Health impacts of active commuters’ exposure to traffic-related air pollution in Stockholm, Sweden

Abstract

IntroductionAddressing walking and cycling commuters, this study aimed to measure personal exposure to traffic-related air pollution and analyze the associated health risks. MethodDiffusive NO2-samplers were worn by 19 participants as they commuted to work in rush-hour traffic in May 2018 in Stockholm, Sweden (in total 336 trips, 197 h). The average NO2-concentration per route was measured, and the health impacts were calculated based on previous epidemiological studies of the association between annual NO2-exposure and premature death. ResultThe measured average concentration per route ranged from 48 to 105 μgNO2/m3, and the average 67 μgNO2/m3 was more than five times higher than the urban background. This corresponded to an annual mean exposure of 16.4 μgNO2/m3, 40% higher than the average exposure at other times. Thus, the increased risk for premature death was 3.3%, with a range of 1.9%–4.8%, as related to assumptions regarding breathing rates and risk relationships between NO2-exposure and premature death. For active commuters in Stockholm in general, this indicated that one-fourth (23%) of the annual inhaled dose of NO2 could be attributed to commuting, and that the risk for premature death increased by 2.5% (1.4%–3.7%) due to air pollution. Note that these results were indicative rather than precise. These relationships may be applicable to active commuters in other cities. ConclusionThe results indicated that active commuting in Stockholm is associated with significant exposure to traffic-related air pollution and that this increases the risk of premature death. It is recommended that future studies consider longer time periods to assess active commuters’ personal exposure with higher precision. Policy implications include greater separation between active commuters and motor traffic, and promotion of behavioral changes in favor of emissions free vehicles and active modes of transport.