I can't believe your toilet is located OUTSIDE ON YOUR BALCONY!!!!

But I CAN believe it, due to experience. In Sichuan counties that is common in older apartments. At least, the rooms aren't smelly despite the hot, humid summer weather there. By contrast, more modern Chinese apartments usually have their WCs constructed without windows. So, we have no way to clear the air if there is no air conditioner/extractor fan in the WC.
I believe air pollution in Beijing right now is very serious due to recent weather conditions there. It seems that's much worse a problem than a temporary bad smell that you couldn't bear!