The purpose of this thesis was to study quality verification of air quality measurements using uncertainty calculation method. This calculation was based on the year 2014 results of air quality calculation from city of Vaasa. The uncertainty calculation was made for nitrogen oxides (NOx) measurements. The uncertainty calculation for ozone measurements were discovered to be impossible in this case.

The uncertainty calculation was made using calculation matrix from the Finnish Meteorological Institute. The calculation matrix is based on standard SFS-EN 1421. The calculation was carried out using actual data collected from measurement device and measurement environment.

The results of uncertainly calculation was 10.6 % for hourly limit value and 10,3 % for annual limit value. EU directive 2008/50/EY gives limit value not more than 15 % for air quality measurement uncertainty. The measurement uncertainty for NOx meets the directive criterion.