Nanoparticles in European Cities and Associated Health Impacts - Urban Air Quality in Europe - page 353

Fig. 3 Typical average PNCs at roadside environments in various European cities. Data has been
taken from the references listed in Table 1
treatment for particle losses within them (see Table 1 ). Highest PNCs are found to
be on the sampling location adjacent to the roadside having a high traffic volume
(i.e. at Birmingham and Zurich sites), where the vehicle sources are close to the
sampling location. It is also worth nothing that even though traffic is the main
source of PNCs, new particle formation by photochemistry in Mediterranean
regions may also be a significant source [ 93 ]. This is clearly evident from Fig. 3
that Barcelona shows the fourth highest PNC despite the fact that the sampling
station is near traffic, but not such a roadside location as Marylebone Road in
London or Zurich. The ultrafine size range of particles contributes about 80% of the
PNCs and their concentrations are elevated near the sources, majorly contributing