The authors used a longitudinal observational design, with repeated measure
s, to study the association between traffic-related air pollutants (i.e., n
itric oxide, nitrogen dioxide, carbon monoxide, and Black Smoke) and respir
atory symptoms. Subjects (N = 82) attended an elementary school in either U
trecht (i.e., urban children) or Bilthoven (i.e., suburban children). These
two geographic areas differed with respect to levels of Black Smoke (means
= 53 mug/m(3) and 18 mug/m(3), respectively). Levels of nitric oxide, nitr
ogen dioxide, carbon monoxide, and Black Smoke were consistently higher in
Utrecht than in Bilthoven (mean daily ratios were 8, 1.5, 1.8, and 2.7, res
pectively). The authors compared mean levels of short-term effects of the a
forementioned air pollutants on suburban and urban children. Urban children
had higher mean levels (p = .05) of interleukin-8 (32%), urea (39%), uric
acid (26%), albumin (15%), and nitric oxide metabolites (21%) in nasal lava
ge than did suburban children. Peak expiratory flow, exhaled nitric oxide l
evels, and nasal markers were associated with levels of particulate matter
with diameters less than or equal to 10 mum, Black Smoke, nitrogen dioxide,
and nitric oxide. With respect to per-unit increases in air pollution, urb
an children had more increased peak expiratory flow higher levels of exhale
d nitric oxide, and more increased release of uric acid, urea, and nitric o
xide metabolites than suburban children. In summary, urban children had inc
reased levels of inflammatory nasal markers, and their responses were more
pronounced than were the suburban children's responses to the same incremen
ts of air pollution.