WHO <br/><br/>
Air Quality Guidelines : Global Update 2005 : Particulate Matter, Ozone, Nitrogen Dioxide and Sulfur Dioxide 
WHO 
 -  WHO Regional Office for Europe  2006 
 - On-campus e-Book by ebrary under Digital Library Program of Higher Education Commission (HEC) of Pakistan 
<br/><br/><label>ISBN: </label>9789289072908     
<br/><br/><label>Subjects--Topical Terms: </label><br/>Engineering & Technology