This Regulation of the Minister of Environment, which is composed of 16 paragraphs and nine Annexes, implements art. 90 point 3 of the Environment Protection Act and establishes: (1) methods and scope of the evaluation of levels of substances in ambient air; (2) requirements for the quality of measurements and other methods of air quality assessment, including mathematical modeling of transport and transformation of substances in the air; (3) upper and lower threshold values for certain substances in ambient air and the permissible frequency for exceeding threshold values; (4) required measurements, divided into continuous and periodic measurements; (5) criteria for the location of the sampling points; (6) minimum number of fixed sampling points; (7) cases when air quality assessment shall be made with individual measuring methods; (8) reference methodology; (9) requirements for documentation regarding justification of the location of measuring points; (10) criteria for the validation of data on substances in ambient air; (11) scope of measurements supporting the assessment of air quality, in particular the scope of the analysis of the chemical composition of dust.