Trends in air pollutants and health impacts in three Swedish cities over the past three decades

Abstract

Abstract. Air pollution concentrations have been decreasing in many cities in the developed countries. We have estimated time trends and health effects associated with exposure to NOx, NO2, O3, and PM10 (particulate matter) in the Swedish cities Stockholm, Gothenburg, and Malmö from the 1990s to 2015. Trend analyses of concentrations have been performed by using the Mann–Kendall test and the Theil–Sen method. Measured concentrations are from central monitoring stations representing urban background levels, and they are assumed to indicate changes in long-term exposure to the population. However, corrections for population exposure have been performed for NOx, O3, and PM10 in Stockholm, and for NOx in Gothenburg. For NOx and PM10, the concentrations at the central monitoring stations are shown to overestimate exposure when compared to dispersion model calculations of spatially resolved, population-weighted exposure concentrations, while the reverse applies to O3. The trends are very different for the pollutants that are studied; NOx and NO2 have been decreasing in all cities, O3 exhibits an increasing trend in all cities, and for PM10, there is a slowly decreasing trend in Stockholm, a slowly increasing trend in Gothenburg, and no significant trend in Malmö. Trends associated with NOxand NO2 are mainly attributed to local emission reductions from traffic. Long-range transport and local emissions from road traffic (non-exhaust PM emissions) and residential wood combustion are the main sources of PM10. For O3, the trends are affected by long-range transport, and there is a net removal of O3 in the cities. The increasing trends are attributed to decreased net removal, as NOx emissions have been reduced. Health effects in terms of changes in life expectancy are calculated based on the trends in exposure to NOx, NO2, O3, and PM10 and the relative risks associated with exposure to these pollutants. The decreased levels of NOx are estimated to increase the life expectancy by up to 11 months for Stockholm and 12 months for Gothenburg. This corresponds to up to one-fifth of the total increase in life expectancy (54–70 months) in the cities during the period of 1990–2015. Since the increased concentrations in O3 have a relatively small impact on the changes in life expectancy, the overall net effect is increased life expectancies in the cities that have been studied.

Associations between Vehicle Exhaust Particles and Ozone at Home Address and Birth Weight

“…The mean exposure to PM-exhaust is reduced by nearly half from the beginning to the end of the study period. The trend in calculated PM-exhaust is verified by measured decreasing trends in NOx concentrations and increasing trends in ozone at an urban background monitoring site in Stockholm [7]. Full pregnancy exhaust particles levels ranged from 6.9 to 854 ng/m 3 with an average of 202 ng/m 3 , and ozone ranged from 28.8 to 66.7 µg/m 3 with an average of 54.6 µg/m 3 , as shown in Table 1.…”

“…There is an inverse correlation between ozone and PM exhaust due to the NO titration of ozone, as mentioned before. The inverse correlation is also verified by measurements of NOx, the total particle number, and ozone at an urban background site in central Stockholm[7].…”

“…The mixture of pollutants in ambient air is varying and complex, but vehicle exhaust particles and ozone typically show a negative correlation due to nitrogen oxide (NO) emissions reducing ozone levels when nitrogen dioxide (NO 2 ) is formed [7]. This negative correlation suggests that the effects from local levels of exhaust particles on ozone should be studied in multi-pollutant models to avoid confounding effects.…”

The impact of ship emissions on air quality and human health in the Gothenburg area – Part 1: 2012 emissions

“…The trends of SO 2 , NO x and NO 2 continuously decreased from 1990 to 2015 except for in the areas close to major roads (Miljöförvaltningen, 2017). O 3 exhibits an increasing trend, and there is also a slowly increasing trend for PM 10 in Gothenburg (Olstrup et al, 2018). The annual means for NO 2 , PM 10 and PM 2.5 (particulate matter with an aerodynamic diameter of less than or equal to 10 and 2.5 µm, respectively) during the period 2000-2017 are 12.5 ppb, 16.3 µg m −3 and 7.9 µg m −3 , respectively, at an urban background site in Gothenburg.…”

Health economic assessment of a scenario to promote bicycling as active transport in Stockholm, Sweden

“…Furthermore, it would not be meaningful to base predictions on possible future health trends for which there is a lack of reliable data. Such is the case regarding air pollution trends in Stockholm since 201046. Cost-effectiveness studies facing these and similar limitations have been published previously 47…”