The influence of season and living environment on children's urinary 1-hydroxypyrene levels in Ulaanbaatar, Mongolia

Background: Heating indoor living environments elevates air pollution in Ulaanbaatar, Mongolia. Objective: This study was conducted to investigate the influence of season and living environment on children's urinary 1-hydroxypyrene (1-OHP) levels in Ulaanbaatar, Mongolia. Methods: Our study subjects were 320 children aged 11-15 years living in gers, brick houses and apartments, in ger and non-ger areas of Ulaanbaatar. Spot urine samples and questionnaires were collected three times from each subject in three seasons, September (warm) and December (cold) in 2011 and March (moderate) in 2012. Urinary 1-OHP was analyzed by high-performance liquid chromatography with fluorescent detection (HPLC/FLD). Generalized estimating equation (GEE) models were applied to estimate the seasonal and residential effects on 1-OHP levels, adjusting for demographic and environmental factors. Results: Children's urinary 1-OHP levels showed significant seasonal differences with 0.30 +/- 0.57 mu mol/mol creatinine in cold season, 0.14 +/- 0.12 mu mol/mol creatinine in moderate season, and 0.14 +/- 0.21 mu mol/mol creatinine in warm season. After controlling confounding factors, the GEE model showed that season, living area, and housing type had significant influence on children's urinary 1-OHP levels. Urinary 1-OHP levels in the cold and moderate seasons were, respectively 2.13 and 1.37 times higher than the warm season. Urinary 1-OHP levels for children living in ger areas were 1.27 times higher than those living in non-ger areas. Children who lived in gers or brick houses had 1.58 and 1.34 times higher 1-OHP levels, respectively, compared with those living in apartments. Children's urinary 1-OHP levels were associated with either estimated NO2 or SO2 concentrations at their home addresses in Ulaanbaatar. Conclusion: Mongolian children's urinary 1-OHP levels were significantly elevated during the cold season, and for those living in ger areas, gers, or brick houses in Ulaanbaatar. Children's urinary 1-OHP levels were associated PAH co-pollutants SO2 and NO2, suggesting elevated 1-OHP levels may be attributable to PAH emissions from coal burning and traffic respectively, with indoor emissions from stoves further contributing to elevated 1-OHP in some children. (C) 2014 Elsevier Inc. All rights reserved.