Seasonal Variations in the Daily Mortality Associated with Exposure to Particles, Nitrogen Dioxide, and Ozone in Stockholm, Sweden, from 2000 to 2016

Henrik Olstrup,Bertil Forsberg,Christer Johansson,Christofer Åström,Hans Orru

doi:10.3390/atmos12111481

Henrik Olstrup, Bertil Forsberg + Show 3 more

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https://doi.org/10.3390/atmos12111481

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Abstract

Urban air pollutant emissions and concentrations vary throughout the year due to various factors, e.g., meteorological conditions and human activities. In this study, seasonal variations in daily mortality associated with increases in the concentrations of PM10 (particulate matter), PM2.5–10 (coarse particles), BC (black carbon), NO2 (nitrogen dioxide), and O3 (ozone) were calculated for Stockholm during the period from 2000 to 2016. The excess risks in daily mortality are presented in single and multi-pollutant models during the whole year and divided into four different seasons, i.e., winter (December–February), spring (March–May), summer (June–August), and autumn (September–November). The excess risks in the single-pollutant models associated with an interquartile range (IQR) increase for a lag 02 during the whole year were 0.8% (95% CI: 0.1–1.4) for PM10, 1.1% (95% CI: 0.4–1.8) for PM2.5–10, 0.5% (95% CI: −0.5–1.5) for BC, −1.5% (95% CI: −0.5–−2.5) for NO2, and 1.9% (95% CI: 1.0–2.9) for O3. When divided into different seasons, the excess risks for PM10 and PM2.5–10 showed a clear pattern, with the strongest associations during spring and autumn, but with weaker associations during summer and winter, indicating increased risks associated with road dust particles during these seasons. For BC, which represents combustion-generated particles, the pattern was not very clear, but the strongest positive excess risks were found during autumn. The excess risks for NO2 were negative during all seasons, and in several cases even statistically significantly negative, indicating that NO2 in itself was not harmful at the concentrations prevailing during the measurement period (mean values < 20 µg m−3). For O3, the excess risks were statistically significantly positive during “all year” in both the single and the multi-pollutant models. The excess risks for O3 in the single-pollutant models were also statistically significantly positive during all seasons.

Highlights

While air pollutant emissions occur throughout the whole year, differences in meteorological conditions and human activities cause large seasonal variations in most pollutants
The main objective of this study was to analyze seasonal variations in the excess risks for daily mortality associated with an interquartile range increase in PM10, PM2.5–10, black carbon (BC), NO2, and O3 in Stockholm during the period from 2000 to 2016
The current study showed a broadly similar pattern for excess risks associated with PM2.5–10 and PM10 with larger risk increases in daily mortality during springtime

Summary

Introduction

While air pollutant emissions occur throughout the whole year, differences in meteorological conditions and human activities cause large seasonal variations in most pollutants. In a study from the Netherlands, the associations between daily mortality and short-term variations in a number of air pollutants were analyzed during the period from 1986 to 1994, and the results were, among other things, divided into summer and winter seasons [4]. They found significantly (95% CI) increased relative risks for all pollutants (PM10, BS (black smoke), O3, SO2, NO2, CO, SO4−2, and NO3−) during both summer and winter, except for O3 and SO4−2 during the winter. The relative risks for total mortality associated with exposure to these air pollutants were in all cases larger during the summer compared to the winter [4]

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