Outdoor sources of indoor air pollution

Conservation measures that seal a building, such as storm window installation, can significantly reduce its energy requirements. These measures also protect its occupants from air pollutants having outdoor sources but amplify any harmful effects of those generated indoors. Which effect is greater?Since it is inadequate to consider pollution levels constant, we assume that they follow daily cycles and can thus be well represented by Fourier series. We conclude that the indoor concentration of any pollutant generated solely outdoors also follows a daily cycle but its maximum lags behind and is lower than the outdoor maximum to an extent depending in an inverse manner on v, the air exchange (ventilation + infiltration) rate. A simple measure of the daily variation of pollutant concentrations and indoor production rates can be derived from their Fourier series and used to test whether these quantities can be assumed constant.Although average daily indoor and outdoor pollutant concentrations of any pollutant are the same if there are no indoor sinks, lowering v will still protect a building's occupant if: (1) the outdoor peak or variation above its average is much greater than its average, and (2) the peak is short-lived.Lowering v probably raises indoor average and peak pollutant concentrations from all indoor sources by at least as much as it lowers only peaks from just one outdoor source, rush hour traffic, thus increasing indoor pollutant levels.