Putting Low Emission Zones (LEZs) to the test: the effect of London’s LEZ on education

Low Emission Zones (LEZs) have been implemented in many cities around the world as a way of tackling the problem of air pollution by restricting road traffic for more polluting vehicles. Despite the well-documented link between air pollution and educational achievement, there has been no thorough evaluation of the effect of LEZs on standardised exam results. This paper helps to fill that gap by evaluating the impact of London’s LEZ on test scores among primary [elementary] school students.

Utilising administrative data for the years 2005–2015, the authors assess the London LEZ’s effect on standardised Key Stage 2 results, from tests sat at age 10/11. The analysis reveals a statistically and economically significant improvement in test scores for students located within the LEZ compared with those in a control group. Importantly, it also finds that the LEZ policy has larger positive effects in low-performing schools, demonstrating its potential to significantly reduce educational disparities, and growing positive impacts over time.

Key points for decision-makers

• Assessments taken at age 10/11 at the end of Key Stage 2 serve as a crucial benchmark in England and Wales for evaluating students’ academic progress at the end of their primary education.
• The Greater London LEZ was introduced in 2008, using pricing and fines to disincentivise the use of highly polluting vehicles across almost all of Greater London, which has a population of nine million people over approximately 1,600 square kilometres.
• Utilising data from the National Pupil Database, the authors show that primary schools within the LEZ experienced a meaningful improvement in Key Stage 2 test scores – an average 0.09 standard deviation improvement relative to a control group located across 20 other cities in England.
• The magnitude of this effect is similar to reducing class size by 10 students or paying teachers large financial bonuses, and almost equivalent to significantly increasing average teacher quality.
• The benefits were disproportionately greater in schools serving a larger share of economically disadvantaged populations and those with historically lower academic performance. This indicates that LEZs can play a critical role in levelling the educational playing field and supporting vulnerable communities, with knock-on impacts on labour market opportunities.
• The positive effect appears to increase over time, suggesting that prolonged reductions in pollution concentrations yield increasingly significant improvements in educational outcomes. This highlights the critical role of time in the realisation of policy benefits.