ABSTRACT
In order to evaluate the success rate of Comprehensive Plan for Reduction of Air Pollution [1999-2005] of Tehran city, this study was carried out to measure the levels of carbonmonoxide pollutant in this city during the execution of the mentioned plan. Data from Air Pollutants Measuring Stations in Tehran were analyzed using Excel software in which the daily levels of carbon monoxide were formerly extracted from 8-hour data and using daily rates, therefore, the relative monthly and annual rates were calculated. Studying the process of changes in carbon monoxide level in Tehran city, we may conclude that execution of this plan was not effective enough to reduce the level of CO pollutant to the extent expected. Nevertheless, due to the increasing trend in number of motor vehicles, [which are considered to be the main source for producing the CO in this city] it seems that it has, somehow, prevented the increase of this pollutant. Due to the increasing trend of CO production in Tehran city and consequent dissatisfaction from this trend, reviewing the "Comprehensive Plan for Reduction of Air Pollution" which has been executing since 2000, is of indisputable importance. This may provide us another apportunity to control the level of CO pollutant in the remained years of Plan [2006-2010]