Global emissions of polychlorinated naphthalenes from 1912 to 2050.

Polychlorinated naphthalenes (PCNs) are persistent organic compounds that are regulated by the Stockholm Convention. Here, we estimate historical emissions from PCN production and use (1912-1987) and unintentional emissions from 20 categories (2000-2020). A random forest regression model projects emissions for 2020-2050. A global high-resolution 1 km × 1 km PCN emissions inventory is developed for 2020. The results show that 468,014 t of PCNs were emitted from historical production, with 96.6% of emissions occurring during product use, the majority of cumulative PCN emissions (99.4%) entering the atmosphere. Total unintentional emissions from 2000-2020 are 11,534 t. Global emissions of PCNs are 293.5 t (15.8 kg TEQ) in 2020, with municipal waste incineration as the major source (98.0%) and West Central Asia being the major emission region. Future PCN emissions may experience fluctuations, with projected changes ranging from a decrease of 29% to an increase of 347%.