Secondary exposure and risk assessment of biocides as disinfectant sprays for COVID-19 prevention

The importance of disinfection has recently increased owing to the spread of infections, such as coronavirus disease 2019 (COVID-19). However, exposure to the biocidal products used for disinfection poses health risks. This study aimed to determine the safe use of biocides and the potential for secondary exposure in the general population. To obtain information on the exposure factors on site, an interview survey was conducted for 2 weeks and 10 days using a questionnaire. Toxicology studies were performed to determine the toxicity of each chemical in various biocidal products. The inhalation and dermal exposure algorithms in ConsExpo 4.0, a software developed by the Dutch National Institute for Public Health and the Environment (RIVM), were used to assess the risk of active substances in biocidal products. The average amounts of disinfectants and pesticides used in indoor environments per unit time were 5948.50 ± 72,434.76 mg and 201.61 ± 305.91 mg, respectively. Ethanol had the highest inhalation hazard quotient (HQ_inh) of 1.48E+02 while sodium dichloroisocyanurate had the lowest value of 1.74E-10. The HQ_inh/HQ_der ratios for the 10 active substances ranged from 1.51E+00 to 2.73E+05 were greater than 1, indicating that inhalation exposure had a greater effect than dermal exposure. The hazard index (HI) of the 10 active substances, excluding ethanol, was less than 1, indicating the absence of potential health risks. Therefore, to reduce the health risks associated with secondary exposure, disinfection should be performed during periods when individuals are away from the site to be disinfected, such as after regular working hours, and individuals should be encouraged to enter this site the following day instead of after the disinfection exercise. Methods, such as applying an active substance from a biocidal product to a cloth or fabric to carry out the disinfection protocol, should also be considered.