Intestinal metaplasia is also a common in Barrett esophagus. It this condition it is the esophageal squamous epithelial cells that undergo metaplasia. Approximately, 60% of esophageal cancers diagnosed in the U.S. stem from focal intestinal metaplasia.
Ozone Emission Sources. Emissions contributing to ozone formation come from many areas. The main emission sources categories are: On-road - cars, trucks, and buses. Off-road - aircraft, locomotive,etc. Non-road - construction, agricultural equipment, etc. Point - cement and power plants.
The main cause of ozone depletion and the ozone hole is man-made chemicals, in particular man-made halocarbon refrigerants, solvents, propellants, and foam-blowing agents (chlorofluorocarbon (CFCs), HCFCs, freons, halons), referred to as ozone-depleting substances (ODS).