| ObjectiveTo evaluate the effects of human activities and air purifier on concentrations ofairborne microorganisms and particles in a bronchoscopy room.MethodsThe present study was carried out in a 28m2 bronchoscopy room and was divided into two principal parts.The Part I included three groups:static group without human activities,dynamic group 1 with less human activities,dynamic group 2 with more human activities.Airborne microorganisms including bacteria and fungi were detected and cultured in all air samples collected with a single stage impactor sampler,and then species were identified.Particles were measured using a direct-reading airborne particle counter DT-9881M in five scheduled time points(Oh?0.5h?1h?2h?4h).The Part II included six groups:static no purification group(without human activities and without air purifier),static purification group(without human activities and with air purifier),dynamic no purification group 1(with less human activities and without air purifier),dynamic purification group 1(with less human activities and with air purifier),dynamic no purification group 2(with more human activities and without air purifier),dynamic purification group 2(with more human activities and with air purifier).Airborne microorganisms and particles were measured using the same methods as the Part I.Mixed model analysis was used to evaluate the effects of human activities and air purifier on concentrations of airborne microorganisms and particles.Results1.The concentrations of total airborne microorganisms(bacteria plus fungi),bacteria,fungi in static group were(149.33±4.98)CFU/m3,(84.33±3.65)CFU/m3,(65.00±2.66)CFU/m3,in dynamic group 1 were(203.20±10.92)CFU/m3,(113.53±7.78)CFU/m3?(89.67±7.17)CFU/m3,in dynamic group 2 were(299.85±13.92)CFU/m3,(186.29±13.04)CFU/m3.(113.56±6.45)CFU/m3.The concentrations of total airborne microorganisms,bacteria and fungi in dynamic group 1 were significantly higher than static group.The concentrations of total airborne microorganisms,bacteria and fungi in dynamic group 2 were significantly higher than static group and dynamic group 1(all p<0.05).2.The concentrations of PM2.5 and PM2.5-10.0 in static group were(45812.64±1279.61)counts/m3 and(189.15±4.64)counts/m3,in dynamic group 1 were(86557.20±4158.29)counts/m3 and(659.69±38.91)counts/m3,in dynamic group 2 were(53907.39±1226.79)counts/m3 and(403.04±10.98)counts/m3.The concentrations of PM2.5 and PM2.5-10.0 in dynamic group 1 were significantly higher than static group and dynamic group 2(all p<0.05).However,the concentrations of PM2.5 and PM2.5-10.0 in dynamic group 2 were significantly lower than dynamic group 1(p<0.05).3.In static group the concentration of airborne bacteria accounted for 55.3%of total microorganisms and airborne fungi accounted for 44.7%.Gram positive cocci were the most common bacteria(70%)and followed by negative bacilli(15%).Penicillium and aspergillus were the most common fungi.4.The concentrations of particles with various size in each group were PM0.3-0.5>PM0.5-1.0>PM1.0-2.5>PM2.5-5.0>PM5.0-10.0>PM?10.0,PM0.3-0.5?PM0.5-1.0 and PM1.0-2.5 was the three most common PM.That is to say,PM2.5 was the most common PM in selected bronchoscopy room,accounted for more than 99%of total particles.5.No matter whether human activities existed or not and what the numbers of activities were involved,BA-6065 could significantly decrease the concentrations of airborne bacteria,PM2.5 and PM2.5-10.0(all p<0.05).There was no significant difference in the concentration of total microorganism or fungi between purification group and no purification group(all p>0.05).ConclusionThe findings regarding the increased concentrations of bacterial and fungal bioaerosols and particles with human activities and the inhibitory effect of air purifier may be meaning for exploring control methods against hospital-acquired respiratory infection through bioaerosols. |
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