Does Reactivating a Mint-Scented Mask Make It More Comfortable?

A mint-scented mask may make nasal discomfort feel less intense immediately after it is put on. But if the scent is repeatedly released again, does comfort improve each time? A 2020 study found an initial benefit from a scented mask, but no confirmed further reduction in discomfort after its scent was reactivated.

The researchers examined changes over six hours of everyday use and the added effect of reactivating the scent. Rather than comparing scented and unscented conditions just once, they repeatedly asked the same participants how their noses felt.

Forty people used scented and unscented masks on different days

Participants were 40 women aged 34–57 with hay fever. On two days in April 2019, each wore a scented mask and an unscented mask for six hours each. Half were randomly assigned to use the scented mask first; the other half used the reverse order.

The masks shared the same basic materials and shape. The scented version contained a fragrance made with L-menthol and Japanese mint oil. Its scent was released by lightly tapping the nonwoven fabric.

At 10 a.m., participants rated nasal discomfort on a five-point scale immediately before and after putting on the mask. They then responded to emails sent to their mobile devices at 10:30 a.m., 11 a.m., noon, 2 p.m., and 4 p.m. In the scented condition, after providing the current rating, they were also asked to tap the mask to reactivate its scent, put it back on, and rate discomfort again.

Because responses were collected during everyday life, some data were missing. Analyses used 21 participants for the complete time series, 35 for the immediate before-and-after comparison, 22 for the time series from 10:30 a.m. onward, and 30 for the comparison before and after scent reactivation. Not every finding came from complete records for all 40 participants.

The mint-scented mask felt more comfortable immediately after application

Before application, nasal sensations did not differ between the conditions. Discomfort decreased after putting on either mask, but the reduction was greater in the scented condition, whose immediate ratings were significantly more comfortable than those for the unscented condition.

For both masks, the main changes occurred within about 30 minutes of application. After that, comfort did not continue improving with time. The authors describe this as saturation of the effect.

Importantly, the findings did not show that the benefit of the scent disappeared after 30 minutes. The analysis across 10:30 a.m. to 4 p.m. still found a significant difference between scented and unscented masks. However, neither a change in that difference over time nor additional improvement with time was clear.

Reactivating the scent did not clearly add further improvement

The researchers initially expected discomfort to decrease each time the scent was reactivated. However, comparisons before and after reactivation at each time point did not show a statistically significant effect.

The finding indicates that comfort when first encountering the scent and changes after renewing the stimulus did not emerge in the same way. The authors interpret the results as suggesting that, once comfort was established, its level was maintained during wear and did not increase further with reactivation.

However, scent intensity itself was not measured at each time point. The data alone cannot determine whether the result reflected adaptation to the odor, a lasting first impression, or limited room for further improvement on the comfort scale.

A difference in willingness to engage with work or housework

After six hours, participants also answered six questions covering wearing comfort, fit to the face, size, ease of breathing, freedom from ear pain, and willingness to engage with work or housework.

The only significant difference concerned feeling positive about tackling work or housework, for which the scented mask received more favorable ratings. The other aspects of wearing experience did not differ clearly.

This was a report of participants’ feelings, not a measurement of work performance or how much housework they completed. The researchers also noted that greater perceived nasal comfort did not translate into uniformly better ratings of every aspect of mask use.

The study measured nasal discomfort, not airflow or inflammation

A strength of the study was that it followed changes over time while people actually wore the masks for an extended period in daily life. However, sensors or similar measures were not used to confirm that instructions on wearing the masks and reactivating the scent were always followed.

The study also did not measure nasal airflow, inflammation of the nasal lining, or allergic responses to pollen. There was no condition separating nasal sensations from menthol and related substances from mood or expectations elicited by the scent. The authors identify distinguishing direct sensory effects from effects mediated by mood as a subject for future work.

The findings therefore concern how nasal discomfort was perceived by these participants under these wearing conditions. They do not establish a treatment effect for hay fever or demonstrate that nasal obstruction itself improved.

Summary

Compared with the unscented mask, the mint-scented mask produced a greater immediate reduction in perceived nasal discomfort. The later time series also favored the scented condition, but continued improvement over time or further improvement each time the scent was reactivated was not clearly demonstrated.

Self-rated willingness to engage with work or housework also differed. The study shows why evaluating scented products requires separately examining initial comfort, changes over time, and changes after a stimulus is renewed.

The study was a collaboration among Unicharm, Hokkaido University, and Fukuyama University, a relationship disclosed in the conflict-of-interest section. Three of the six authors were affiliated with Unicharm at the time. Funding also came from the Humanities of Coexistence project at Hokkaido University’s Graduate School of Humanities and Human Sciences.

References

Maezawa T, Miyazaki Y, Matsunaga K, Wakasugi K, Shibata A, Kawahara J. Influence of Scented Sanitary Mask on Nasal Discomfort due to Hay Fever and Its Time Course. The Japanese Journal of Ergonomics. 2020;56(1):29–33. Original article (Open full text).