Objective: To compare nasal mucociliary clearance (NMC) functions in coal workers with pneumoconiosis, coal workers without pneumoconiosis and healthy controls by using technetium-99m-labeled macroaggregated albumin rhinoscintigraphy. Methods: Sixty-five of the 86 coal workers were clinically documented as suffering from coal workers' pneumoconiosis (CWP group). CWP workers were divided into two groups according to smoking status: 44 smokers (CWP-S) and 21 nonsmokers (CWP-NS). Twenty-one workers without pneumoconiosis (NCWP group) were similarly divided into two groups: 12 smokers (NCWP-S) and 9 nonsmokers (NCWP-NS). Thirty-three healthy male volunteers were selected for the control group [ 15 smokers (control-S), 18 nonsmokers (control-NS)]. The half-time (t(1/2)) value for the clearance of the radiopharmaceutical was calculated for each patient. Results: Mean t(1/2) values for CWP-S, CWP-NS, NCWP-S, NCWP-NS, control-S and control-NS were 25.10 +/- 7.75, 10.97 +/- 3.24, 14.68 +/- 4.98, 9.17 +/- 3.71, 19.15 +/- 5.04 and 15.08 +/- 5.11, respectively ( p < 0.001, Kruskal-Wallis variance analysis). Further, mean t(1/2) values of smokers versus nonsmokers in CWP, NCWP and control groups were compared, and it was found that although smoking prolonged nasal transport time in all three groups, the difference was significant only in the CWP group ( p < 0.001, p < 0.023 and p < 0.027, respectively, Bonferroni-adjusted Mann-Whitney test). Conclusion: Our findings demonstrated a synergistic detrimental effect of smoking with coal dust exposure on nasal transport time. Copyright (C) 2005 S. Karger AG, Basel.