The researchers looked most at health issues that could be related to breathing in particles 2.5 microns or larger, a traditional yardstick for looking at pollution. At that size the particles cause both haze and health concerns. The researchers also looked at wildfire pollutants carbon monoxide and ozone, which, while definitely bad for you, usually don’t lead directly to the hospital. Most of what we do know about the effects of smoke on health, by the way, comes from studying cooking fires using wood as a fuel and from industrial sources in big cities (not to mention studies on smoking).
A 2006 study found that about a third of the particulate matter in Canada’s air came from forest fires, and the cost of dealing with the medical implications of that was rivaled only by the cost of lost timber itself. “However,” that paper reads, “air quality concerns are not typically included in resource allocation decisions in fire management.” Just ask the residents of Kuala Lumpur….
That’s one of the reasons this new study matters. "The design of efficient wildfire programs requires an understanding of the ‘values at risk’ or—alternatively put—the expected benefits from preventing or suppressing a fire event,” the authors write.
For example, preemptive fuel reduction efforts may be more cost-effective in an area that is upwind from a large population zone, ceteris paribus. The same rationale holds for the allocation of combative resources after a fire has started. Furthermore, reducing wildfire smoke via such interventions may produce net gains even at a large distance from the impact area.
In other words, even where there isn’t a nearby fire, there may be smoke.