Self-reported traffic exposure is not strongly correlated modelled NOx in a Northern European cohort study

Abstract

Introduction: Few studies have investigated the association between self-reported and modelled exposure to traffic pollutants, the objective of this study was to examine the correlation between modelled NOx and self-reported traffic exposure in 7 different northern European cities. Methods: Data from the third wave of the RHINE (Respiratory Health in Northern Europe, rhine.nu) cohort with seven study centres in Denmark, Estonia, Iceland, Norway and Sweden in 2011 was analysed. Vehicle exhaust (NOx) was modelled using dispersion models and LUR. Some rural areas were excluded as they fell outside model coverage. Self-reported exposure was measured by the questions; “Is your bedroom window near a street (less than 20 m)” with replies in four categories from “No” to “Yes, with very much traffic” and “Can you hear traffic noise from your bedroom?” with replies from “No” to “A lot”. Data were analysed using rank correlation of quartiles of modelled NOx in each centre. Results: Data on variables of interest were available for 50% to 99% of the 3rd wave cohort participants. The presence or size of a street near the bedroom window correlated significantly with modelled NOx in all centres. Hearing traffic noise at the bedroom window correlated with modelled NOx in most centres. However, all correlations were moderate. Conclusions: Self-reported residential proximity to traffic exhaust and traffic noise have low or moderate correlations with modelled vehicle exhaust concentration level at the home address.