An Open‐Top Field Chamber to Assess the Impact of Air Pollution on Plants

Reasonable air pollution control policies depend upon a comparison of the costs of air pollution losses with the costs of controls. Present estimates of national economic losses to agricultural and ornamental vegetation are based primarily on field observations and partially on growth and yield data obtained from closed‐top field chambers and greenhouses. This research describes the design and evaluation of an open‐top field chamber that was developed to provide an environment more closely resembling ambient conditions than the environment found in closed‐top chambers.

Temperature and relative humidity within open‐top chambers were similar to ambient conditions. Direct sunlight reached the plants for a portion of each day and rain entered, although not always uniformly over the chamber base. Chambers receiving charcoal‐filtered air protected sensitive ‘Bel W₃’ tobacco plants (Nicotiana tabacum L.) from ambient ozone concentrations. Plants growing in chambers receiving unfiltered air or in ambient air plots were severely injured.