Which is more important, foreign direct investment inflow or outflow, on the pollution of European Union countries? Evidence from Panel Fourier symmetric and asymmetric causality.

Uncertainty remains regarding the impact of foreign direct investments on countries' environmental policies and pollution levels. Therefore, this study examines the relationship between foreign direct investment inflows, outflows, and carbon dioxide emissions for EU (European Union) member states. Accordingly, the data for the period 1993-2019 were subjected to the Panel Fourier symmetric and asymmetric causality tests for 21 EU countries.