Human hair can be a tool for measuring the toxicity of a city, according to London-based architects Deborah Lopez and Hadin Charbel, who have also created a textile made from hair.

​Through their research studio, Pareid, Lopez and Charbel have been analysing hair samples as a way of mapping the levels of pollution across different areas of Bangkok. Samples containing larger quantities of heavy metals indicate higher levels of environmental toxicity.

"Pollution is becoming a gigantic environmental problem," Lopez told Dezeen.

​"We were interested in the capacity of the human body to become a sensor to this, to reflect and record the environment where you live, where you breathe, and where you eat and drink."

The project, called Follicle, started out as an investigation into the potential of hair as an architectural material.

Research suggests that around 6.5 million kilos of waste human hair is produced in the UK alone every year, so Lopez and Charbel felt this material could be an untapped resource for sustainable construction.
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However, after learning about the presence of heavy metals in hair, the pair realised they could also use the substance as a research tool in cities with dangerously high levels of pollution.

They set up their first test station in Bangkok, a city that hit the headlines in early 2019 after high levels of smog forced all of its 437 schools to close.

The architects created an installation at Bangkok Design Week 2019, inviting visitors to voluntarily cut off a small amount of their hair and submit it for analysis, along with details about their day-to-day environment.
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As the hair toxicity is affected by lifestyle choices – smoking and dying your hair both led to increased metal content, for instance – visitors were asked to also provide some anonymous information about themselves.

Although there was some reluctance, Lopez and Charbel were surprised by how many people were willing to donate their hair. They ended up with hundreds of samples.

The toxicology analysis suffered long delays, as a result of the Covid-19 crisis unfolding at that time, but when they finally received the results they were able to see significant links between certain types of environment and certain metals.

For example, people who lived near major highways were found to have a notably higher volume of arsenic in their hair.
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"From that moment we were able to link these two stories together, hair toxicity and pollution in the context of Bangkok," said Charbel.

The architects have been using the information gathered to produce a "toxi-cartography", an interactive 3D map of the city that charts the varying toxicity across different areas. This is available to view on a dedicated website.
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The pair are currently presenting their research within the Spanish Pavilion at the Venice Architecture Biennale.

Going forward, Lopez and Charbel hope to be able to set up test stations in more cities, so that they can start to build up a wider understanding of the links between urban conditions and hair toxicity.

At the same time, the architects are also continuing to explore ways that waste hair can be used in building construction.
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They have used a felting machine to create a hair textile, which has featured in both the Bangkok and Venice installations. Lopez suggests that this felt could be used as an insulating material, or as some kind of acoustic panelling.

The main obstacle to overcome is the stigma surrounding the cleanliness of hair, Lopez said.

"We find it interesting that we feel comfortable with the hair of non-humans, with animal fur, but we feel so disgusted by our own hair," she stated. "We want to find a way to use this material to create something that people feel attracted to."
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Human hair has been used in a number of recent design projects, including designer Céline Arnould's ceramic vessels cast from the hair of her friends and family and a collection of bricks made from hair and manure.

DMDM hydantoin is listed by the FDA as one of the preservatives found to cause the most allergic reactions from the use of cosmetic products. It works as an antimicrobial agent and preservative in cosmetics and personal care products. It's also a “formaldehyde donor.” That means it releases a small amount of formaldehyde over time to help keep products fresh and free from contaminants. The FDA requires certain products to contain an ingredient declaration, but some ingredients may not be specifically identified and instead listed as “fragrance” or “perfume.”
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While the hairstyling industry once revolved around sturdy sprays and stiff gels to keep the latest teased, flipped, winged or crimped locks in place, the segment has expanded over the years to include shine serums, primers to set styles, nourishing mousses, fresh-scented mists and much more.

According to data from Information Resources Inc. (IRI) hair styling gel/mousse sales rose just 0.7% to $1.1 billion in US supermarkets, drugstores, mass market retailers, military commissaries and select club and dollar retail chains for the 52 weeks ended Dec. 1, 2019. However, hair spray/spritz sales slipped 2.5% to $652.2 million.

In the US prestige beauty category, hairstyling product sales increased 6% to more than $252 million for the 12 months ended Nov. 30, 2019, according to The NPD Group. Hair gel sales jumped 14% to $18.4 million, hair mousse/foam increased 6% to $17.4 million, hair spray stayed flat at $65.8 million and  sales of other styling products rose 8% to $150.9 million.
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Scientists say they may have discovered why stress makes hair turn white, and a potential way of stopping it happening without reaching for the dye.

In experiments on mice, stem cells that control skin and hair colour became damaged after intense stress.

In a chance finding, dark-furred mice turned completely white within weeks.
The US and Brazilian researchers said this avenue was worth exploring further to develop a drug that prevents hair colour loss from ageing.

Men and women can go grey any time from their mid-30s, with the timing of parental hair colour change giving most of the clues on when.

Although it's mostly down to the natural ageing process and genes, stress can also play a role.

But scientists were not clear exactly how stress affected the hairs on our heads.

• 'My mum found my first grey hair at seven'
• Why do China's leaders dye their hair?
• ‘My hair is a symbol of pride’

Researchers behind the study, published in Nature, from the Universities of Sao Paulo and Harvard, believed the effects were linked to melanocyte stem cells, which produce melanin and are responsible for hair and skin colour.

And while carrying out experiments on mice, they stumbled across evidence this was the case.

"We now know for sure that stress is responsible for this specific change to your skin and hair, and how it works," says Prof Ya-Cieh Hsu, research author from Harvard University.

'Damage is permanent'

Pain in mice triggered the release of adrenaline and cortisol, making their hearts beat faster and blood pressure rise, affecting the nervous system and causing acute stress.

This process then sped up the depletion of stem cells that produced melanin in hair follicles.

"I expected stress was bad for the body," said Prof Hsu.

"But the detrimental impact of stress that we discovered was beyond what I imagined.

"After just a few days, all of the pigment-regenerating stem cells were lost.
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"Once they're gone, you can't regenerate pigment any more - the damage is permanent."

In another experiment, the researchers found they could block the changes by giving the mice an anti-hypertensive, which treats high blood pressure.

And by comparing the genes of mice in pain with other mice, they could identify the protein involved in causing damage to stem cells from stress.

When this protein - cyclin-dependent kinase (CDK) - was suppressed, the treatment also prevented a change in the colour of their fur.

This leaves the door open for scientists to help delay the onset of grey hair by targeting CDK with a drug.

"These findings are not a cure or treatment for grey hair," Prof Hsu told the BBC.

"Our discovery, made in mice, is only the beginning of a long journey to finding an intervention for people.

"It also gives us an idea of how stress might affect many other parts of the body," she said.

From BBC News

Scientists Think They Know How Stress Causes Gray Hair

• Researchers say they now think they know how stress causes gray hair.
• The hair color change may be linked to nerves in the “fight or flight” response system.
• Experts say stress is only one factor that can cause gray hair. Genetics also plays a major role.

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