Personal exposure to particles in Banská Bystrica, Slovakia

Abstract

Epidemiological studies have associated adverse health impacts with ambient concentrations of particulate matter (PM), though these studies have been limited in their characterization of personal exposure to PM. An exposure study of healthy nonsmoking adults and children was conducted in Banska Bystrica, Slovakia, to characterize the range of personal exposures to air pollutants and to determine the influence of occupation, season, residence location, and outdoor and indoor concentrations on personal exposures. Twenty-four-hour personal, at-home indoor, and ambient measurements of PM₁₀, PM_2.5, sulfate (SO₄²⁻) and nicotine were obtained for 18 office workers, 16 industrial workers, and 15 high school students in winter and summer. Results showed that outdoor levels of pollutants were modest, with clear seasonal differences: outdoor PM₁₀ summer/winter mean=35/45 µg/m³; PM_2.5 summer/winter mean=22/32 µg/m³. SO₄²⁻ levels were low (4–7 µg/m³) and relatively uniform across the different sample types (personal, indoor, outdoor), areas, and occupational groups. This suggests that SO₄²⁻ may be a useful marker for combustion mode particles of ambient origin, although the relationship between personal exposures and ambient SO₄²⁻ levels was more complex than observed in North American settings. During winter especially, the central city area showed higher concentrations than the suburban location for outdoor, personal, and indoor measures of PM₁₀, PM_2.5, and to a lesser extent for SO₄²⁻, suggesting the importance of local sources. For PM_2.5 and PM₁₀, ratios consistent with expectations were found among exposure indices for all three subject groups (personal>indoor>outdoor), and between work type (industrial>students>office workers). The ratio of PM_2.5 personal to indoor exposures ranged from 1.0 to 3.9 and of personal to outdoor exposures from 1.6 to 4.2. The ratio of PM₁₀ personal to indoor exposures ranged from 1.1 to 2.9 and the ratio of personal to outdoor exposures from 2.1 to 4.1. For a combined group of office workers and students, personal PM₁₀/PM_2.5 levels were predicted by statistically significant multivariate models incorporating indoor (for PM_2.5) or outdoor (for PM₁₀) PM levels, and nicotine exposure (for PM₁₀). Small but significant fractions of the overall variability, 15% for PM_2.5 and 17% for PM₁₀, were explained by these models. The results indicate that central site monitors underpredict actual human exposures to PM_2.5 and PM₁₀. Personal exposure to SO₄²⁻ was found to be predicted by outdoor or indoor SO₄²⁻ levels with 23–71% of the overall variability explained by these predictors. We conclude that personal exposure measurements and additional demographic and daily activity data are crucial for accurate evaluation of exposure to particles in this setting.