Air Pollution Effects on Urban Wildlife: A Comprehensive Review

Abstract

Air pollution has emerged as one of the most significant environmental challenges accompanying rapid urbanization since the mid-twentieth century. Between 1947 and 2017, industrial expansion, increasing vehicular emissions, fossil fuel combustion, and urban growth substantially altered atmospheric quality worldwide. While considerable research has focused on the impacts of air pollution on human health, its influence on urban wildlife has received comparatively less attention. Urban ecosystems support diverse fauna, including birds, mammals, reptiles, amphibians, insects, and pollinators, all of which are exposed to a complex mixture of airborne pollutants such as particulate matter (PM), sulfur dioxide (SO₂), nitrogen oxides (NOₓ), ozone (O₃), carbon monoxide (CO), volatile organic compounds (VOCs), and heavy metals. These pollutants affect wildlife through inhalation, ingestion, dermal exposure, and contamination of food chains. Long-term exposure has been associated with respiratory disorders, reproductive impairment, behavioral changes, immune suppression, genetic damage, reduced biodiversity, and altered species distribution. This comprehensive review synthesizes seven decades of scientific literature (1947–2017), tracing the evolution of research on air pollution and urban wildlife. It examines historical trends, major pollutants, biological responses across taxa, ecological consequences, methodological developments, and emerging conservation strategies. The review also identifies significant knowledge gaps and proposes future research priorities for sustainable urban biodiversity management. Understanding these relationships is essential for integrating wildlife conservation into urban planning and air quality management, thereby supporting healthier ecosystems and resilient cities.

Keywords- Air Pollution, Urban Wildlife, Biodiversity, Particulate Matter (PM), Heavy Metals, Birds, Urban Ecology, Environmental Monitoring