Biological monitoring of wood-smoke exposure

It has been clearly established that exposure to wood smoke is associated with a variety of adverse health effects in humans. However, we still have much to learn about the relationship between wood-smoke exposure and disease, including determination of what should be considered a "safe" level of exposure, and whether wood smoke should be regulated separately from other sources of air pollution. To help answer these questions, improved measures of exposure in populations exposed to wood smoke are required. In this mini-review we discuss how biomarkers of exposure can be used to complement the current suite of methods used to assess wood-smoke exposures. We critically review the compounds that are currently being evaluated as biomarkers of exposure to wood smoke, and we identify the strengths and weaknesses of these compounds. We find that, in general, these compounds show promise in situations where wood-smoke exposures are high, but where exposures are low non-wood-smoke sources are likely to be the major determinants of biomarker levels. We also outline a research framework that will move this field forward and maximize the potential for wood-smoke biomarkers to add value to epidemiological studies of wood-smoke health effects.