Abstract
Environmental effects such as dust mitigation can amplify the spread of viruses via inhaling infected dust particles. Infusion and the spreading rate of human saliva over the dust particles can play a critical role in contiguous virus spread. In the present study, mechanical and chemical interactions of human saliva with environmental dust particles are considered. The saliva droplet impact on dust particles is examined while mimicking saliva droplet spreading during coughing in a dusty ambience. The mechanisms of saliva infusion and cloaking on the dust particles are explored. The characteristics of saliva droplet normal and oblique impacts on a dust particle are examined experimentally and numerically to evaluate the amount of saliva residues on the impacted particle surface. The findings reveal that the saliva liquid infuses and cloaks the dust particle surfaces. The saliva droplet impact on the dust particles leaves a considerable amount of saliva residues on the impacted surfaces, which remain undried for a prolonged period in indoor environments. Weak adhesion of the saliva-infected dust particles on surfaces, such as glass surfaces, enables saliva-infected dust particles to rejoin neighboring ambient air while possessing a high potential for virus spreading.