Global impact of plastics on healthy living

The life cycle of plastics emits a whole range of gases and pollutants that have harmful effects on the environment and human health. These emissions occur at every stage of the plastics value chain, from oil extraction to plastic production, use, and degradation in the environment, making the system all the more complex to study. Although some impacts have been estimated, such as contributions to climate change due to greenhouse gas emissions, no one had yet assessed the overall impact of plastics on human health.

Reducing plastic production

Using an original hybrid approach combining material flow analysis and life cycle assessment (LCA) of plastics, this study quantitatively compares the effects on human health in terms of years of "healthy life" in different global consumption scenarios between 2016 and 2040. Material flow analysis quantifies plastic flows within a given geographical and temporal scope, while life cycle analysis measures the effects of plastic on the environment and health, from production to degradation. 

This model has thus made it possible to estimate the global health impacts of greenhouse gases, particulate matter, and certain chemical emissions associated with plastics commonly found in municipal solid waste (64% of global plastic production), from their production, transport, recycling, and end of life, as well as those associated with alternative single-use materials and glass reuse systems. The scope does not include the effects of exposure to micro- and nanoplastics or substances emitted during use, due to a lack of available inventory data.

If plastic use continues to increase in line with the current trajectory, scientists estimate that 83 million years of "healthy" life will be lost (expressed as disability-adjusted life years (DALYs**) worldwide by 2040. This figure corresponds to the cumulative DALYs associated with the status quo scenario between 2016 and 2040. It is obtained by combining the annual plastic flows from the Plastics-to-Ocean model with LCA impact factors (expressed in DALYs per ton), calculated from life cycle inventories, and then summing the contributions from all stages and all years. 

The most ambitious scenarios showed that, in 2040, up to 43% of annual impacts (in terms of DALYs) could be mitigated relative to a business-as-usual scenario by combining several actions: reducing total global production of virgin plastics, improving waste collection and disposal, increasing recycling, and replacing certain plastics with alternative materials and reuse systems. Furthermore, reducing virgin plastic production without substituting materials is the single most effective lever for reducing emissions and alleviating the associated health burdens. Emissions from primary plastic production were the main cause of health effects in all scenarios.

A tool to support public policy

Using this assessment model, which quantifies the harmful impacts of plastics on human health throughout their life cycle, scientists hope to contribute to the development of effective policies to combat plastic pollution. In order to make the transition, this study shows that it is necessary to plan for significant reductions in primary production today, with assessments that take into account the impact of plastics in all sectors, including during their use. This implies, in particular, making the composition of plastics available, which is not currently the case. 

*London School of Hygiene and Tropical Medicine and University of Exeter

** DALYs is an indicator used particularly in the Global Burden of Disease estimates, which corresponds to the number of years of "healthy" life lost for each health problem.