Chapter 10 Risk Factors

Environmental Pollutants and Occupational Exposures

Outdoor air pollution kills about 300,000 people every year from lung cancer alone.

Cancer-causing environmental pollutants can occur naturally (e.g., radon or arsenic) or are man-made (e.g., air pollution from burning fuels), and they can be found in the air, soil, or water. Radon, a radioactive gas that can accumulate in buildings, is the second leading cause of lung cancer in many countries, after tobacco use. Elevated levels of arsenic in drinking water or soil have been found in parts of Asia and throughout the Americas and are linked to an increased risk of skin, lung, and bladder cancer.

“The places where we live, work, and play should nurture us, not harm us.”

—Dr. Tedros Adhanom Ghebreyesus WHO Director-General

Outdoor air pollution level is particularly high in rapidly growing cities in low- and middle-income countries (LMICs) (Map 10.1).

Also, the use of cooking fuel (e.g., wood, other biomass, and coal) remains a major source of indoor air pollution in some of these countries, although it is declining. Overall, outdoor air pollution alone accounts for about 15% (300,000) of lung cancer deaths worldwide, with the proportion varying from 34% in Qatar and Egypt to 2% in Tuvalu and Finland (Map 10.2).

Emerging man-made environmental pollutants, such as per- and poly-fluoroalkyl substances (PFAS), are another growing concern due to their persistence in the environment and ubiquity across settings.

Numerous chemical substances and physical agents are known to cause cancer in occupational settings (Figure 10.1). Occupational exposure to carcinogens is particularly concerning in LMICs, where exposure levels may be higher and regulations and enforcement less strict.

Figure 10.1

Examples of occupational carcinogens and associated cancer types

Radiation Exposures Airborne Particles Metals and Metalloids Chemicals and Chemical Mixtures Pesticides
X and Gamma
Nuclear industry,
Medical Imaging
Ultraviolet
Outdoor work,
Welding
Plutonium
Nuclear industry
Asbestos
Mining, Shipyards,
Manufacturing
Wood Dust
Forestry, Carpentry,
Construction
Acid mists
Soap manufacturing,
Phosphate fertilizers,
Electroplating, Pickling
Soot
Industries and tasks with
combustion products
Arsenic
Manufacturing, Metal
Refining, Agriculture
Chromium/Nickel
Mining, Smelting and
Refining of Metal, Paints
Coal Tar/Pitch
Roofing, Asphalt Laying
Formaldehyde
Manufacturing,
Hospital Disinfection
Benzene
Manufacture and use of
Paints/Glues/Chemicals,
Petrol distribution
Lindane
Wood treatment,
Agriculture
Pentachlorophenol
Wood treatment,
Agriculture,
Waste Incineration
Bladder
Bone
Brain
Breast
Colon
Esophagus
Eye
Hematolymphatic
Kidney
Larynx
Leukemia
Liver
Lung
Mesothelioma
Nasal
Nasopharynx
Non-Hodgkin lymphoma
Ovary
Salivary Gland
Skin
Stomach
Thyroid

Certain occupations, such as rubber manufacturing, are associated with prolonged exposure to these agents, increasing the risk of stomach, lung, and bladder cancer among workers (Figure 10.2). Enforcing laws and regulations is critical to ensure removal or substitution of carcinogenic materials, implementation of engineering solutions, and adequate provision of personal protective equipment to minimize, reduce, or eliminate exposures.

Figure 10.2

Examples of occupations and associated cancer types

Rubber manufacturing Isopropyl alcohol manufacturing Acheson process Aluminum production Coal gasification Coke production Haematite mining Iron and steel founding Painter Welding fumes Coal-tar distillation Firefighter
Bladder
Hematopoietic and lymphatic systems
Lung
Mesothelioma
Nasal
Skin
Stomach

Sources

Text

  • World Health Organization. WHO Handbook on Indoor Radon: A Public Health Perspective. Geneva: World Health Organization; 2009.
  • Podgorski J, Berg M. Global threat of arsenic in groundwater. Science. 2020/05/22 2020;368(6493):845-850. doi:10.1126/science.aba1510
  • World Health Organization. Global Heath Observatory: Air pollution data portal. https://www.who.int/data/gho/data/themes/air-pollution. Accessed July 12, 2024.
  • IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, International Agency for Research on Cancer. Outdoor Air Pollution: IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Vol. 109, IARC monographs. Lyon, France: International Agency for Research on Cancer; 2016.
  • Gordon SB, Bruce NG, Grigg J, et al. Respiratory risks from household air pollution in low and middle income countries. Lancet Respir Med. Oct 2014;2(10):823-60. doi:10.1016/s2213-2600(14)70168-7
  • Zahm S, Bonde JP, Chiu WA, et al. Carcinogenicity of perfluorooctanoic acid and perfluorooctanesulfonic acid. Lancet Oncol. Jan 2024;25(1):16-17. doi:10.1016/s1470-2045(23)00622-8
  • Pruss-Ustun A, Wolf J, Corvalan C, Bos R, Neira M. Preventing Disease Through Healthy Environments: A global assessment of the burden of disease from environmental risks. World Health Organization. Geneva; 2016.
  • Espina C, Porta M, Schüz J, et al. Environmental and Occupational Interventions for Primary Prevention of Cancer: A Cross-Sectorial Policy Framework. Environmental Health Perspectives. 2013/04/01 2013;121(4):420-426. doi:10.1289/ehp.1205897

Maps

  • Map 10.1 and 10.2: Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990-2021: a systematic analysis for the Global Burden of Disease Study 2021. Lancet. May 18 2024;403(10440):2162-2203. doi:10.1016/s0140-6736(24)00933-4

Figures

  • Figure 10.1: International Agency for Research on Cancer. List of Classifications - IARC Monographs on the Identification of Carcinogenic Hazards to Humans. https://monographs.iarc.who.int/list-of-classifications. Accessed July 12, 2024.
  • Figure 10.1: Loomis D, Guha N, Hall AL, Straif K. Identifying occupational carcinogens: an update from the IARC Monographs. Occup Environ Med. Aug 2018;75(8):593-603. doi:10.1136/oemed-2017-104944
  • Figure 10.2: International Agency for Research on Cancer. List of Classifications - IARC Monographs on the Identification of Carcinogenic Hazards to Humans. https://monographs.iarc.who.int/list-of-classifications. Accessed July 12, 2024.