超声波加湿室内微生物气溶胶浓度与优化方法

为明确超声波加湿对冬季供暖室内微生物气溶胶粒径与浓度分布的影响,以及降低暴露风险的有效方法,针对典型办公室环境,基于模拟实验法与正交试验法,探究不同相对湿度(RH=40%、55%、70%)、加湿器水质(蒸馏水、自来水、凉白开)和窗户开度(0、1/6、1/3)下,超声波加湿前后室内细菌、真菌气溶胶按粒径分级的浓度变化,并结合极差分析与层次分析法(AHP)对上述因素的影响权重排序.结果表明,超声波加湿后,细菌、真菌气溶胶的浓度增长率分别高达294%和798%,且分布(0.6~4.7µm)集中在人员可吸入范围.影响加湿室内微生物暴露量的因素权重排序为:水质(45%)>目标湿度(44%)>窗户开度(11%).为最大限度降低暴露风险,建议用户使用超声波加湿器时,优先选用蒸馏水,调节目标湿度至中等水平.

Impacts of ultrasonic humification on size-distribution and concentration variations of indoor bioaerosol and its optimization strategy

This work experimentally investigated the size-distribution and concentration changes of indoor bioaerosol before and after ultrasonic humidification via the orthogonal experiment methods in three heated experimental chambers (23℃) to clarify the exposure risk of indoor airborne bacteria and fungi during ultrasonic humidification. Effectiveness of three well-recognized influencing factors, i.e., target relative humidity (RH=40%, 55%, 70%), humidifier water type (distilled water, tap water, cooled boiled water), and window opening degree (0, 1/6, 1/3) on mitigating the exposure risks was also rated according to Range Analysis and Analytical Hierarchy Process (AHP). The results showed a substantial increase of indoor bacterial and fungal aerosol concentrations, by 294% and 798%, respectively, after ultrasonic humidification; the surged microbes were concentrated in the inhalable ranges. The three factors varied in their effectiveness in mitigating the bioaerosol exposure during humidification, which was ranked by AHP as: humidifier water quality (45%)> target relative humidity (44%)>window opening (11%). To minimize the exposure risks, distilled water and a medium humidification level (such as RH=55%) should be prioritized for ultrasonic humidification, while the effect of window opening degrees is relatively insensitive.