The health outcomes due to ambient air pollution include
mortality, chronic morbidity, hospital admissions and outpatients,
and decline in lung function. Compared with adults, children are
more vulnerable to particulates and gaseous pollutants in the air
because of their immature immune systems. Moreover, children
have differential abilities to metabolize and detoxify environmental
agents and have an airway epithelium that is more permeable to
inhaled air pollutants (Schwartz, 2004). Daily hospital admission
counts of children with respiratory diseases from the pediatric
department of Shanghai Sixth People’s Hospital and Children’s
Hospital of Fudan University were collected. The causes of hospital
admission were coded according to International Classification of
Diseases, Revision 10 (ICD–10)