Environmental performance of Malaysia’s air pollutants based on data envelopment analysis with slack-based measure and Malmquist productivity index

Abstract

Air pollutants have a significant impact on humans and the environment, making their reduction and mitigation crucial and requiring attention from policymakers. In this study, the impact of air pollutant concentrations, namely particulate matter with an aerodynamic diameter less than 10 μm (PM10), particulate matter with an aerodynamic diameter less than 2.5 μm (PM2.5), sulphur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3) and carbon monoxide (CO) on the environmental performance of 15 states in Malaysia was examined using available data from 2018 to 2021. The analysis was performed using data envelopment analysis (DEA) with slack-based measure (SBM) and the Malmquist productivity index (MPI). The efficiency values were used for principal component analysis (PCA) to infer the influencing factors that are highly redundant or dependent on each other. Results from SBM-DEA suggested an important aspect of gross domestic product toward efficiency score, where high efficiency values were observed for Selangor, Kuala Lumpur, and a small state like Perlis (efficiency value of 1.000). The MPI score indicated that the performance of each state was relatively low for the years 2019–2020, which suggested a regression in performance productivity due to the haze episode. PCA analysis showed that there were two factors, where the highest contribution for Factor 1 was Melaka and Johor with an average contribution of 8.15% and for Factor 2 was Perlis and Perak with an average contribution of 23%. This study’s findings showed that air pollutants play significant roles in achieving good environmental performance in order to tackle global issues such as global warming and climate change.