e 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 responses in the lungs.
The aim of this study was to examine the health effects of ambient particulate air pollution (largely derived from wood-burning for home heating) on school-age children in a panel study design, and to explore the utility of urine and exhaled breath condensate biomarkers of exposure in this population. To reduce exposure variation, and provide accurate assessment of exposure, school children from the boarding houses of a metropolitan private school were studied. Longitudinal studies of lung function effects were undertaken using personal electronic spirometers and symptom diaries, and, after high pollution events, detailed event studies of pollution effects were undertaken using exhaled breath condensate and urine collection.
The study was undertaken in winter 2004 in Christchurch, New Zealand, a city of ~330,000 situated on the east coast of the South Island. Significant air pollution in Christchurch almost invariably occurs in winter, and is characterized by PM10, ~90% of which is PM2.5, that is largely generated by domestic wood-burning open fires and enclosed wood-burners . Mean daily PM10 in central and suburban Christchurch exceeds 50 μg/m3 on ~30 days per year and can reach up to 250 μg/m3 . The health effects of Christchurch air pollution have been the subject of a number of local studies [9–11].
The study was undertaken in the boarding houses at Christ's College, a single-sex private school situated in the central city, but inset into the grounds of Hagley Park, a five km2 area of grassland and trees to the immediate west of the CBD but surrounded by the urban area on all sides.
Two pollution monitoring sites were established for this project. The indoor site was a second floor corridor leading to rooms occupied by boarding students. The building is naturally ventilated and is heated by a thermostatically controlled central heating system. The site was not near any obvious indoor sources of particulates such as kitchens which are located in a different building. The outdoor site was