This article aims to improve the estimation of the measured PM10 pollutants. In Sofia, there are several air pollution measurement stations. They measure PM10 particles, which are particles found in the air with a diameter between 2.5 and 10 micrometers.

The measurement stations fall into two categories, official stations and citizen stations. The official stations provide reliable measurements, they are better monitored and documented. The down-side is that they are only 5 and they are all concentrated in a single region. The citizen stations represent devices mounted on people homes or properties which measure PM10 particles. There is a whole network of such devices. They are many in number and provide a good coverage of the city. The problem with those measurements is that they are biased because of many local factors. Therefore the measurements form the citizen stations are not as reliable as those from the official stations, but on the up-side they are many in numbers.

In this article we define a method to reduce the bias of the measurements from the citizen stations.