Table 3 compiles PM10 and PM2.5 concentrations, as well as
OC and ECmass fractions, for different road tunnels around the
world. The PM10 levels measured in Braga are close to the
values determined in the Tingstad, Kaisermühlen and Chung-
Liao tunnels, but are well below those observed in the Lundby
and Marseille tunnels. The PM2.5 mean concentration obtained
in the Portuguese tunnel is within the values reported for
other road infrastructures. The contribution of EC to the PM2.5
mass is comparable to the value reported for the Mount