Using a discrete choice experiment this study examines whether different types of priming may influence the respondents’ answers when choosing between different policies aimed at reducing the mortality risk due to ambient air pollution. We focus on two types of priming: (i) two versions of an oath where respondents commit to answer truthfully during the survey, and (ii) a priming scenario that combines information about the social cost of ambient air pollution and questions on the respondents’ experiences related to the topic. To test the robustness of the findings the same survey is implemented in two different countries, the United States (US) and the United Kingdom (UK). Results show that respondents behave as expected in the choice situations and the two estimates of the value of statistical life (VSL) obtained are in line with values recommended for policy purposes in both countries. Regarding the priming treatments, we find that the oath treatments have different effects in the US and in the UK, and that the priming scenario has an effect on those who have already been suffering from air pollution (US), or on those who are willing to change and undertake actions to protect the environment (UK).