Slow-motion video of raindrops reveals how rain gets its distinctive smell | Hacker News Reader

Slow-motion video of raindrops reveals how rain gets its distinctive smell

washingtonpost.com

159 pointsprateekj20 comments

Wouldn't this provide some evidence for the theory that going into the rain would make you more susceptible to get sick? The range might be limited to close quarters but what about the residual germs and/or viruses that might remain and be aerated again by other raindrops?

It would amaze me to see the aerated particles over time to see if they can be aerated again.

Your logic makes sense.

Two things.

1. In my experience, stories about rain being associated with getting sick, tend to be more related to being cold and wet. We could go on for hours about "folk science" about how cold weather causes sickness. Cold weather is rightly correlated with flu season, reduced levels of vitamin D, and diminished physical activity, all of which probably have strong links to sickness.

2. Your choice of baseline comparison is probably key here. Is going out in the rain "safer" than staying indoors? Staying indoors in a poorly ventilated office building?

From what I can tell, general wisdom today seems to be: unless your immune system is compromised, or you have strong allergic reactions (such as hay-fever), or you live in polluted area, or it is a high ozone day, it is a good to get some exposure to outside air, including the natural germs floating around in it. (Gosh, when I started writing that sentence, I didn't realize how many caveats I would need!)

From the video:

> This research may help explain how rainfall may spread diseases such as E. coli through the environment, and even to humans.

the title for the post article is unfortunate, rain gets its distinctive smell largely from geosmin: https://en.wikipedia.org/wiki/Geosmin

this is just the mechanism by which rain's smell is particularly intense.

I get so excited when it's supposed to rain, especially in the summer.

That ozone smell before, and that earthy smell (which I now now is geosmin) after. It's so awesome.

I wish I could bottle it and do bumps to my noses content.

> I wish I could bottle it and do bumps to my noses content.

I never knew I wanted this before, but now it's all I want. I'd absolutely buy a bottle of that.

I knew I had this link in my bookmarks for a reason...

http://www.demeterfragrance.com/704174/products/Rain.html

In high concentrations, geosmin smells terrible, so be careful. I worked with soil bacteria and I spilled some on my shirt and for months after it would reek horribly after sweating through it, problem was I couldn't identify which shirt it was until after I got sweaty (body heat + moisture), I think. This was a problem because I would go social dancing, change into the shirt, and then after a few minutes notice a horrifying smell on myself.

I hate perfume is the real thing.

http://cbihateperfume.com/

(CB worked at Demeter, there he created all the fragances but left, now has his own company) Read about CB, very interesting profile.

agreed. a bit hyperbole, as some people might already be familiar with: http://en.wikipedia.org/wiki/Petrichor

That's a really sound scientific backing. Now I know what causes the smell after a light drizzle. I'll even link my friends to this article and they'll think I'm cool for knowing that! :)

Thanks!

The title uses the word "how", as in "the mechanism by which", not "whence", as in "where it comes from". In that respect it's accurate, not unfortunate.

I wonder if this is the same mechanisms that releases smells from your hair when you first put your head in the shower and have some strong or notable scents in your hair. One of my favorite parts about coming home from camping trips is showering and smelling the campfire smell again when my hair gets wet.

I'm impressed with how well they make their research public. This could have just been some people with a high speed camera and some mathematical models answering a curiosity and releasing a paper. Like this they present it in a way that even primary schoolers can understand, and even manage to link it to current affairs in the end. 👍

> “Until now, people didn’t know that aerosols could be generated from raindrops on soil,” Youngsoo Joung, a postdoctoral student who worked on the research, said in a statement.

Um, wat? I can't count the number of times I've seen a raindrop or water in general kick up dust, which is also an aerosol: a colloidal suspension of particles dispersed in air or gas. So I find this statement a little surprising.

Sure, the mechanism of bubbles inside a raindrop may be new, but rain kicking stuff into the atmosphere is pretty unsurprising. In AZ, I know several "desert field trips" I went on as a child had us pick Creosote leaves, rub the leaves, and smell the oils released. Voila, rain smell (at least if you're around creosote plants).

Ever walked barefoot on the grass early in the morning when it is soaked with dew. I think there is a lot going on their to give a very distinct smell, which we can all relate to.

Very nice... and right at the end they ruined it: "rainfall may spread diseases like e.coli".

...and they do say "A day without Wine is a day without Sunshine"

Also, how public bathrooms get their distinctive smell...

That is so cool :) best smell in the world

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