Consumption-based human health impacts of primary PM_2.5: The hidden burden of international trade

International trade separates the consumption of goods and services from their production as well as human health impacts associated with production-based environmental emissions. It is one of the drivers of fine particulate matter (PM_2.5), particles <2.5 μm diameter, which is a leading environmental health risk factor associated with several adverse effects on human health, but its importance is not fully characterized. This study quantifies global economic output and PM_2.5-related human health impacts caused by the consumption of 189 nations. The results show that in 2010, 23% of global economic output and 26% of global PM_2.5-related human health impacts (4.1 million DALY, disability-adjusted life year losses) were caused by the production induced by other nations. Developed nations (e.g., the U.S., Japan, and Germany) outsource not only economic production but also PM_2.5-related human health impacts (14%) to Asia (e.g., China and India). An average North American consumer induced nearly as much economic output in Asia as an average Asian consumer. North American consumers induced 596 thousand DALY in Asia in 2010, while Asian consumers induced only 19 thousand DALY in North America. International joint efforts between developed nations and Asia are important to effectively reduce global PM_2.5-related human health impacts.