Volumes 497–498, 1 November 2014, Pages 420–429 •WTP to avoid air pollution and noise effects substantially varied by country.•Risk perceptions and environmental concerns affected WTP estimates.•Perception and concern differences affected between-country differences in WTP.•Air pollution WTP is higher than for noise if only qualitative information is given.•WTP to avoid severe annoyance was higher than for 1/2 year change in life expectancy.We conducted a multi-country study to estimate the perceived economic values of traffic-related air pollution and noise health risks within the framework of a large European project. We used contingent valuation as a method to assess the willingness-to-pay (WTP) for both types of pollutants simultaneously. We asked respondents how much they would be willing to pay annually to avoid certain health risks from specific pollutants. Three sets of vignettes with different levels of information were provided prior to the WTP questions. These vignettes described qualitative general health risks, a quantitative single health risk related to a pollutant, and a quantitative scenario of combined health risks related to a pollutant.

The mean WTP estimates to avoid road-traffic air pollution effects for the three vignettes were: €130 per person per year (pp/y) for general health risks, €80 pp/y for a half year shorter in life expectancy, and €330 pp/y to a 50% decrease in road-traffic air pollution. Their medians were €40 pp/y, €10 pp/y and €50 pp/y, respectively. The mean WTP estimates to avoid road-traffic noise effects for the three vignettes were: €90 pp/y for general health risks, €100 pp/y for a 13% increase in severe annoyance, and €320 pp/y for a combined-risk scenario related to an increase of a noise level from 50 dB to 65 dB. Their medians were €20 pp/y, €20 pp/y and €50 pp/y, respectively. Risk perceptions and attitudes as well as environmental and pollutant concerns significantly affected WTP estimates. The observed differences in crude WTP estimates between countries changed considerably when perception-related variables were included in the WTP regression models. For this reason, great care should be taken when performing benefit transfer from studies in one country to another.

The health risks of traffic-related air pollution (e.g., increased risks of heart attacks, the exacerbation of asthma among children, and reductions in life expectancy/LE) and noise (e.g., noise annoyance, sleep disturbance, hypertension, cardiovascular risks, and poorer school performance) have been extensively documented by a numerous epidemiological studies (Brunekreef and Holgate, 2002, Hoek et al., 2002, World Health Organization, W. H. O., 2012, World Health Organization, W. H. O., 2013 and Basner et al., 2014). These health and wellbeing risks generate substantial costs for society (El-Fadel and Massoud, 2000, Kan and Chen, 2004, Zhang et al., 2007 and Pascal et al., 2013) that are external to a large extent because they are not reflected in the market price of transportation or accounted for in the allocation of economic resources (Levy et al., 2010). It is increasingly recognised by the European Ministerial Conferences on Environment and Health and WHO that in order to effectively and efficiently manage environmental quality, it is necessary to take into account all costs and benefits of alternative policy scenarios for use in rational planning procedures (Randall, 1986) and to develop ways to make them more transparent (World Health Organization, 2000).

The assessment of willingness-to-pay (WTP) is a common approach to valuate individual preferences and the prices of non-market goods such as environmental quality (Hoevenagel, 1994 and U.S. Environmental Protection Agency, 2011).air duct cleaning gardenaEconomic values of road-traffic-related air pollution and noise are often assessed using different instruments. lucky bamboo air purifierThe risks of air pollution are predominantly evaluated in terms of stated willingness-to-pay/WTP using contingent valuation (CV) approaches, whereas many noise studies assess revealed WTP, using hedonic price approaches (Navrud et al., 2006 and Desaigues et al., 2011). guardian uv air purifierThe differences in the WTP estimation methodologies applied to air pollution and noise hamper the joint use and comparison of outcome data, particularly because the risks of these pollutants differ in nature and severity.

Therefore, we simultaneously assessed the WTP for the risks of traffic-related air pollution and noise on health using one instrument and approach. We conducted this assessment within the EU-funded project, “Integrated Assessment of Health Risks from Environmental Stressors in Europe” (Briggs, 2008 and Integrated Assessment of Health Risks of Environmental Stressors in Europe (INTARESE), 2009; Integrated Assessment of Health Risks of Environmental Stressors in Europe (INTARESE), 2012).Our research questions were: i) How much are people willing to pay to avoid health risks from road-traffic-related air pollution and noise? ii) Which determinants were associated with the WTP for these health risks? and iii) What are the differences in WTP values across countries?The determinants of interest were i) demographic and socioeconomic factors including those cited in the economics literature such as household income, gender and education (Thompson, 1986, Robinson, 1993, O'Brien and Viramontes, 1994, Blumenschein and Johannesson, 1998, Diener et al., 1998, Ready et al., 2004 and Van Doorslaer et al., 2006);

ii) factors identified in the public health literature, i.e. the severity of health risks, familiarity with the risks, and current health status (Fischer et al., 1991, Blumenschein and Johannesson, 1998, Van Doorslaer et al., 2006 and Lloyd et al., 2008); and iii) factors identified in the social sciences literature (i.e. aspect of risk perception, such as familiarity and level of awareness of the risks, level of concern regarding environmental health risks, and perceived level of exposure) which are based on respondents point of view and are, therefore, subjective in nature. This latter set of determinants is not typically included in WTP studies of environmental health risks; however, these factors are considered important in the social sciences for obtaining value preferences (Fischhoff and Furby, 1988, Johnson and Slovic, 1995 and El-Fadel and Massoud, 2000). Therefore, we considered them to be of potential interest given their relationships to the perception and acceptability of risks.

We drafted four hypotheses based on the (social sciences) literature, to guide our statistical analyses:-People who are well aware of the health effects of road-traffic air pollution and noise have a higher WTP.-People who report to be very concerned about the environment in general, and/or very concerned about the effects of air pollution and/or noise specifically, have higher WTP.-People who report to be very annoyed by road-traffic air pollution or noise provide higher WTP.-People who report to be highly sensitive towards the effects of air pollution and/or noise, and/or have difficulty relaxing in polluted or noisy places, provide higher WTP.A web-based questionnaire survey was carried out in December 2010 in the United Kingdom (UK), Finland (FI), Germany (GE), the Netherlands (NL) and Spain (SP).An external survey agency (Blauw Research, ISO9001&ISO20252 certified) recruited respondents through their existing population panels in the five countries. Panellists were invited to participate through the regular panel procedures (e-mail) and received a personal login code and password to fill in the web-based questionnaire.

By weighting on age, sex and education, the sampling was representative for the population of the specified countries, aged 18 to 64 years old. We aimed at 2000 respondents per country.The questionnaire consisted of the three main groups of questions, reflecting our determinants of interest. These are: i) demographical and social–economic factors, recognised in the economics literature and others, i.e. household income, gender, education, ii) factors from the public health domain i.e. familiarity with the (severe) health effects, current health status, and iii) factors from the social sciences domain, i.e. familiarity, attitude and perception of risks, level of awareness, level of concern of environmental health effects, perceived level of exposure. Where possible, we followed widely applied and standardised questions and scales. We made two versions of the questionnaire to limit size and cognitive burden to the respondents; one version is focusing on road traffic-related air pollution and the other on road traffic-related noise.