THE IMPACT OF CLEAN ENERGY RESEARCH AND DEVELOPMENT, HEALTH EXPENDITURE, AND ECONOMIC GROWTH ON ENVIRONMENTAL QUALITY

This study investigates the impact of clean energy technologies, health expenditure, and economic growth on environmental quality using the Fourier Engle-Granger cointegration method for the United States in the 1974–2022 period. The Fourier approach successfully identifies gradual structural shifts and nonlinear dynamics in long-run relations, which are frequent in macroeconomic and environmental time series but are typically overlooked by standard approaches. The findings show that clean energy research and development investment—specifically in energy efficiency, renewable resources, and nuclear technologies—and health expenditures significantly positively impact environmental quality. However, economic growth has a negative impact environmental quality in the United States. These results highlight the necessity of integrating environmental objectives into energy and health policy and prioritizing investment in sustainable technologies to achieve ecological sustainability in the long term.