Last December there was much written about the case for and against open windows Winter and Summer. Fortunately we live in a Queensland (timber walls and on stilts (stumps they call them here). Brisbane suffers from high humidity in the Summer especially before and after rain (this year has been noticeably wet like the UK). We have ceiling fans (and a-c which we don't use that much). My wife likes to open the window - just above our heads whereas I like the ceiling fan. I guess we have compromised and take it in turns - when the fan is on...the OH snuggles down so much I sometimes wonder if she is in fact in bed (LOL). I also have an air purifier which helps expecially when we have grass fires which we did serveal times this year. My nose it now highly attuned to any hint of smoke (some people in the area have wood fires in Winter). It has got so bad at times that I watch TV wearing a mask. Heaven knows what it is like for those living in Beijing and Shanghai - not a place I would like to visit anytime soon!