Motoya Hayashi

If we collect aerosols containing SARS-CoV-2 with condensed water and obtain the solution, a sensing device can detect the viruses, and we can easily take prompt countermeasures. First, we predicted a condensation mass flow rate on a cooling surface. Next, we sprayed saltwater in a chamber and collected the aerosols using a collector equipped with a cooling unit and a fan. We defined Δt′ based on the difference between the dew point and cooling surface temperatures. The collected liquid mass had a linear relation with Δt′. There were slight differences related to the airflow rate. For evaluating the collection efficiency, ηc was determined as the ratio of the salt concentration of the collected liquid to that of the sprayed. As the liquid mass reduced, ηc increased. When the airflow rate increased by 40 m3/h, ηc increased from 10% to 28%. The airflow rates did not affect the one-pass collection efficiencies much. We also confirmed that the condensation prediction was accurate. When the airflow rate was 140 m3/h, the coefficient of determination was 0.97, and the maximum residual error was −0.85 mg/s. Based on the prediction, the concentration of test substances can increase by controlling the cooling capacity.