Device uses wind to create ammonia out of air

What is so dangerous about it compared to lets say a gasoline engine converted to use LPG or Methane? There are many of those in Europe where I live.

You mean aside from being a colorless toxic gas that will kill you in as little as 5 minutes?

Just like propane, nitrogen, laughing gas, and methane ... I don't follow?

Yeah, ammonia leaks are much more nasty than methane or hydrogen leaks. Methane, especially in LNG form, is quite safe compared to ammonia. LPG is even more stable than LNG and requires lower pressures. With that said, hydrogen leaks are "fun" because large ones usually self ignite and burn with a hot but mostly invisible flame. But hydrogen itself isn't toxic. Similarly, methane and propane aren't directly toxic.

Basically, an ammonia leak will kill you. By itself. The others are only a problem if they're the right concentrations to ignite. That's a relatively high concentration and a larger leak. Much smaller leaks of ammonia are deadly.

It's still a good solution for some things, but it's a bad solution for consumer vehicles like cars for that reason.

Ammonia is much more caustic, toxic, and explosive than LPG and incidents involving it like the Minot derailment tend to be significantly worse.

https://en.wikipedia.org/wiki/Minot_train_derailment

I'm guessing you have never gotten a snoutfull of ammonia? Relatively low concentrations in air feel like asphyxiation. It also hangs around near the ground rather than floating upward.

Those others are effectively asphyxiants: they'll kill you by displacing oxygen, leading to you collapsing and dying if not rescued, eg by being dragged clear or having ventilation improved. Ammonia is a caustic: airway constriction and oedema will get you at modest concentrations, weeping eyes may hamper your escape, and if rescued you may have lasting damage.

I think the concern here is somewhat misplaced...ammonia powered passenger vehicles are probably a bad idea.

But there's no reason that needs to be true for e.g. automated shipping industries. The danger to the water seems relatively low as well, as water dilution seems to be one of the best ways to deal with spillages. I'm uncertain the environmental repercussions, however it does seem to be the case that aquatic mammals and humans have natural methods of elimination, making it a game of concentration and dispersion vs e.g. an oil spill that is both highly toxic and nearly impossible to properly clean up.

The majority of other applications are industrial (fertilizer, energy storage): there are major issues with our current distribution systems, cheap ammonia batteries could be the key to efficient electricity and hydrogen production and distribution.