The study focuses on indoor air quality (microclimate, chemicals) in industrial premises. The health risks are determined. A model with numerical criteria is offered to assess the level of occupational hazards (indoor air climate) using a simple/flexible risk assessment method. Practical examples and the results of measurements of microclimate (temperature, humidity, and velocity of the air) and chemical concentrations in the workplace air in five industries (mechanical, printing, wood, plastic and clothing industries) are presented. The connections between risk levels and possible health damages are presented. In the wood processing industry the concentration of solvents: toluene (1- 941 mg/ m3); xylene (2.5-347 mg/ m3); butanol (0.5- 285 mg/ m3) and styrene (1-208 mg/ m3)) is considered to be unacceptable risk for workers’ health. The model is presented for taking into consideration the concentration of chemicals in the air of the work environment and possible negative health effects. The microclimate is under control except during very warm climate in summer. The chemicals are under control in printing, mechanical (except welding in closed workrooms), and clothing industry. The simple/flexible risk assessment method is suitable for enterprises processing materials or handling chemicals in some stages, but cannot be applied for chemical plants where several other factors should be taken into account.