Objective: To determine the acute effects of exposure to fine particulate matter(PM_(2. 5))on children's respiratory inflammation and oxidative stress.
Methods: This study was a cross-sectional study. A total of 115 9-12 year-old children in boarding schools were selected as the research objects. The PM_(2. 5) exposure concentration was continuously monitored for 5 days, and the individual exposure level was estimated by using the time activity mode and the PM_(2. 5) microenvironment concentration. Exhaled breath condensate(EBC) and urine samples were collected on the 5 th day. Fractional exhaled nitric oxide(FeNO) was detected by a FeNO detector, EBC pH was measured by microelectrode potential analysis method, urine 8-hydroxydeoxyguanosine(8-OHdG) was detected by ELISA kit, and the effect of PM_(2. 5) on three effect indicators was analyzed by a linear model.
Results: The highest individual exposure concentration was 102 μg/m~3 4 days before the physical examination, and the lowest individual exposure concentration was 9. 19 μg/m~3 2 days before the physical examination. The FeNO of boys was higher than that of girls, and the difference was significant(P<0. 05). There were no significant differences between gender in other indicators. Correlation analysis found that there was a significant correlation between the exposure concentration of PM_(2. 5) and FeNO, and the strongest correlation was 0 to 2 days before the physical examination with each 10 μg/m~3 increase in PM_(2. 5) caused a 29. 7% increase in FeNO, other indicators did not change significantly. Gender subgroup analysis found that PM_(2. 5) had a significant effect on boys' FeNO, every 10 μg/m~3 increase in PM_(2. 5) during the study period can cause an increase in boys' FeNO of 3. 47%-50. 97%, but had no significant effect on all three indicators of girls.
Conclusion: PM_(2. 5) had significant effects on FeNO in healthy children with immediate and delayed effects, especially on boys.
Keywords: 8-hydroxydeoxyguanosine; air polution; child health; fine particulate matter; fractional exhaled nitric oxide; pH.