That's too easy, glutamate is neurotoxic in high doses.

What about sugar?

pm2.5 is a metric used in assessing air quality. Amino acid aerosols are not a source of air pollution.

amino acids droplets are pm2.5. pm2.5 refers to the particle size.

See what i wrote in the other thread... https://news.ycombinator.com/item?id=45784538

Pm2.5 is a specific particle size, yes, we do agree on that. Importantly, it is also a common measurement used in assessing air quality. In that context it is typically composed of particles from a set of common sources, like wildfires, industrial sources, automobile pollution, etc…. It is, in the context of air quality monitoring, never composed of amino acids. It seems valid to make claims about pm2.5 and health, even though the claim does not distinguish wildfire pm2.5 from pm2.5 from automobile pollution or other sources. Maybe I misunderstood you to be saying otherwise.

Yeah but which substances/sources is not given when you just say "Pm2.5". Which is what the article did. And depending on the actual substances you get different health effects or none at all.