Objectives Few studies have assessed the effects of policies aimed to reduce traffic-related air pollution. The aims of this study were to evaluate the impact, in terms of air quality and health effects, of two low-emission zones established in Rome in the period 2001–2005 and to assess the impact by socioeconomic position (SEP) of the population.

Methods We evaluated the effects of the intervention on various stages in the full-chain model, that is, pressure (number and age distribution of cars), emissions, PM₁₀ and NO₂ concentrations, population exposure and years of life gained (YLG). The impact was evaluated according to a small-area indicator of SEP.

Results During the period 2001–2005, there was a decrease in the total number of cars (−3.8%), NO₂ and PM₁₀ emissions and concentrations (from 22.9 to 17.4 μg/m³ for NO₂ and from 7.8 to 6.2 μg/m³ for PM₁₀), and in the residents' exposure. In the two low-emission zones, there was an additional decrease in air pollution concentrations (NO₂: −4.13 and −2.99 μg/m³; PM₁₀: −0.70 and −0.47 μg/m³). As a result of the policy, 264 522 residents living along busy roads gained 3.4 days per person (921 YLG per 100 000) for NO₂ reduction. The gain was larger for people in the highest SEP group (1387 YLG per 100 000) than for residents in the lowest SEP group (340 YLG per 100 000).

Conclusion The traffic policy in Rome was effective in reducing traffic-related air pollution, but most of the health gains were found in well-off residents.