Ozone levels in relation to its precursors: NOx , NMVOCs and CH4

The revised Directive on Ambient Air Quality (AAQD, 2024/2881) strengthens the European policy on ozone pollution control, notably by aligning health objectives with WHO recommendations, expanding monitoring requirements for precursors—including methane—and mandating the development of air quality plans when target values are exceeded. While significant progress has been made since 1990, with substantial reductions in emissions of NOx, NMVOCs (non-methane volatile organic compounds), and CH₄, challenges remain, linked to certain sources that are on the rise and to monitoring networks that are still fragmented. Coordinated strategies at the national and international levels, supported by source-attribution diagnostic tools, are essential to effectively reduce ozone levels and protect public health in Europe.