Personal exposure levels to O3, NOx and PM10 and the association to ambient levels in two Swedish cities

Susanna Lohman Haga; Annika Hagenbjörk; Anna-Carin Olin; Bertil Forsberg; Ingrid Liljelind; Hanne Krage Carlsen; Lars Modig

doi:10.1007/s10661-021-09447-7

Personal exposure levels to O₃, NO_x and PM₁₀ and the association to ambient levels in two Swedish cities

Environ Monit Assess. 2021 Sep 27;193(10):674. doi: 10.1007/s10661-021-09447-7.

Authors

Susanna Lohman Haga¹, Annika Hagenbjörk², Anna-Carin Olin³, Bertil Forsberg², Ingrid Liljelind², Hanne Krage Carlsen³, Lars Modig²

Affiliations

¹ Occupational and Environmental Medicine, School of Public Health and Community Medicine, Sahlgrenska Academy At University of Gothenburg, Gothenburg, Sweden. susanna@lohman-haga.com.
² Department of Public Health and Clinical Medicine, Section for Sustainable Health At Umeå University, Umeå, Sweden.
³ Occupational and Environmental Medicine, School of Public Health and Community Medicine, Sahlgrenska Academy At University of Gothenburg, Gothenburg, Sweden.

Abstract

Exposure to air pollution is of great concern for public health although studies on the associations between exposure estimates and personal exposure are limited and somewhat inconsistent. The aim of this study was to quantify the associations between personal nitrogen oxides (NO_x), ozone (O₃) and particulate matter (PM₁₀) exposure levels and ambient levels, and the impact of climate and time spent outdoors in two cities in Sweden. Subjects (n = 65) from two Swedish cities participated in the study. The study protocol included personal exposure measurements at three occasions, or waves. Personal exposure measurements were performed for NO_x and O₃ for 24 h and PM₁₀ for 24 h, and the participants kept an activity diary. Stationary monitoring stations provided hourly data of NO_x, O₃ and PM, as well as data on air temperature and relative humidity. Data were analysed using mixed linear models with the subject-id as a random effect and stationary exposure and covariates as fixed effects. Personal exposure levels of NO_x, O₃ and PM₁₀ were significantly associated with levels measured at air pollution monitoring stations. The associations persisted after adjusting for temperature, relative humidity, city and wave, but the modelled estimates were slightly attenuated from 2.4% (95% CI 1.8-2.9) to 2.0% (0.97-2.94%) for NO_x, from 3.7% (95% CI 3.1-4.4) to 2.1% (95% CI 1.1-2.9%) for O₃ and from 2.6% (95% 0.9-4.2%) to 1.3% (95% CI - 1.5-4.0) for PM₁₀. After adding covariates, the degree of explanation offered by the model (coefficient of determination, or R²) did not change for NO_x (0.64 to 0.63) but increased from 0.46 to 0.63 for O₃, and from 0.38 to 0.43 for PM₁₀. Personal exposure to NO_x, O₃ and PM has moderate to good association with levels measured at urban background sites. The results indicate that stationary measurements are valid as measure of exposure in environmental health risk assessments, especially if they can be refined using activity diaries and meteorological data. Approximately 50-70% of the variation of the personal exposure was explained by the stationary measurement, implying occurrence of misclassification in studies using more crude exposure metrics, potentially leading to underestimates of the effects of exposure to ambient air pollution.

Keywords: Air pollution; NOx; O3; PM10; Personal exposure.

MeSH terms

Air Pollutants* / analysis
Air Pollution* / analysis
Cities
Environmental Monitoring
Humans
Sweden

Substances

Air Pollutants