There are plenty of immediate concerns in a fire: protecting homes and businesses, saving lives, limiting the number of acres consumed and so on. But increasingly, researchers and policymakers are finding that the lingering health and safety impacts of wildfires may be far more worrisome – and more widespread.

Smoke, after all, can travel any way the wind takes it, exacerbating an array of health problems in cities hundreds of miles from the original fire. In 2002, for example, a fire in Canada caused a 30-fold increase in fine particulate matter in the air in Baltimore, 1,000 miles away.

According to Kim Knowlton, a senior scientist with the health and environment program at the Natural Resources Defense Council (NRDC), that level of air pollution can contribute to a variety of respiratory and cardiac issues and has even been correlated with premature death and low birth weights. In a 2011 study, conducted in partnership with researchers at the University of California at Berkeley and the University of California at San Francisco, Knowlton found that more than 760,000 encounters with the health system between 2000 and 2009 could be attributed to exposure to wildfire smoke.

These health problems carried a steep price tag: $740,000 in direct healthcare costs and more than $14bn in overall health costs once the value of lives lost prematurely was factored in. The 2003 wildfire season in southern California alone resulted in 69 premature deaths, 778 hospitalizations, 1,431 emergency room visits, and 47,605 outpatient visits, mostly for respiratory and cardiovascular health problems aggravated by smoke exposure.

A brewing health crisis

Scientists fear that, as climate change intensifies, the conditions that make wildfires likely – namely heat, drought, and shifting weather patterns – are becoming increasingly common, laying the foundation for more wildfires and a major public health crisis. In fact, there is evidence to suggest that we may already be in the midst of one: a 2011 brief from the NRDC found that two-thirds of US citizens live in counties affected by smoke conditions.

“It’s really bad stuff,” Knowlton says. “It’s not just the particulate matter in the smoke, but also that it carries ozone precursors, contributes to the formation of ground-level smog, and can contain carcinogens, ammonia, organic acids and metals.”

In its most recent report, the National Climate Assessment addressed the potential costs and risks of wildfire-related health concerns, noting that smoke from a fire could contribute to health impacts in regions far from the original disaster. Moreover, the report argued, particulate matter from wildfire-related smoke could affect atmospheric properties and thus weather patterns.

The National Institute of Environmental Health Sciences, NIEHS, has also addressed this side of the wildfire issue. For the past five years, it has taken a particular interest in research that examines climate change-related health impacts on vulnerable populations, and in 2010 launched dedicated funding for this research. The first of those grants began in 2011, including a project at Yale that aims to pinpoint which populations are most vulnerable to the health impacts of forest fires under a changing climate.

Still more research attempts to quantify the financial impact of wildfires. The 2008 fire season led to almost $2.2m in hospital costs in the Reno-Sparks area of Nevada, while the 78,000 wildfires in California between 1999 and 2013 burned approximately 3.8m acres and incurred more than $4bn in suppression costs, a recent Union of Concerned Scientists study reports.

And these impacts are likely to increase. In a Harvard University study on the effects of wildfires on US air quality, researcher Xu Yue estimates that by the middle of this century wildfires will have increased the amount of fine particulate matter in the air from 46% to 70%, and the amount of black carbon from 20% to 27%, relative to today’s numbers.

Not only are respiratory and cardiac issues expected to rise, but also, in a seemingly endless and vicious loop, the particulate matter and other chemicals contained in wildfire-smoke will further exacerbate climate change. A 2010 study from the National Center for Atmospheric Research and the University of Colorado at Boulder estimates that wildfires in the contiguous US and Alaska release about 290m metric tons of CO2 a year, which is the equivalent of 4%-6% of the nation’s CO2 emissions from burning fossil fuels.

Learning to live with fire

The Clean Air Act has gone a long way toward reducing the amount of particulate matter and other pollutants emitted into the air by companies. However, the act doesn’t cover air pollution caused by wildfires, and the combination of climate change and continued development in fire-prone areas could negate much of the improvement that it has brought about.

In a recent research brief, the Nasa Air Quality Applied Sciences Team alluded to this problem. It began by pointing out that US air quality has vastly improved in recent years: “Eight-hour averages of surface ozone (O3) have declined by nearly 20% since 1990, while 24-hour averages of fine particulate matter (PM2.5) have dropped by 25%.”

The report then noted, however, that these improvements are vulnerable to atmospheric disturbances: “Unusual weather can interrupt that trend, as was seen in the hot dry summer of 2012, when Chicago and St Louis experienced double the average number of O3 episodes from the previous four years.”

Given the difficulty of regulating fire-related air pollution, state and local agencies have focused instead on better communicating health risks to the public, creating early-warning systems, and integrating wildfire risks into climate adaptation plans. That means looking at everything from land-use management and development permits to forest management in an effort to minimize the impacts of wildfires in the future.

Even shifting the time of year that fire departments conduct controlled burns could have an impact; recent research has shown that extreme heat exacerbates the health impacts of fires, and thus recommends that controlled burns happen in the spring.

“There’s always a confluence of factors that contribute to any wildfire,” Rachel Cleetus, senior climate economist with the Union of Concerned Scientists, explains. “There’s development, whatever creates the initial spark, and past fire-suppression practices that have led to this accumulation of biomass that’s just a tinder box. Climate is adding an additional layer of risk, and that risk is only increasing.”

Helping people to understand the connection between climate change, wildfires, and their own health might help to address the problem as well.

“When climate change impacts are described as being on humans and family members and in the here and now and in your neighborhood as opposed to in forests in Colorado or polar bears in the Arctic, people tend to respond more and show more concern about the issue,” says John Balbus, senior public health advisor at NIEHS.

But of course, climate is not the only issue, nor is it the only area in which the general public has an impact on wildfire risk. As Cleetus says:

Cutting emissions is critical, but it won’t help people right now – we’re already locked in to temperature change for the next couple decades. We do need to cut emissions so it doesn’t get worse, but what can we do in the short term? We can invest in fire-proofing measures. We can limit further development in wildfire-prone areas and manage our forests better. In a way it’s learning to live with fire a little bit because that’s where we are. That’s a part of our national policy conversation that’s very difficult.

Amy Westervelt is an Oakland, California-based freelance reporter who covers the environment, business and health.

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