Points out that traffic pollution in urban areas inevitably has an impact on the indoor air quality (IAQ) of buildings that must therefore use polluted air for ventilation. Provides guidance on the use of ventilation control to reduce the effect of outdoor pollution on IAQ. Explains how to determine if outdoor air quality is poor, how to assess alternative ventilation control strategies if outdoor air quality is found to be poor and how to select and implement an appropriate control strategy. Advises on suitable sensors and sets out eight different strategies and a decision tree to help select the most appropriate strategy. Includes control strategy flow charts for each one.