we examined
whether changes that have occurred across these
time spans in levels of nitrogen dioxide, ozone,
and particulate matter with an aerodynamic diameter
of less than 2.5 μm (PM2.5), less than 10 μm
(PM10), and between 2.5 and 10 μm (coarse particulate
matter [PM10–PM2.5]) are associated with
the development of lung function in children.