MacBook Air 2019 13inch- whooshing/buzzing sound after being turned on

Hmm, still sounds like there is debris in the internal fan to me. There should be a vent in the back of the laptop. Look for any "dust bunnies" or other debris. If any are present you will want to vacuum them out. However, to fully inspect the internal fan you would need to open the laptop to get at it.

Since this is a bit of an "adventurous" route, you may be better served by taking it to your local Apple Store or Apple Authorized Service Provider to have them take a look and provide you with your options.

Not a lot of information to go on with your post, but if I had to make a guess, it could be that your laptop's fan may be clogged or damaged.

Are you seeing any error messages? Is your Mac running "hot?"

The more information you can provide us, the better we can try to assist you with a solution; otherwise, all we can do is suggest that you contact Apple Support directly for further help with this issue.