Towards a Low Pollution Future – Lessons Learnt from Leaded Gasoline

Seminar by Prof. Dominik Weiss from Imperial College London

21 February 2023
KST 10:30 – 11:30

The Seminar is being held in Room 1010 (Jasmin) – Integrated mechanical engineering building. Click here for the campus map.

Humans have released an overwhelming amount of pollutants that fundamentally alter global biogeochemical cycles, threaten public health, and affect ecosystem functioning, which intimately links with climate change.  Managing chemical pollution is central to sustainability and is reflected in the fact that nine out of seventeen sustainable development goals set up by the United Nations involve pollution management.  Central to successful environmental policies is our ability to gauge and trace the impact of pollutants across different geographies and environments (atmospheric, terrestrial, marine), as well as its public health and economic outcomes. From its introduction into economic activities to the phasing out of leaded gasoline, lead (Pb) appears to be one of the best elements to examine how human actions impact the natural environment on global, regional, and local scales. Indeed, lead has spread globally and is traceable through its isotopes. It thus offers useful lessons for policy discussions surrounding a low pollution future.  Lead is a metal used in a wide range of products (batteries, alloys, gasoline, paints, etc.) that link to industrialization, and subsequently to societies’ prosperity. Although natural lead sources exist, anthropogenic lead emissions, especially combustion of fossil fuel (i.e. leaded gasoline, coal) has overwhelmed the global environment since pre-Roman times. At the peak of leaded gasoline usage, anthropogenic sources were responsible for more than 90% of atmospheric lead emissions, contributed more than 95% of lead in marine environments, and poisoned more than 10% of the world’s population. With all environments impacted by anthropogenic Pb, Pb has indeed been proposed as a marker for the starting of the Anthropocene.

In 2021, Algeria became the last country to outlaw lead from gasoline, half a century after the world started moving towards unleaded gasoline. Following the ban, we now witness some environments returning to pre-pollution lead concentration levels, providing an encouraging example of what multi-national collaboration and agreements can achieve. Another example of successful restoration policy is ozone.  Lead is indeed a suitable ‘thermometer’ to gauge planetary health as studying lead in the environment gives unique insights into the effects of environmental policies and into the fate of persistent inorganic pollutants in the environment. Since the banning of leaded gasoline, blood Pb levels have declined dramatically in high-income countries, resulting in a feeling that the ‘lead problem’ has been solved. However, about 1 in every 3 children today still have unsafe blood Pb levels, and it is worth noting that no safe level of lead exposure exists. Thus, understanding the changing and/or emerging source(s) of Pb pollution and the persistence of historically emitted Pb in the unleaded gasoline era remains critical to a low-pollution future.

This presentation aims to demonstrate that lead is maybe the best tracer to study human induced metal movements in the various environments, transferring from environment to humans and the residence of metal pollutants and its effect on long-term exposure. As such, the lead case study provides important lessons for the net-zero transition.