Studies realized to assess the levels and varying profile of PAHs in
some of the largest cities in the world, showed that the concentration
of these pollutants are higher in winter, than in other seasons of the
year (Ravindra and Van Grieken, 2001). The seasonal average concentrations
of PAHs for each season of the year, since the beginning of monitoring,
are given in Fig. 4. The weather seasons presented are autumn
(September–November), winter (December–January), spring (March–
May) and summer (June–August).