Objectives: This study assessed personal exposure of pregnant women to fine particles (PM(25)) and benzo[a]pyrene (B[a]P) and the relationship between pollutant concentrations in ambient and indoor air.
Materials and methods: In a group of 78 pregnant women, simultaneous 48 h measurements of personal, indoor, and outdoor exposure to PM(25) and B[a]P were carried out in the second trimester of pregnancy. The results show that participants were exposed to varying concentrations of PM(25) and B[a]P, with higher exposure in the winter season. Overall, the mean personal PM(25) level was 30.4 microg/m(3) and B[a]P 2.1 ng/m(3). The winter/summer ratios for mean personal exposures were 1.4 (35.6 microg/m(3) vs. 25.8 microg/m(3)) and 5.4 (4.9 ng/m(3) vs. 0.9 ng/m(3)), respectively. As for indoor levels, the winter/summer ratios were 1.4 (33.2 microg/m(3) vs. 24.4 microg/m(3)) for PM(25) and 5.4 (4.3 ng/m(3) vs. 0.8 ng/m(3)) for B[a]P, and for outdoor concentrations, the respective values were 1.5 (40.3 microg/m(3) vs. 26.4 microg/m(3), and 6.8 (6.1 ng/m(3) vs 0.9 ng/m(3)). A stronger correlation was found between personal PM(25) exposure and the pollutant concentration indoors (r = 0.89; 95% CI: 0.83-0.93) than outdoors (r = 0.75; 95% CI: 0.64-0.83). The correlations between personal B[a]P exposure and its indoor or outdoor levels were similar (0.95-0.96) and significant. The markedly higher exposure to B[a]P in Kraków in winter than in summer can be explained by the massive use of coal for heating in the cold season.
Conclusion: We conclude that although ambient PM(25) measurements provide an adequate indicator of outdoor air quality for use in epidemiologic studies, they may not be adequate for studies on relationship between non-ambient pollution and health effects. Since only about 20% of variability in personal B[a]P exposure could be explained by personal PM(25) level, the extrapolation of personal exposure to B[a]P from personal PM(25) data may be greatly underestimated.