Ultrafine particulate air pollution and pediatric emergency-department visits for main respiratory diseases in Shanghai, China

Highlights: • UFP was associated with increased pediatric EDVs for main respiratory diseases. • The associations were independent from all criteria air pollutants. • The concentration-response relationship was almost linear. • Asthma may be most prominently affected by short-term exposure to UFP. • Children of 0–13 years may be more susceptible to UFP-induced respiratory diseases. Few studies have explored the short-term effects of ultrafine particles (UFPs, particles < 0.1 μm) air pollution on the exacerbations of pediatric respiratory diseases.