
92 Environmental Health: Indoor Exposures, Assessments and Interventions
[15] studied PM
2.5
, PM
10
, benzene, and black smoke in 24 schools in the Netherlands
and found that PM
2.5
and black smoke increased with truck traffi c and decreased with
distance from highways (40, 000–170, 000 veh/d).
FIGURE 1 Ultrafine particle size distribution (top panel) and normalized particle number
concentration for different size ranges (bottom panel) as a function of distance from a highway
in Los Angeles. From Zhu et al. [8]. Reprinted with permission from Elsevier.