food packaging doesn't produce microplastics, and you inhale tire dust

Doesn't it? Got any evidence for that claim?

Of course it does - plastics used in packaging scratch easily. That's enough to produce microplastics.

Additionally polypropylene degrades under sunlight, becoming brittle. The process takes several months.

oh, sure, they can produce microplastics after you take the food out. but you aren't going to get plastic dust in your lettuce

the most common plastics used in packaging are pet, polypropylene, and polyethylene, which have exceptional elongation at break. when you scratch them, you don't produce microplastics; you produce a burr on the surface

You're gonna get it in your yoghurt and food packed in tupperware though, as metal utensils can and will scrape some of the plastic off.

Anyway, they're already present in tap water, so your lettuce is also already infused with microplastics.

that's a good point about the tap water, and you're probably right about polystyrene yogurt cups and tupperware, though i still think you won't find any evidence of it unless you do the experiment yourself