RESUMEN
Objective To explore the effects of two air sampling methods including natural precipitation method and impacting method for detecting the bacterial count of indoor air of workplace of cosmetic plants. Methods The diameters of 44 glass bacteria-culture plates for those two sampling methods were measured. The indoor air of workplace of cosmetic plants were sampled by those two sampling methods simultaneously. The natural precipitation method was performed for 5- minute exposure ,the impacting method was performed by MAS-100 airborned bacteria sampler at flow rate of 100 L/min for 30 s,2 min,8 min respectively.All of the data on the bacterial counts of air obtained from various sampling ways were statistically analyzed.The measures for quality control of air sampling progress were put forward also. Results The diameters of 44 glass bacteria-culture plates were 8.39-8.70 cm,which were lower than the standard(9 cm?雪. The bacterial counts of air samples collected by natural precipitation method at the same location showed higher coefficient of variation,higher median,lower qualified rate compared with those by impacting method. The bacterial counts of air decreased,when the impacting sampling method was performed for 8 min continuously with sampling volume of 800 L. Conclusion The impacting method with advantages including mere influence from external environment and better precision could be primarily applied for air sampling in general condition,but it might show lower efficiency of collecting the airborne bacteria during the longer sampling period with higher sampling volume. The natural precipitation method with poor precision was suitable for longer term (8-30 min)air sampling in the relatively static environment with lower air flow and highly cleaned air. The bacterial counts of air obtained from natural precipitation method should be corrected if the diameters of glass bacteria-culture plates weren't meet the requirement of the national standard (9 cm?雪.