Future climate change decreases multi-pathway but increases respiratory human health risks of PAHs across China

Abstract

Future climate change will affect the environmental fate of hydrophobic organic contaminants (HOCs) and associated human health risks, yet the extent of these effects remains unknown. Here, we couple a high-resolution environmental multimedia model with a bioaccumulation model to study the multimedia distribution of 16 priority polycyclic aromatic hydrocarbons (PAHs), a group of HOCs, and assess future PAH-related human health risks under varying climate change scenarios over China at a continental scale. After removing the effects of PAH emission changes, we find that the total PAH concentrations would decrease in the air, freshwater, sediment, soil, and organisms, while the high-molecular-weight PAH would increase in the air with climate warming from 1.5°C to 4°C. Consequently, the multi-pathway exposure human health risks predominately influenced by dietary ingestion are expected to decrease by 1.7%–20.5%, while the respiratory risks are projected to rise by 0.2%–5.8% in the future. However, the persistently high multi-pathway human health risks underscore the need for reducing future PAH emissions by 69% compared with 2009 levels in China. Our study demonstrates the urgency of limiting PAH emissions under future climate change for public health and highlights the importance of including the contribution of dietary ingestion in human health risk assessment.

Keywords

• polycyclic aromatic hydrocarbons
• future climate change
• human health risks
• emission reduction