1 Allergic reactions and sensitivities to certain foods may cause a canker sore to develop. Allergic reaction to certain types of bacteria found in the mouth may also result in this type of mouth ulcer.  Celiac disease sufferers may experience canker sores.
One of the biggest sources is called nonpoint source pollution, which occurs as a result of runoff. Nonpoint source pollution includes many small sources, like septic tanks, cars, trucks, and boats, plus larger sources, such as farms, livestock ranches, and timber harvest areas.ne of the biggest sources is called nonpoint source pollution, which occurs as a result of runoff. Nonpoint source pollution includes many small sources, like septic tanks, cars, trucks, and boats, plus larger sources, such as farms, livestock ranches, and timber harvest areas.
The largest net source of tropospheric ozone is influx from the stratosphere. Large amounts of ozone are also produced in the troposphere by photochemical reactions, the amounts increasing with high levels of air pollution.Much of this ozone, though, is balanced by photochemical ozone destruction.he largest net source of tropospheric ozone is influx from the stratosphere. Large amounts of ozone are also produced in the troposphere by photochemical reactions, the amounts increasing with high levels of air pollution.