I have 2014 sonata with nitrogen tires (the tires air port has a green cap on them). I think two tires need a little air. If I put regular air in these is the car gonna blow up? Or should I take the car to the dealer so they can say they're putting nitrogen in it and tell me 100 other things I need to do the car?
In short - No, you can safely top the tires up with regular air. There's absolutely no difference in ride quality and handling between the two under similar pressure. Having said that, filling tires with nitrogen has a few benefits-
Nitrogen filling systems usually supply moisture free nitrogen gas which results in
- lesser variation in pressure with tire temperature changes.
- lesser chances of corrosion to the valves and rims since both the ingredients required for it are absent- O2 and H20.
Another reason to consider sticking with nitrogen is that if ever you decide to go back pure nitrogen , you'll need to bleed all the air out and replace it with nitrogen. This will take a few cycles to purge all the air out and may cost you considerably more than just topping it up.
You don't need to take it to your dealer, just look for any fill station or tire shops that have a nitrogen fill station.