Environmental interactions

Unfortunately, crops are rarely exposed to only one pollutant. Plants growing in high O₃ concentrations may also suffer injury from sulfur dioxide, nitrogen oxides, acid rain, and UV radiation. The net effect of exposing plants to more than one pollutant may be equal to, greater than, or less than the sum of their individual exposures. The effects are further complicated by crop type, time of exposure, weather conditions, previous exposure, and other environmental stresses. Consequently, recent studies have only provided some knowledge about the potential effects of O₃ on a few major crops and regions.

Although CO₂, N₂O, CH₄, and O₃ have attracted much attention recently, agriculture also releases other materials into the air, including ammonia, other odors, aerosols, nitrogen oxides, and pesticides. As well, agriculture may be affected by changes to stratospheric O₃. Many of these issues have not yet been thoroughly studied in Canada. Our main aim is to identify the potential issues and point to some possible effects.