The sources and long term effects of the most troublesome pollutants are described. Hydrogen sulphide is produced by decaying organic matter and is always present in at least minimal amounts. Its most significant effects are on silver metal and lead compounds. Sulphur dioxide is produced by the combustion of fossil fuels. It has a detrimental effect on leather, paper, and other organic materials. Water in high concentrations in the atmosphere may be considered a pollutant. Organic compounds may be given off by many types of materials used in conjunction with storage and display. Suggestions for reducing or eliminating pollutants are given.