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The effect of ambient air pollution on respiratory health of school children: a panel study
Environmental Health volume 7, Article number: 16 (2008)
Adverse respiratory effects of particulate air pollution have been identified by epidemiological studies. We aimed to examine the health effects of ambient particulate air pollution from wood burning on school-age students in Christchurch, New Zealand, and to explore the utility of urine and exhaled breath condensate biomarkers of exposure in this population.
A panel study of 93 male students (26 with asthma) living in the boarding house of a metropolitan school was undertaken in the winter of 2004. Indoor and outdoor pollution data was continuously monitored. Longitudinal assessment of lung function (FEV1 and peak flow) and symptoms were undertaken, with event studies of high pollution on biomarkers of exposure (urinary 1-hydroxypyrene) and effect (exhaled breath condensate (EBC) pH and hydrogen peroxide concentration).
Peak levels of air pollution were associated with small but statistically significant effects on lung function in the asthmatic students, but not healthy students. No significant effect of pollution could be seen either on airway inflammation and oxidative stress either in healthy students or students with asthma. Minor increases in respiratory symptoms were associated with high pollution exposure. Urinary 1-hydroxypyrene levels were raised in association with pollution events by comparison with low pollution control days.
There is no significant effect of ambient wood-smoke particulate air pollution on lung function of healthy school-aged students, but a small effect on respiratory symptoms. Asthmatic students show small effects of peak pollution levels on lung function. Urinary 1-hydroxypyrene shows potential as a biomarker of exposure to wood smoke in this population; however measurement of EBC pH and hydrogen peroxide appears not to be useful for assessment of population health effects of air pollution.
Some of the data presented in this paper has previously been published in Kingham and co-workers Atmospheric Environment, 2006 Jan; 40: 338–347 (details of pollution exposure), and Cavanagh and co-workers Sci Total Environ. 2007 Mar 1;374(1):51-9 (urine hydroxypyrene data).
Epidemiological studies have established the adverse health effects of particulate air pollution, particularly in relation to cardiac and respiratory effects [1, 2]. However, direct assessment of health impacts of air pollution on individuals presents significant challenges, including the difficulty and expense of accurately assessing personal exposures [3, 4], variation in exposure in home versus school/work and outdoor versus indoor environments and exposure to tobacco smoke. The source of the particulate pollution may also be relevant. The majority of research from the USA and Europe has studied particulate pollution from coal-fired power stations, heavy industry, and diesel engines. However, wood and other organic matter combustion may be significant source of exposure in areas burning solid fuel for domestic heating, such as Canada and the North West USA, Scandinavia, and New Zealand. Indeed there is an increasing trend for wood to be used as a source of home heating in the New England states and in upstate New York.
Direct assessment of lung effects has generally been limited to measurement of peak expiratory flow rate (PEFR) diaries, which, like any self-administered test involving writing down numerical values, may be prone to subjective bias, end-digit preference and auto-correlation. More recently, the availability of electronic downloadable spirometers means detailed lung function assessment in large cohorts can be undertaken easily and cheaply. The spirometers incorporate quality assessment protocols and provide a more objective assessment of lung function. In addition, techniques such as exhaled breath condensate collection now allow non-invasive assessment of airway inflammation, and potentially provide information about oxidative stress r