8. To assess the contribution of benzo(a)pyrene in ambient air, each Member State shall monitor other relevant polycyclic aromatic hydrocarbons at a limited number of sampling points. Those polycyclic aromatic hydrocarbons shall include at least: benzo(a)anthracene, benzo(b)fluoranthene, benzo(j)fluoranthene, benzo(k)fluoranthene, indeno(1,2,3-cd)pyrene, and dibenz(a,h)anthracene. Sampling points for those polycyclic aromatic hydrocarbons shall be co-located with sampling points for benzo(a)pyrene and shall be selected in such a way that geographical variation and long-term trends can be identified.