Exposure to ambient ultrafine particles and urinary 8-hydroxyl-2-deoxyguanosine in children with and without eczema

• Ambient ultrafine particles were associated with oxidative stress in children.
• Particles sized 47 nm was most strongly associated with increase in urinary 8-OHdG.
• Immediate effect of particle on oxidative stress was observed in children with eczema.
• The effect of mass fraction particle on oxidative stress in children was less clear.

Ambient fine and ultrafine particles (UFPs) in urban air are known to contribute to inflammatory and allergic disease. It has been suggested that oxidative stress is an underlying mechanism for the detrimental health effects. The objective of this study was to investigate the short-term effect of ambient UFPs and particulate polycyclic aromatic hydrocarbons (PAHs) on urinary 8-hydroxyl-2-deoxyguanosine (8-OHdG) concentrations in children with and without eczema. Spot urine samples were collected from 84 children twice weekly for 61 days and 8-OHdG content was measured. Significant associations were found between the ambient UFPs and particle bound PAHs and increase in urinary 8-OHdG levels. An inter-quartile range (IQR) increase in the UFP concentration in the 24-h (IQR, 32,300/m3) period preceding urine collection was significantly associated with a 5.7% (95% confidence interval [CI], 0.16–1.27%) increase in the urinary 8-OHdG level children with AD. In children without eczema, such short-term effect of previous day UFPs on urinary 8-OHdG was not observed. There were no significant positive associations between the mass fraction of PMs and urinary 8-OHdG. The results suggest that short-term exposure to ambient UFPs plays a critical role in PM induced oxidative stress in children with eczema.