How to stay cool the Japanese way

One of the many exhibitions of refrigeration products in Tokyo

Cooling products such as face masks are widely available in Tokyo

Face masks remain ubiquitous in Japan, even outdoors on 35C days, so I try some that promise relief from the heat.

It takes a while to get used to a menthol and eucalyptus based mask, and not just because of the cough drop smell.

The sensation gets stronger the longer I wear it, to the point where I almost feel like my cheeks are burning. But my face is cooler.

So do my arms, after using cooling wipes that leave a surprisingly strong tingling sensation on the skin.

These are just some of the dizzying array of personal products sold in Japanese cities, where summers are very hot and humid.

The concentration of tall buildings limits shade and exacerbates the urban heat island effect, where buildings and streets absorb and retain heat and become significantly warmer than surrounding areas with shade or green space.

According to climate researcher Kazutaka Oka, the temperature in Tokyo has risen by 3 degrees Celsius over the past century. Of this temperature rise, 1C is attributable to climate change and 2C is due to the urban heat island.

The use of air conditioners is critical to save lives as temperatures soar. However, “air conditioning is one of the drivers of the urban heat island,” says Dr Oka. This creates a pressing need for more energy efficient air conditioning and more renewable energy sources.

Dr Oka is responsible for work on health impacts and adaptation at the Climate Change Adaptation Center, part of the National Institute for Environmental Studies in Tsukuba.

Neck fan worn in Tokyo subway

A commuter on the Tokyo subway wears a fan to try to stay cool

As we speak at his institute, a technician is repairing the elevator. He wears a jacket that contains two fans.

This is an increasingly common sight in Japan. Electric hand fans have grown in popularity since 2019, the year after a punishing heat wave. And this year Japan was hit by an unprecedentedly early heat wave.

The early end of the rainy season combined with low energy reserves, prompting the government to ask people to reduce their electricity use.

Personal cooling devices could help with this. In general, cooling people instead of cooling rooms with air conditioning can reduce electricity at least tenfold.

The June 2022 heatwave has seen an explosion of personal cooling products, including UV-blocking umbrellas and face cooling sheets.

The Japanese market has so many niches that there are cooling products aimed at babies, cyclists and outdoor workers. Now there are even portable fans for dogs.

Dr Oka believes that cooling jackets could be a useful way of adapting to higher temperatures, which of course also need to be contained. But he emphasizes that technological measures are not silver bullets.

In particular, she says, products that use mist can provide a cooling effect, but some people complain that they increase humidity.

The ¥2,580 (£16, $19) portable fan I buy from a grocery store is heavy on my neck. In 38C weather, during the second of Japan’s 2022 summer heat waves, it’s like the fan is stirring around the hot air.

Cooling towels on display outside a Tokyo store

Sales of cooling towels have tripled over previous years, according to a retail employee

A trial of cooling towels, which are meant to be wet and then worn on the skin, found that skin and body temperatures immediately dropped by 1.8C to 2.8C – so they can provide some immediate relief.

They are also extremely popular in Japan’s current hot weather, with retail worker Nana Nihei reporting sales are up 200% compared to previous years.

Yoshinori Kato is head of product development at Showa Shokai, which, for the past 21 years, has been manufacturing an ever-expanding range of anti-heat measures,

There have been three distinct phases in sales trends, says Mr Kato. Their first product was salt tablets, in response to reports that dehydrated construction workers were licking the soil to get the necessary salt into their bodies.

The second phase was the development of portable cooling and mister systems.

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The current phase focuses on products that cool people rather than environments. The most popular products now are vests with built-in fans. But after about 35 C, these fans become counterproductive due to the hot air intake.

“To address this, we need a product that can instantly cool the body,” says Mr Kato.

So he shows me a light (590g) black vest to which three cooling units are attached. The metal side absorbs heat, while the other side emits heat.

Although this can result in the external environment heating up, like air conditioning, Mr Kato says the product can operate in temperatures up to 40C, including high humidity.

Many of Showa Shokai’s end users are construction workers and engineers, and Mr Kato says many people have told the company they need something more versatile. Indeed, when I strap on the vest and walk around the Showa Shokai office, I’m amazed at how mobile the garment is.

Improvements in cooling clothing such as these will face a trade-off between portability and power source power. The cell phone battery that powers this vest is the size of a small power bank and fits in a pocket. It currently lasts only 3.5 hours at full power.

Given the battery life and the price of 30,000 yen, these products are more suitable for use for short periods of time and for purchase by employers rather than manual workers themselves.

A self-employed builder I speak with uses a vest with fans, combined with an ice pack, while on the job. But the battery is expensive and he has to buy such devices himself, so he saves it for very hot days.

It is important to keep in mind the limitations of such technology.

It would be counterproductive for employers to turn to technology as a way to ensure employee productivity, instead of dealing with workloads and rest breaks during extreme heat.

Another issue is that the people who are most at risk of heat stroke are not the ones who use these products the most.

Personal cooling devices are mainly used by younger people and manual workers, although it is pensioners who are most at risk as temperatures in Japan continue to rise.

Wakako Sakamoto is assistant chief of environmental safety at Japan’s Ministry of the Environment. He says that in Tokyo in 2021, most people who died of heatstroke were aged 65 or older and were indoors without air conditioning on at the time.

A cyclist rides with an umbrella in Koshigaya

Low-tech umbrellas ‘scientifically proven’ to keep out the sun’s rays and heat

While not everyone has the space or money for air conditioning, there are still many seniors with air conditioners installed who don’t use them in extreme heat. “We ask these people to use air conditioning,” urges Ms. Sakamoto.

Her colleague Takahiro Kasai, who is in charge of heat countermeasures at the Ministry of the Environment, adds that some of the most tried and tested personal cooling devices are relatively low-tech.

“An umbrella is something that is scientifically proven to block the sun’s rays and heat. It also covers the whole body and creates shade for yourself,” he says.

But for people who have those basics covered, personal cooling devices — whether they’re umbrellas, towels or portable fans — can be a way to stay comfortable and healthy outside the home.

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