[RETRACTED] UNRAVELING THE ORIGIN OF COVID-19 PANDEMIC: A CRITICAL REVIEW ON THE ROLE OF NITROGEN DIOXIDE EXPOSURE

Six years after the onset of the COVID-19 pandemic, the world remains without conclusive evidence of how this unprecedented global health crisis originated. Despite extensive international research efforts, and two major investigative studies coordinated by World Health Organization in 2021, and 2025, important aspects of the pandemic’s origin remain unknown. The continued absence of conclusive evidence suggests that the prevailing explanatory framework may be incomplete. Over time, a growing number of studies has uncovered inconsistencies that raises fundamental questions about the validity of the initial causal attribution to SARS-CoV-2. Therefore, further studies are necessary to confirm or refute this assumption. This study challenges, and critically re-examines the assumption that SARS-CoV-2 was the causal agent of the COVID-19 pandemic. A comprehensive narrative review was conducted following a pilot search, with systematic searches of five electronic databases (Web of Science Core Collection, Scopus, CAB Abstracts, PubMed, and EMBASE). Given the global and prolonged nature of the pandemic, publications spanning multiple years were included. Eligible studies were peer-reviewed articles reporting clinical, molecular, epidemiological and environmental data relevant to COVID-19 or nitrogen dioxide (NO₂) exposure, with peer-reviewed literature prioritized over preprints. Satellite-based Sentinel-5P data were used to map tropospheric NO₂ concentrations over Wuhan, China, and other early epicenters of the COVID-19 pandemic during December 2019 and January 2020. Through integrated review and analysis of clinical, epidemiological, toxicological, and environmental data, this study shows that the clinical and pathological features attributed to COVID-19 were consistent with documented effects of nitrogen dioxide inhalation, and provides a compelling evidence that the respiratory illness attributed to SARS-CoV-2 infection was the result of exposure to high levels of atmospheric nitrogen dioxide (NO₂) pollution levels in Wuhan, China, and all around the world. This study redefines the COVID-19 pandemic as a large-scale manifestation of nitrogen dioxide pollution-induced respiratory disease, and underscores the importance of transparent, scientifically rigorous, and multidisciplinary approaches in identifying the causes of global public health emergencies and highlights the need to broaden investigative frameworks beyond conventional pathogen-centered models.