Abstract

Developing countries have seen rapid economic growth, but they have also faced unprecedented environmental challenges, including air pollution, water pollution, land pollution, waste pollution, etc. Take air pollution as an example. It is alarming that 99 percent of the world’s population breathes polluted air. Air pollution is deemed a “quiet killer”, giving rise to numerous consequences ranging from health and psychological impacts to economic and social costs. For example, air pollution annually causes roughly 7 million premature deaths and an economic loss of USD 8.1 trillion, accounting for 6.1% of the global GDP. Furthermore, it is worth noting that the urban population is projected to exceed two-thirds of the total global population by 2050, as urbanization exacerbates the air pollution problem, creating even more air pollution challenges for humankind in the long run. Every new piece of information matters for scientific progress in air pollution assessment, policymaking, and public health protection. From this viewpoint, the goal/objective of this Special Issue (SI) of Urban Science is to keep communities, scholars, and policymakers informed on the research progress on air quality and human health. Specifically, this SI serves as a forum for advancing scientific understanding of environmental changes associated with air pollution and air quality, strategies and/or different measures that the public, particularly urban residents, can employ to lessen and/or mitigate unexpected impacts. I hope that the useful information and insightful findings presented by scholars in this SI can support or facilitate desirable urban environment policies that help, ultimately, increase human and societal wellbeing.