Points out that water treatment chemicals from cooling towers are emitted in both the gaseous phase and as pollutants dissolved in or suspended in water droplets. A qualitative evaluation of exhaust dispersion and droplet deposition rates associated with cooling towers is necessary when conducting an overall review of the environmental impact on indoor air quality. Identifies source emission rates to be used in assessing emissions of chemical additives in cooling towers, presents provisional design criteria for evaluating the impact of the chemical additives and evaluates alternative methodologies for quantifying impact concentrations. These include numerical models, physical wind tunnel simulations and computational fluid dynamics simulations.KEYWORDS: Cooling towers, indoor, air quality, contaminants, outdoor air, gases, aerosols