Urban Air Pollution UNEP/GEMS Environment Library The value of this volume is the summary of the GEMS/Air assessment on the levels and effects of five of the most common and ubiquitous air pollutants: sulphur dioxide, nitrogen oxides, carbon monoxide, lead and suspended particulate matter. Data is drawn from 50 countries. This publication also presents an historical overview, the causes and effects and the sources of pollution. This is the fourth volume of the UNEP/GEMS Environment Library Series. Book Ordering Information:    Sales Number: E. 95.III.D.51     ISBN: 92-1-100576-0     No.4     Pages: 40pp. Price: $10.00 [Environment Main] [Subject Index] [Alphabetical Index] [UN Publications Policies] Copyright © 1997 United Nations