Not sure anymore. The lesson we were taught just basically said that it damages your lunge if you breath in too much. There were some other interesting thins in that lesson. Basically that cars release not only co2 but also pure c into the air which binds o3 elements into co2 and o2. Which is why in cities and region with more traffic less o3 can be found. O3 is also more common and really sunny days. But please take this with a grain of doubt as this was some years ago.
I don’t why people buy multiple phones. Over the span of few years. Is it not a hassle to always set them up?