Aerosols and Bacteria From Hand Washing and Drying in Indoor Air

Abstract

Effective hand drying is an important part of hand hygiene that can reduce the risk of infectious disease transmission through cross-contamination of surfaces by wet hands. However, hand drying methods may also cause aerosolisation of pathogenic microorganisms if they are present in washed hands. This study investigated experimentally the impact of washing hands and different hand drying methods on the concentration and size distribution of aerosols and bacteria in indoor air. In this experiment, aerosol and bacteria concentrations were measured in indoor air while volunteers rinsed their hands with water or washed with soap and water prior to drying them with paper towels or jet air dryers. Results showed that the concentration of aerosols and bacteria in air increased with people walking in the room and washing hands, with a further increase during the hand drying process. The concentration of aerosols decreased with particle size, with maximum concentrations after drying hands of 6.63 × 106 ± 6.49 × 105 and 2.28 × 104 ± 9.72 × 103 particles m−3 for sizes 0.3 to <0.5 and ≥5.0 μm, respectively. The concentration of bacteria in indoor air after drying hands increased to a maximum of 3.81 × 102 ± 1.48 × 102 CFU m−3 (jet air dryers) and 4.50 × 102 ± 4.35 × 101 CFU m−3 (paper towels). This study indicates that the increase of aerosols and bacteria in air after drying hands with jet air dryers or paper towels are comparable and not statistically different from concentrations associated with walking and washing hands in the same environment. This work can support the development of hand hygiene practices and guidelines for public washrooms.

Handwashing Practice of Food Establishment Customers, Microbial Quality of Handwashing Water, and Associated Factors in Ginjo Kebele, Jimma Town, Southwest Ethiopia

“…Consequently, the water quality in turn affected the hand hygiene status of customers together with the other factors as described in Table 7. This finding is supported by the other's work as the source of water, 18 handwashing facility conditions (unavailability of soap 42 ), and customers' improper handwashing practice, 31,43 inadequate handwashing time, lack of training 5,24,44 and unavailability of poster demonstration on good handwashing practice, inappropriate method of hand drying 34,45,46 and method of fetching water from the container 32 had an association with the effectiveness of handwashing practice in the removal of pathogens from hands thereby hand hygiene status.…”

Science behind children’s handwashing: action study of 9- to 10-years-old elementary school students in Japan

“…Most previous studies on handwashing have been conducted among health professionals and students, primarily focusing on knowledge ( 19 , 20 ). Although there have been reports ( 21 ) on food hygiene among university students, to our knowledge, hand hygiene education utilizing objective indicators such as the ATP test has not been implemented in elementary schools.…”

Indoor particle dispersion due to hand dryer in public washroom: an in silico study

“…Effective hand drying reduces cross-contamination compared to dry hand by touching surfaces [11][12][13] . However, the hand dryer itself can be a source of contamination and disperses microorganism through aerosol particles 14,15 .Substantial articles have investigated the hygienic effects of hand dryers. Suen et al 8 indicated that drugresistant bacteria could be found in 52 types of bacteria species on hand-drying facilities in public washrooms, and Huesca et al 9 demonstrated that hand dryers were related to the bacterial deposition on hand surfaces and the movement of polluted air, and might even be a cause for the dispersion of infectious bacteria.…”

“…Effective hand drying reduces cross-contamination compared to dry hand by touching surfaces [11][12][13] . However, the hand dryer itself can be a source of contamination and disperses microorganism through aerosol particles 14,15 .…”