164 The aerosol emission characteristics and control strategies of flushing toilets

A poorly designed toilet can be a flaw in epidemic prevention. Previous studies have confirmed that humans are easily infected by related bioaerosols generated from toilets, and these droplet particles also have been proven to have the ability to carry out bacteria or viruses. In other words, whether in public places or homes or even in health care agencies and isolation wards, it has been a long-neglected source of airborne pathogen production. Three types of toilets were measured for aerosol emission characteristics, including the siphon toilet, washdown toilet, and siphon jet toilet. Two different commercial toilet cleaning products were added to the water tank to compare the effects on particle emissions under different surface tension. Then, the impact of different flushing conditions and the effectiveness of commercial toilet lids in preventing the escape of particles were compared. Under the standard flush situation (6 L) the total count of particles was 5.5x105 #, the CMD was 0.2 μm and the GSD was about 1.8. Flush volume is positively correlated with the total particle count. However, other factors must also be considered between different types of toilets. The toilet cleaning products, while helping to clean the toilet surface, may lead to generate more particles. Then, the toilet lids can effectively reduce particle escape, but there is still a need for improvement in preventing particle escape. Based on the existing data, these results will provide the basic techniques to reduce droplet particle generation. And it can be concluded that there is still a need for improvement in current toilets, particularly in epidemic prevention.