yes, 空氣流通 very important. i walked around in sheung wan's wing on department store's basement for around 20 minutes - the place was so stuffy, with all the cooking utensils demo, "oil smoke", and poor air ventilation - and when i got back to the ground / street, i could not continue shopping around. the 20 minutes in the basement wore me out and left me dizzzzzzy
i discovered one more thing yesterday, that is, if i am hungry and standing at the same time, i will be dizzy too