Serious global consequences are predicted unless drastic action is taken to prevent further damage to this fragile protective shield. There it absorbs much of the sun's ultraviolet rays, radiation which can cause skin cancer, reduce crop yields, and damage aquatic life. But ozone is also found at ground level, and there it is a problem because it is increasing in quantity - not decreasing. Ground-level ozone is undesirable because it is a serious air pollutant that damages both human health and vegetation. And in Atlantic Canada this ozone is becoming more prevalent in our urban and rural areas.
Natural ozone exists, in low concentrations, at ground level.
Neither source contributes levels high enough to pose serious environmental hazards. But ozone is also a by-product of certain human activities, and that is when it becomes a problem at ground level. Such ozone is a secondary pollutant, produced when several ingredients interact. Ozone pollution is created when sunlight acts upon nitrogen oxides and hydrocarbons - pollutants emitted mainly from automobiles, fossil fuel power plants, refineries, and certain industries. This complex process is known as photochemistry.