This paper aims to examine convergence of income inequality in 21 OECD countries using several empirical techniques. In particular, we have used a new panel stationarity test, which allows for structural changes and cross-sectional dependence to examine the stochastic convergence of income inequality. We also employed a time series approach, residual augmented least squares-Lagrange multiplier unit root test. The empirical results show evidence for absolute, conditional, and sigma convergence. The conditional convergence test results suggest that countries are converging, but conditional on the two structural factors-economic and population growth. The stochastic convergence test results indicate the existence of convergence at the country-specific level. The results further confirm the existence of convergent clubs among OECD countries.
Despite being directly related to anthropogenic consumption and production, researchers have paid less attention to understanding the dynamics of non-methane volatile organic compounds. The primary objective of this research is to investigate the persistence of potential shocks to non-methane volatile organic compounds in 20 developed from 1820 to 2019 performing traditional unit root approaches and a newly developed Fourier quantile unit root test. Great portion of the empirical results obtained by traditional unit root tests reveal that the sectoral non-methane volatile organic compounds follow a non-stationary process, while the Fourier quantile unit root test indicate quite different results. The Fourier quantile test shows that non-methane volatile organic compounds are stationary in the United Kingdom, Ireland, Germany, France and Austria. In the other 15 countries, government interventions to reduce non-methane volatile organic compounds can have lasting effects and success. The inferences and policy outcomes of the empirical results are discussed in the main body of the paper.
The transportation sector is the primary catalyst for environmental deterioration on a global level. Growing concerns about environmental issues caused by the overuse of fossil fuels in this industry have prompted countries to prioritize eco-friendly and energy-efficient vehicles. Electric and hybrid vehicles offer a potential solution to the global challenge of meeting carbon neutrality objectives, especially in the transportation sector. In this context, this study focuses on the comparative impact of technological development in conventional, hybrid, and electric vehicles on the load capacity factor (LCF) and carbon emissions (CO2) in the G7 countries over the period 2000-2021. For this purpose, the regularized common correlated effects (rCCE) approach is applied. The empirical outcomes indicate that (i) developments in conventional vehicles are detrimental to the environment; (ii) technological advancements in hybrid vehicles are ineffective in responding to carbon neutrality efforts; (iii) developments in electric vehicles contribute to environmental sustainability.