Bill Gates
Bill Gates takes it all in via a glass sniffing tube. (Via YouTube)

Bill Gates’ business sense has a lot to do with why he is who he is, but it’s the billionaire Microsoft co-founder’s sense of smell that was put to the test in his latest effort to find a solution to sanitation problems in the world’s poorest countries.

Gates has long sought better ideas around the taboo subject of toilets — including being a champion of building better ones. And his nose wasn’t first to the fight in the battle against poop — his sense of taste took a giant leap of faith in science when he drank water converted from human waste last year.

In a new blog post on Wednesday, Gates writes about the efforts of a Swiss fragrance and flavor company called Firmenich, which is partnering with the Bill & Melinda Gates Foundation to tackle the world’s deadly and costly sanitation problem. He says about 800,000 children under age 5 die each year from diarrhea, pneumonia, and other common infections caused by unsafe water and sanitation.

Gates writes about how millions of new toilets are being built around the world to curb rampant, open defecation, especially in countries like India. But many of the toilets are not being used because they smell bad, and people revert to relieving themselves in the open air.

Firmenich was determined to isolate what actually causes these toilets to smell so bad. And before you say, “I’m no billionaire, but I’d guess it’s the poop,” there’s more to it than that.

Gates writes that toilet odors consist of “200 different chemical compounds arising from feces and urine that change over time and vary depending on the health and diet.”

Firmenich researchers identified four main chemical culprits: indole, p-cresol, dimethyl trisulfide, and butyric acid. Scientists then recreated the odor using synthetic compounds, to make what Gates calls a “poop perfume.”

To combat the smell of its own “poop perfume,” the effort went beyond the common response, which is to cover unpleasant odors with more pleasant ones — like when you (OK, not you, your roommate) freshen things up with a bathroom spray. Firmenich addressed the problem on a molecular level, Gates says. Of the 350 olfactory receptors which relay smells between our noses and brains, just a handful allow us take in the nasty stuff. Firmenich sought to cut off these particular receptors with an odor-blocking fragrance.

Taking one for the team yet again, Gates got a whiff of the “poop perfume” first, which he said “smelled as bad as the worst toilets I’ve ever visited.” Next, he put his nose up against the same stale feces and urine smell, but this time it was mixed with the odor-blocking fragrance. He said it smelled “pretty good” and had no evidence of the previous stinky odor and was instead more like a pleasant floral scent.

Gates’ hope is that continuing innovation from companies like Firmenich will lead to further solutions to improve the health and dignity of people living in places where the need for better sanitation is so great.

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