Air pollution as a risk factor in health impact assessments of a travel mode shift towards cycling

Abstract

Background: Promotion of active commuting provides substantial health and environmental benefits by influencing air pollution, physical activity, accidents, and noise. However, studies evaluating intervention and policies on a mode shift from motorized transport to cycling have estimated health impacts with varying validity and precision. Objective: To review and discuss the estimation of air pollution exposure and its impacts in health impact assessment studies of a shift in transport from cars to bicycles in order to guide future assessments. Methods: A systematic database search of PubMed was done primarily for articles published from January 2000 to May 2016 according to PRISMA guidelines. Results: We identified 18 studies of health impact assessment of change in transport mode. Most studies investigated future hypothetical scenarios of increased cycling. The impact on the general population was estimated using a comparative risk assessment approach in the majority of these studies, whereas some used previously published cost estimates. Air pollution exposure during cycling was estimated based on the ventilation rate, the pollutant concentration, and the trip duration. Most studies employed exposure-response functions from studies comparing background levels of fine particles between cities to estimate the health impacts of local traffic emissions. The effect of air pollution associated with increased cycling contributed small health benefits for the general population, and also only slightly increased risks associated with fine particle exposure among those who shifted to cycling. However, studies calculating health impacts based on exposure-response functions for ozone, black carbon or nitrogen oxides found larger effects attributed to changes in air pollution exposure. Conclusion: A large discrepancy between studies was observed due to different health impact assessment approaches, different assumptions for calculation of inhaled dose and different selection of dose-response functions. This kind of assessments would improve from more holistic approaches using more specific exposure-response functions.

Modelling of the public health costs of fine particulate matter and results for Finland in 2015

“…American Cancer Society published an estimate of 1.075 that was used in Heo et al (2016). A more conservative estimate of 1.06 has been reported in some studies such as Defra et al (2015 andRaza et al (2018), apart from Woodcock et al (2009;2014) and Dhondt et al (2013). The…”

“…This value has also been used widely (Fann et al 2009;Levy et al 2009). Raza et al (2018) presented an even higher RR for PM2.5 (RR=1.17) in their paper which was originally reported in another study regarding air pollution and mortality in Los Angeles (Jerrett et al, 2005) 130 Next step in the analysis chain is to convert the health impacts into monetary values. With respect to mortality, there are two main approaches for the monetary valuation: either (i) counting the expected value of life years lost and multiplying with the value of a life year (VOLY), or (ii) counting the expected value of early mortality and multiplying with the value of life (VSL).…”

“…The exposure to fine particulate matter has been reported to be associated with a substantial number of health outcomes in epidemiological studies (Qi et al, 2018;Raza et al, 2018;Im et al, 2018); however, reliable estimates of the concentration-response functions have been derived only for a limited number of outcomes. In this study, the functions recommended within the HRAPIE project were used (WHO, 2013b).…”

“…The cost of a hospital admission is partly based on the willingness to pay approach (WTP), as estimated by Ready et al (2004). The WTP estimate takes into account three days in hospital care (because of a respiratory disease), and five days of bed rest at home.…”

“…We adjusted the unit costs for inflation, but not for the changes in the income levels, which is 450 accordance with the practice in the previous EU-wide assessment by Holland (2014). The WTP values were selected according to Ready et al (2004), in which the results have been reported in pounds in 1998. In this study, these have been converted to euros using the purchasing power parity index, and to the values in 2017 using the Harmonised Index of Consumer Prices.…”