Is your garage actively ventilated? Mine (in my previous house, I live in an apartment now) was a closed room with a pulldown door (always closed) and a window

Is your garage actively ventilated? Mine (in my previous house, I live in an apartment now) was a closed room with a pulldown door (always closed) and a window that didn't open. It's not hermetically sealed, but how confident are you it wouldn't become saturated with N2 gas?