Can Anyone Help Me Find This Book?

I’m aware that there are some websites that are supposed to help with such things but I’ve had no luck on them yet, and thought I’d try some bookish people instead.

I’m trying to remember a book I read when I was probably in my early teens (about 10 years ago, although that’s not to say it was published around them). I obviously don’t know the title or author, otherwise it’d be easy to find these days.

So, what I remember is:

  • It’s set in a theme park, I think the protagonist lives there and it’s run by his parents (though don’t quote me on that)
  • The protagonist is male, I think a bit quiet/geeky and has asthma (pretty sure that becomes a plot point later)
  • There are some shady men hanging around the theme park (vague, I know)
  • I’m pretty sure there’s a new park ride that’s themed around a black hole. The protagonist doesn’t like this ride, and I think in the end it actually takes him up into space and I think he might use his inhaler to help people breathe…
These are all really vague, fuzzy memories but if anyone could name it I’d be thrilled, it’s been bugging me for ages!