Air pollutants from wood burning become more important as other regulated emissions are being reduced, e.g. combustion of diesel. We analysed particles in residential areas and found that local wood burning was the most important source of polycyclic aromatic hydrocarbons (PAHs). Specific tracers were used to separate wood combustion from other contributions. Calculations of population exposure showed that the mix of PAHs may cause 13 cancer cases per 0.1 million inhabitants.