The importance of museums and monuments in Nigeria and elsewhere in the world is not far-fetched. They provide rich evidence and concise information regarding old civilizations and cultures of different peoples. The safeguarding of monuments is one of the most urgent priorities, involved in the good preservation and conservation methods of all monuments and museums that have important artistic and historic values. The Museum houses monuments, which are either stored or exhibited. Artifacts in the museums need a good environment, which includes an atmosphere free of dust and pollutants. The air (outdoor and indoor) unfortunately, is often polluted. The pollutants are either from anthropogenic or non-anthropogenic source. Deterioration of museums and monuments by the pollutants is usually slow and progressive, a prolonged exposure can cause severe or minor damage to a wide range of items. If problems due to pollution are identified, what needed to be done is to test for the pollutants and to measure their quantity. To do this, samples of the area would be collected, analyzed and the results will be compared with published standards and damage threshold levels. In this paper, an overview of the types of museums, pollutants, damage and deterioration that are caused to people, materials and monuments, instruments for monitoring and steps to reduce the pollution effects was discussed. It is hoped that this paper will inform or assist Nigerian museum personnel in tackling pollution problems likely to destroy the cultural heritage of the nation.