允许空气进洞以防潮湿

取决于年份属性
空流应楼下
除非有火场

混凝土楼层 免用

If you have concrete floors i am assuming your airbricks are through the walls then you can block one side of the air brick (the inside) and leave the outer airbrick as it will still circulate air into the cavity it does not need to go all the way through unless you have windows in the kitchen you cannot open for some reason an airbrick that goes all the way through is only to circulate air into the room