Field tests of a linear gradient system for exposure of row crops to S02 and HF

Field methods used for air pollution research with plants

“…Another type of chamberless fumigation system is the linear gradient system (Shinn et al, 1977;Laurence et al, 1982;Reich et al, 1982). The system consists of three perforated polyethylene tubes connected to a blower and pollutant-mixing chamber for exposure of four rows of plants.…”

Field techniques for exposure of plants and ecosystems to elevated CO2and other trace gases

“…Also, the exposure plots were surrounded by a 0.6 m high barrier to help minimize the incursion of outside air into the plot. A similar system was designed to expose row crops to O 3 , SO 2 , and HF in multiple pollutant exposures (Laurence et al 1982;Reich et al 1982). Thompson and Olszyk (1985) designed another system for a variety of uses including ambient air exclusion, or for linear gradients of ambient air or SO 2 .…”

“…The U.S. Department of Energy's Argonne National Laboratory developed its own ZAPS capability (Miller et al 1980), as did the University of British Columbia, Canada (Runeckles et al 1981;, the University of Nottingham School of Agriculture, U.K. (Greenwood et al 1982), and the U.K. Central Electricity Research Laboratories . A related open-air fumigation system to provide linear gradients of exposure to a pollutant with air exclusion methods was designed by Shinn et al (1977) and modified by Laurence et al (1982) and by Reich et al 1982). McLeod and Fackrell (1983) and McLeod and Baker (1988) reviewed methods of open-air fumigation.…”

The cost of crop damage caused by ozone air pollution from motor vehicles

“…Open-field systems are large experimental field units on which ozone concentrations are controlled by a series of pipes that emit ozone precursors (nitrogen oxides and hydrocarbons) (Laurence et al, 1982). It is difficult to control ozone levels in these systems because the levels are affected strongly by ambient factors such as wind and temperature.…”