Clean rooms today are highly technological solutions with very high demands on the air cleanliness level. Using kerosene heater for cooking as well as cigarette smoking is important indoor source of fine and coarse particles. It is important to estimate the level of air cleanliness in the cases of new production or reconstruction of a clean room. The air cleanliness level in a clean room is dependent on the quality of the supply air, contamination sources and the design of the ventilation system. By making proper design of air conditioning and ventilation system, the air cleanliness level can be controlled. The number of particulate matter also depends on humidity and temperature in the room at different times. In this study, indoor and outdoor air quality has been measured by an optical particle counter and experimental studies have been carried out to make the indoor air free from particulate matter. Different methods have been prescribed to make the indoor air free from particulate pollution. The results obtained from this experiment can be helpful to take necessary steps to keep the indoor air cleaner.