HOW TO GET FRESH AIR 23 



whether or not enough air comes in to supply all who 

 need it. 



If everything is shut you are breathing impure air 

 and you ought to do something about it. 



Nobody can tell exactly how wide open windows 

 need to be, because all depends on the size of the room 



DRIVING AIR OUT OF A ROOM 



and the number of people in it ; also on the size of 

 the windows and the direction of the wind. When a 

 breeze blows, an opening of an inch or two may be 

 enough, but on a quiet day the windows should be 

 wide open. 



Some people think that the hall door will give all the 

 air they need, yet they do not take pains to see that 

 the hall itself is getting outdoor air. 



