A recent study on the health impact of air pollution exposure in school children found that air pollution level along the travelling routes from home to schools and particulate level outside school are both very high. Also, most of the school children have weaker lung function than the predicted level. In this issue of Excel@PolyU, Dr Hung Wing-tat, Associate Professor of the Department of Civil and Environmental Engineering, shared with us the study findings.

How was the research conducted?
Researchers collected information on the travelling patterns of 310 school children from 12 schools and then monitored the air pollution level along their travelling routes. About 48% of school children go to school on foot while 24% of them take the school bus.

What were the research findings?
The research found that both PM₁₀ and PM_2.5 levels in various transportation modes are high. The PM_2.5 levels far exceed the stipulated health levels of World Health Organization safety level - 75 µg/m³ (24 hours average) and the situation was the worst in school buses. The volatile organic compound levels in all transportation modes far exceed the good class level of Hong Kong Indoor Air Quality (HKIAQ) and the situation was again the worst in school buses.

In addition, children in only two out of twelve surveyed schools have lung function better than predicted levels. The carbon dioxide levels inside the classrooms of five schools were found to be higher than the stipulated good class level of HKIAQ, probably due to the presence of full class of students and closed windows within the monitoring period.

What other causes contribute to the poor lung function of school children?
School children in tobacco smoking households have significantly poorer lung function. The study found high percentages of smokers in children’s households, ranging from 25.0% to 69.6%. Also, lung function indicators are found to be negatively co-related with PM₁₀ levels in classrooms. It is therefore critical to suppress the level of PM₁₀ in classrooms to protect the health of school children.

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