PAH compounds, or polycyclic aromatic hydrocarbons, are created through incomplete combustion. The target value for the PAH compound benzo(a)pyrene (1 ng/m3) may be exceeded in some places in the detached housing areas of the Helsinki metropolitan area where a lot of wood is burned. The effect of traffic emissions on the concentrations is quite small. Many PAH compounds, such as benzo(a)pyrene, increase the risk of cancer.
In the Helsinki metropolitan area, PAH compounds are monitored in Kallio and Mäkelänkatu Street, as well as in detached housing areas in Vartiokylä. In 2020 PAH combounds were monitored in Pirkkola and Ylästö. In 2021 monitoring takes place in Luukki and in a detached house area in Ruskeasanta. Elsewhere in Uusimaa, PAH compounds were monitored in a detached house area in Tuusula in 2020 and monitoring continues in Lohja in 2021.
You can examine the monthly concentrations of benzo(a)pyrene in the Helsinki metropolitan area and elsewhere in Uusimaa from the graph below. The results are updated every three months. Concentrations are high when the annual average is more than 1 nanogram per cubic metre of air (ng/m3).