A compact compound annular denuder, with a removal efficiency for volatile polynuclear aromatic hydrocarbons (PAH) of at least 90% at flow rates of up to 200 L/min, was designed for use with the PS-1 sampler. Laboratory tests of this denuder showed no detectable (< 10%) removal of ambient particulate matter larger than 0.1 micrometer mean diameter at flow rates of 100-200 L/min. The vapor collection efficiency, as measured with naphthalene, was better than 95%, and the capacity for removal of approximately 180 micrograms of naphthalene was better than 90%. The field experiments consisted of three series: (1) outdoors during the winter; (2) indoors within a laboratory; and (3) outdoors during the summer. In these experiments a denuder difference approach was followed to monitor the phase distributions of 18 PAH. The results in general are consistent with previous work and extend the overall body of information on the phase distributions of PAH and their tendencies for artifact formation as a result of volatilization during sampling. Phase distributions for PAH were shown to be well represented by the Dubrinin-Radushkevich isotherm under both summer and winter conditions.