Use of public health benefits to design air pollution emission abatement strategies

This study presents a framework to identify feasible urban emission control strategies, using observed changes in air pollutants and economic activities during the Mexico City COVID-19 lockdown. The novelty of our framework lies in integrating an anomaly-based observational approach with economic activity indicators and a health impact assessment (HIA) to propose potential non-lockdown emission control strategies. Unlike descriptive existing studies, our approach explicitly links short-term air quality anomalies to sectoral activity changes, allowing for the inference of likely source categories contributing to observed pollutant reductions and the translation of these findings into targeted, economically feasible policy recommendations. The framework integrates a HIA to evaluate targeted restrictions on traffic, industrial activity, and other economic sectors. NO2 and PM2.5 exhibited the largest reductions (33.6% and 20.5%, respectively) during the Full lockdown, mostly due to decreased mobility and reduced industrial operations. By contrast, O3 increased showing that solely reducing precursor emissions is insufficient for effective O3 control. Sustained reductions in NO2 (18.3%) and PM2.5 (6.5%) like those observed during the New Normal phase could prevent an estimated 1,559 premature deaths annually from PM2.5 reductions alone, with additional avoided mortality of 542 from NO2 reductions as a non-additive co-benefit, representing an optimal balance between public health gains and economic feasibility. Our results highlight that interventions targeting the transportation sector (e.g., adopting low-emission diesel and electrification) and complementary policies in construction would further enhance emission reductions both in NO2 and PM2.5 without excessive economic costs. Although reductions in PM2.5 yield the greatest estimated avoided mortality, reductions in NO2 are an important co-benefit of mitigation strategies focused on the transport sector, yet these should not be prioritised over PM2.5. This framework provides a robust basis for designing integrated emission abatement strategies by emphasising the joint consideration of NO2 and PM2.5, and is adaptable for other urban areas in economically developing countries.