REVIEW ARTICLE The association between air pollution and cancers: controversial evidence of a systematic review Negar Pourvakhshoori 1,2 & Hamid Reza Khankeh 3 & Marcus Stueck 4 & Mehrdad Farrokhi 2 Received: 13 May 2020 /Accepted: 3 August 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract There are inconsistent reports on the association between air pollution and cancers. This systematic review was, there- fore, conducted to ascertain the relationship between air pollution and some cancers. This is a systematic review study, which all articles published in this area were extracted from January 1, 1950 to December 31, 2018 from Web of Science, PubMed, Scopus, Cochrane Library, MEDLINE, EMBASE, Science Direct, Google scholar. Searching was performed independently by two search-method experts. The required data were extracted from the articles by an author- made questionnaire. Forty-eight articles were investigated. Evidence linking air pollution to some cancers is limited. Leukemia had the highest association with exposure to various air pollutants and bladder cancer had the lowest asso- ciation. It is noteworthy that the specific type of pollutants in all studies was not specified. Based on the findings, the results are contradictory, and the role of air pollution in some cancers cannot be supported. Accordingly, studies are recommended to be performed at the individual level or multifactorial studies to specifically investigate the relationship between air pollution and these types of cancers. In this way, the role of air pollution in the incidence of these cancers can be determined more accurately. Keywords Air pollution . Cancer . Systematic review Introduction With the industrialization of the countries around the world, air pollution has increased over the recent decades, to such an extent that in some cases, it has threatened the life of human beings (Newby et al. 2015; Pourvakhshoori et al. 2020; Straif et al. 2013). The main factors influencing air pollution include the use of motor vehicles, industrial activities, mining activi- ties, power plants, and the use of fossil fuels. Human beings are exposed to air pollutants at all kinds of places, including home, work, public areas, public transport vehicles, and open air. They can be introduced through breathing, foods, and skin contact, which may ultimately lead to various types of respi- ratory and cardiac morbidities and cancers (Bazyar et al. 2019; Bräuner et al. 2010; Weng et al. 2008). Investigation of the disease burden resulting from the air pollution in 2016 by the World Health Organization (WHO) showed that 4.2 million fatalities have been recorded due to global air pollution, 262,000 of which have been due to lung cancer (Ha et al. 2017). Cancer is the second cause of increased disease burden and fatality in the world. Every year, there are many fatalities from cancer worldwide, such that, according to the WHO report from 185 countries, in 2018, 18.1 million new cases of cancer and 9.6 fatalities due to the disease occurred. Most of the cases were related to lung, breast, colorectal, prostate, and gastric cancers. Also, lung and breast cancers were the leading cause of mortality in men and women, respectively (Janitz et al. 2016). According to the World Health Organization (WHO), various factors have contributed to the increase in cancer in- cidence and its resulting mortality including population Responsible editor: Lotfi Aleya * Mehrdad Farrokhi mfarokhikhb@yahoo.com 1 Department of Nursing, School of Nursing and Midwifery, Guilan University of Medical Sciences, Rasht, Iran 2 Health in Emergency and Disaster Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran 3 Department of Clinical Science and Education, Karolinska Institute, Stockholm, Sweden 4 DFPA University of Applied Sciences Saxony, Germany; International Research Academy BIODENT, Leipzig, Germany Environmental Science and Pollution Research https://doi.org/10.1007/s11356-020-10377-z