Personal exposure of children to formaldehyde in Perth, Western Australia

Formaldehyde is a common air pollutant that tends to be found in elevated concentrations in indoor air. Exposure to formaldehyde has the potential to impact on respiratory health, particularly amongst sensitive individuals and populations, including children. Children spend most of their time indoors at home, however, there are very little data on the contribution of formaldehyde concentrations in homes to personal exposure in children. The principal aim of this cross sectional study was to investigate whether the domestic environment is the most significant source of personal exposure of formaldehyde in children. Forty-one primary school children (aged between 8 and 12) were recruited from two areas of Perth, Western Australia. Each child wore a personal passive formaldehyde sampler over a 24 hour period on two separate occasions, winter and summer. Samplers were also located indoors at home, outdoors at centralised locations and indoors at school for the corresponding period. A questionnaire about lifestyle and behaviour and a daily activity diary were completed for each participant. Passive samplers used filter papers impregnated with 2,4-dinitrophenylhadrazine (DNPH), with formaldehyde detected using high pressure liquid chromatography (HPLC). In winter there was a wide range of personal exposure concentrations, with geometric mean concentrations of 9.7ppb at Duncraig and 11.5ppb at Calista. Indoor geometric mean concentrations at Duncraig were l0.lppb, with outdoor and classroom concentrations below the analytical limit of detection (4ppb). At Calista, mean indoor concentrations were 14.2ppb. The outdoor concentrations were below the limit of detection and school concentrations were 8.0ppb. Summer monitoring occurred during mild meteorological conditions and were very similar to winter results. Geometric mean personal exposure concentrations were 9.2ppb at Duncraig and 8.0ppb at Calista. Indoor geometric mean concentrations at Duncraig were 9.0ppb, with outdoor and classroom concentrations below the limit of detection (4ppb). At Calista, mean indoor concentrations were 9.9ppb, outdoor was below detection limit and school concentrations were l5.2ppb. There were strong correlations between personal exposure and domestic concentrations at both Duncraig and Calista in winter (r2 = 0.73 and 0.88, respectively) and in summer (r2 = 0.67 and 0.84, respectively). The correlation for both seasons combined was significant, with a coefficient of r2 = 0. 78. A time weighted model estimated personal exposure concentrations for each participant using stationary measures in combination with time activity data. These estimates of exposure correlated significantly with measured personal exposure concentrations, with a coefficient of r2 = 0.80 for all data combined. The indoor domestic environment was found to be the most important source of formaldehyde exposure for children. Time weighting was found to provide a stronger estimate of personal exposure than indoor air monitoring alone, although the time weighted model was not a significant improvement over the indoor measure alone