Researchers from France's Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (Inrae) have introduced a new environmental indicator called the "particulate plastic footprint" (EPP). This tool measures the spread of micro and nanoplastics — tiny plastic particles that form as plastic products break down over time — from sources like tires, polyester clothing, and plastic bottles. Unlike traditional environmental assessments that focus on carbon emissions, the EPP aims to highlight the long-term risks of microplastics, which can persist in the environment for centuries and affect living organisms. The researchers argue that carbon footprints are not sufficient to evaluate the environmental impact of plastic products. While reducing carbon emissions is important, the real danger of plastic comes from its gradual breakdown into micro and nanoplastics, which are difficult to remove from ecosystems. The EPP accounts for both immediate emissions, such as those from the production and use of plastic products, and delayed emissions, which can occur decades or even centuries later, especially in landfills or from long-lasting items. For example, a polyester t-shirt produces less carbon emissions than a cotton t-shirt — about 0.2 kg less of CO2 equivalent — but its EPP is nearly 0.2 kg, meaning it releases about 200 grams of plastic particles over its lifetime. This demonstrates that a product can appear environmentally friendly in terms of carbon emissions but still contribute significantly to microplastic pollution. Additionally, recycling plastic does not reduce its overall plastic footprint. In fact, it can increase emissions. For instance, tires release 22.6% of their mass as microplastics during use. When they are repurposed into synthetic grass for stadiums, the process accelerates their breakdown, increasing emissions by 45% compared to if they were left in landfills. The EPP is based on extensive research, including thousands of studies and data points on microplastic emissions. It differentiates between immediate and delayed emissions, with recent studies showing that landfills can begin releasing microplastics within 50 years of being filled and reach a peak after about 80 years. The researchers recommend incorporating the EPP into environmental regulations and product design to help consumers make more informed choices. They also stress that current strategies focused solely on carbon footprints or life cycle analyses of plastics are not enough, as simply transforming one degraded plastic product into another does not solve the problem. To address this, they advocate for reducing landfill use and developing plans to manage existing landfills to limit future nanoplastic emissions.