Wildfires lead to costly health problems

Wildfire air pollution worsens respiratory and cardiac
health issues for people far away, scientists warn.

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.

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.

Source: The Guardian

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Demanding physical work associated with an increased risk of cardiovascular disease

Two studies presented at this year's EuroPRevent 2013 congress suggest that demanding physical work has a detrimental effect on an individual's risk of coronary heart disease.

The first was a case-control study described by Dr Demosthenes Panagiotakos, Associate Professor of Biostatistics-Epidemiology at Harokopio University, Athens, which evaluated occupation in 250 consecutive patients with a first stroke, 250 with a first acute coronary event and 500 equally matched controls.(1) Overall, when assessed on a 9-unit scale (1 = physically demanding work and 9 = sedentary/mental work) the analysis showed that those suffering the stroke and coronary events were more commonly engaged in physically demanding occupation than the controls.

After adjusting for various potential confounding factors such as age, sex, body mass index, smoking, hypertension, hypercholesterolemia, diabetes, family history of cardiovascular disease and adherence to the Mediterranean diet, results confirmed that those occupied in progressively less physically demanding jobs (that is, for each unit increase of the scale) were associated with a 20% lower likelihood of acute coronary events (a statistically significant odds ratio of 0.81%) or of ischaemic stroke (odds ratio 0.83%).

Commenting on the results, Dr Panagiotakos said that subjects with physically demanding manual jobs should be considered a primary target group for prevention of cardiovascular disease because of their higher risk.

Within the context of exercise recommendations, he noted that the somewhat paradoxical results could possibly be attributed to the stress experienced by people with physically demanding jobs. Stress, he added, may be one reason why hard physical work may not be comparable to the physical exercise recommended for health and well-being, which tend to be non-stressful behaviours. In addition, he explained, such work is often not well paid, which may restrict access to the healthcare system.

A second study reported here from investigators in Belgium and Denmark also supports the view that physically demanding work is a risk factor for coronary heart disease, even when leisure-time activity is taken into account.(2)

This was a cohort study of more than 14,000 middle-aged men who were free of coronary disease at the outset of the study in 1994-1998. Standardised questionnaires were used to assess socio-demographic factors, job strain and the level of physical activity at work and during leisure time. Classical coronary risk factors were also measured through clinical examinations and questionnaires.

The incidence of coronary events was monitored during a mean follow-up time of 3.15 years, with statistical modelling applied to assess the association between physical activity and coronary disease. Again, adjustments were made for age, education, occupational class, job strain, body mass index, smoking, alcohol consumption, diabetes, blood pressure, and cholesterol.

Results during follow-up showed an overall beneficial effect of leisure time physical activity, but an adverse effect of demanding physical work. However, Dr Els Clays, from the Department of Public Health at the University of Ghent, Belgium, added that an "interaction effect" was also evident in the results: while moderate-to-high physical activity during leisure time was associated with a 60% reduced risk of coronary events in men with low occupational physical activity (a statistically significant hazard rate of 0.40), this protective effect was not observed in those workers who were also exposed to high physical work demands (HR 1.67).

Dr Clays added that, after adjusting for socio-demographic and well established coronary risk factors, men with high physical job demands were more than four times likely to have coronary heart disease when they also engaged in physical activity during leisure time (HR 4.77).

Commenting on the results Dr Clays said: "From a public health perspective it is very important to know whether people with physically demanding jobs should be advised to engage in leisure time activity. The results of this study suggest that additional physical activity during leisure time in those who are already physically exhausted from their daily occupation does not induce a 'training' effect but rather an overloading effect on the cardiovascular system. However, only few studies until now have specifically addressed this interaction among both types of physical activity, and conflicting findings have been reported. More research using detailed and objective measures of activity is needed."