Title: Sensitivity of airborne transmission of enveloped viruses to seasonal variation in indoor relative humidity Show Chinese title

Title: 包膜病毒空气传播对室内相对湿度季节性变化的敏感性

Abstract: In temperate climates, infection rates of enveloped viruses peak during the winter. While these seasonal trends are established in influenza and human coronaviruses, the mechanisms driving the variation remain poorly understood and thus difficult to extend to similar viruses like SARS-CoV-2. In this study, we use the Quadrature-based model of Respiratory Aerosol and Droplets (QuaRAD) to explore the sensitivity of airborne transmission to the seasonal variation in indoor relative humidity across the wide range of relevant conditions, using SARS-CoV-2 as an example. Relative humidity impacts the evaporation rate and equilibrium size of airborne particles, which in turn may impact particle removal rates and virion viability. Across a large ensemble of scenarios, we found that the dry indoor conditions typical of the winter season lead to slower inactivation than in the more humid summer season; in poorly ventilated spaces, this reduction in inactivation rates increases the concentration of active virions, but this effect was important when the susceptible person was farther than 2 m downwind of the infectious person. On the other hand, changes in particle settling velocity with relative humidity did not significantly affect the removal or travel distance of virus-laden scenarios. Show Chinese abstract

Abstract: 在温带气候中，包膜病毒的感染率在冬季达到峰值。 虽然这些季节性趋势在流感病毒和人类冠状病毒中已被确立，但驱动变化的机制仍不明确，因此难以推广到类似病毒如SARS-CoV-2。 在本研究中，我们使用呼吸气溶胶和液滴的二次方模型（QuaRAD）来探讨空气传播对室内相对湿度季节性变化的敏感性，以SARS-CoV-2为例。 相对湿度影响空气颗粒的蒸发速率和平衡大小，这可能进一步影响颗粒去除速率和病毒粒子的存活能力。 在大量情景的集合中，我们发现冬季典型的干燥室内条件比夏季更潮湿的条件导致失活速度较慢；在通风不良的空间中，这种失活速率的降低会增加活性病毒粒子的浓度，但当易感人员位于感染人员下风方向超过2米时，这种影响才显著。 另一方面，相对湿度变化对颗粒沉降速度的影响并未显著影响病毒载荷情景的去除或传播距离。