Besides the concentrations of air pollutants, HSY also monitors weather factors. Variables to be monitored are the outside temperature, wind speed and direction, and the relative air humidity.

The monitoring sites are located in Pasila and Ämmässuo. The monitoring site in Pasila is at Asemamiehenkatu 4, where the measuring height is 53 m above the earth’s surface and 78 m above sea level. The monitoring site at Ämmässuo in Espoo is located in the area of the HSY Waste Treatment Centre.