INDOOR CONCENTRATIONS OF AMMONIA AND THE POTENTIAL CONTRIBUTION OF HUMANS TO ATMOSPHERIC BUDGETS

Simple passive diffusion tube samplers were used for the determination of ammonia concentrations in homes. The gas was collected by molecular diffusion on sulphuric-acid-impregnated glass-fibre discs and subsequently determined spectrophotometrically. In a survey of 10 homes, ammonia levels were found to average 39, 37 and 32 mug m-3 (NH3 as N), respectively, in kitchens, living rooms and bedrooms. The maximum concentration found was 85 mug m-3 in a kitchen and a minimum of 13 mug m-3 in a kitchen and a living room. These values were obtained with sampling periods of at least 1 week. The relative constancy of ammonia levels throughout the houses surveyed may be explained on the basis that the occupants themselves are the main source of the gas. The potential human contribution to atmospheric ammonia is discussed along with its implications for ammonia budgets in the atmosphere.