We studied the local response of the bronchoalveolar cell population after acute exposure to smoke from pyrolysis of Douglas fir wood. Cell viability experiments and function of the pulmonary macrophages were assessed, including adherence to surfaces, bacterial phagocytosis, and the intracellular bactericidal process. The smoke-exposed group (n=23) when compared with control animals (n=15) produced a significantly greater total cell yield (p less than 0.01) on bronchoalveolar lavage. There was no increase in the percentage of polymorphonuclear leukocytes. As carboxyhemoglobin levels increased, macrophage adherence to glass decreased (r = -0.79, p = 0.0001). Pulmonary macrophages from exposed animals were 33% less adherent at 120 min in vitro; however, these nonadherent smoke-exposed macrophages remained viable (55 to 78% viable by trypan blue dye exclusion). Both the phagocytic rate (361 14C cpm/unit time) and the maximal number of bacteria associated (at 60 min) with the exposed macrophages were significantly less than in the sham-exposed animals (uptake = 672 14C cpm/time, p less than 0.002 for each). The antibacterial properties of pulmonary macrophages are adversely affected by exposure to wood pyrolysis.