That's rough and you need to consider your wife and her feelings. It's 33 degrees everyday here, what is she going to do? HK can get lonely and boring for those not working and having a budget on money can make it difficult.
Groceries, do you eat a good portion of meat or light portion. When my helper cooks and with soup veggies 2 meats full meal it is easily $120 per meal. Don't forget lunch during the workweek. Nights out with colleagues and friends, happy hour, nice meals with the misses, late night taxi home now and then. It all adds up.
Yes you can live on it, but it isn't ideal. I would ask the company to provide a housing allowance otherwise it isn't worth it. That's my opinion, others will say differently.
And yes the air is bad for sensitive people. That's torture. Then you need to add medical coverage if not included at work.