Blowing in the wind: Bacteria and fungi are spreading from public restroom hand dryers

Copper oxide particle emission and the spread in a public washroom from a high-speed jet air dryer

The high-speed jet discharged by hand dryers with brushed motors may release hazardous particles. In this study, the particles released from the hand dryer were trapped using high-efficiency particulate air filters for chemical composition analysis in a small test room. A manikin was placed to mimic a user standing in front of the dryer. Number and mass concentrations of the released particles were measured to estimate the particle emission rates and inhalation exposure. The particle emission rate reached 2.64 × 106 particles/s when starting the dryer. The released particles were found to contain a copper element, subsequently extrapolated to copper oxide. Secondly, in the large test room, jet airflows were measured using a three-dimensional ultrasonic anemometer. The results revealed that the horizontally placed palms caused the discharged jets to bend toward the human body, resulting in an upward motion of the air into the breathing zone. After running the dryer for 30 s, the peak mass concentration in the breathing zone for particles with a less than 2.5-μm diameter was 13.1 µg/m3. Installing high-efficiency particulate air filters to the air outlets of hand dryers was found to be effective in minimizing the exposure to CuO.

Effect of Optimal Alcohol-Based Hand Rub among Nurse Students Compared with Everyday Practice among Random Adults; Can Water-Based Hand Rub Combined with a Hand Dryer Machine Be an Alternative to Remove E. coli Contamination from Hands?

Efficient hand hygiene is essential for preventing the transmission of microorganisms. Alcohol-based hand rub (ABHR) is a recommended method. We compared health personnel (skilled nurse students) with random adults to study the effect of an ABHR procedure. A water-based hand rub (WBHR) procedure, using running tap water and a hand-drying machine, was also investigated. The study included 27 nurse students and 26 random adults. Hands were contaminated with Escherichia coli, and concentrations of colony forming units (CFU/mL) were determined before and after ABHR or WBHR. Concentrations after ABHR were 1537 CFU/mL (nurse students) and 13,508 CFU/mL (random adults) (p < 0.001). One-third of participants reported skin irritation from daily ABHR. Concentrations after WBHR were 41 CFU/mL (nurse students) and 115 CFU/mL (random adults) (p < 0.011). The majority of participants (88.5%) preferred the WBHR method. Results from 50 air samples from filtered air from the hand dryer outlet showed no CFU in 47 samples. A significant difference between the two groups was shown for the ABHR method, indicating that training skills are important for efficient hand hygiene. Surprisingly, the WBHR method seemed to have a significant effect in largely removing transient bacteria from hands.

Assessment of the effect of hand dryers used in shopping malls on hand hygiene

BACKGROUND

Hand drying is one of the most important factors affect hand hygiene. This study was conducted to investigate the effect of hand dryers used in the restrooms located on the food court floors in shopping malls in Turkey on hand hygiene.

METHODS

Hands were washed for at least 20 seconds by following hygienic hand washing procedures of the World Health Organization. Swab samples were taken from the wet hands after hand washing, then from the dry hands, which were dried under the hand dryers and from the air blowing part of the hand dryers. Samples were cultured on agar plates that were directly exposed to the air-blowing part of the hand dryers.

RESULTS

It was found that total coliform bacteria were 0.000 colony-forming unit (CFU)/petri in wet and dried hand, 3.437 CFU/petri in blown air and 5.250 CFU/petri in swab samples. Staphylococcus aureus was found to be 0.125, 64.125, 26.375, and 388.750 CFU/petri, respectively. Total bacteria count was found to be 0.687, 48.750, 35.625, and 595.000 CFU/petri, respectively. S. aureus and the total bacterial load were higher in the blower outlet of the hand dryers than washed hand, blown air and dried hand (P < .05). The bacteria count in the unfiltered hand dryers was higher than that in the filtered hand dryers (P < .05).

CONCLUSIONS

Using hand dryers would negatively affect hand hygiene even if hands were washed following hygienic hand washing procedures.