Background

Project Purpose

This project aspires to analyze the relationship between air pollution and lung cancer, in order to address a topic within the framework of the United Nation's Sustainable Development Goals, namely Goal 3 - Good Health and Well-being. More precisely, an analysis is made of lung cancer mortality rates and air pollutant emissions in 32 European countries from the 1990 until 2020. For this purpose, data from the World Health Organization (WHO) was taken regarding the death burden due to lung cancer. With regard to air pollution, the source of the data is the European Environmental Agency (EEA) in which values are given for the following pollutants expressed in Gg (1 Gg = 1000 tonnes) for each year: Carbon Monoxide (CO), Sulphur Oxide (SO_x), Nitrogen Oxide (NO_x), Particulate Matter (PM2.5 and PM10), Non-methane volatile organic compounds (NMVOC), Ammonia (NH₃) and finally the Total Suspended Particulate matter (TSP). The project consists of an interactive map with the individual data for each year and graphs of additional information attached.

Research Question: Is there a correlation between lung cancer and air pollution?

Sub-Questions:

Which pollutant is most prevalent in countries with a high death rate?
Has the mortality rate reduced due to the decreasing amount of pollutants in the air?
Does a high death rate imply high pollutant values? Or respectively a minimal rate for low values?

What are the Sustainable Development Goals?

The Sustainable Development Goals (SDGs) are a collection of 17 goals and 169 targets set by the United Nations, adopted by all member states in 2015 as part of the 2030 Agenda (UNO, 2015). The latter provides a shared agenda for peace and prosperity for people and the planet, now and in the future. These goals recognize that ending poverty and other deprivations must go hand in hand with strategies that improve health and education, reduce inequalities and stimulate economic growth, all while tackling climate change and working to preserve our oceans and forests (UNO, 2015).

SDGs related to Air Pollution and Lung Cancer

Concerning the topic of health and the related challenges due to pollution, WHO has worked to ensure that health-relevant indicators of household and ambient pollution exposure and disease burden are included in the formal system of SDG indicators (WHO, 2023a). In detail, the WHO identified a group of three specific targets related to air pollution:

SDG target 3.9.1, which calls for a substantial reduction in deaths and diseases caused by air pollution.
SDG target 7.1.2, which aims to ensure access to clean energy in homes.
SDG target 11.6.2, which aims to reduce the environmental impact of cities by improving air quality.

Central to this project is the target 3.9.1, which belongs to the main Goal 3 (hover on the image below to discover more). The SDG 3 aims to ensure healthy living and promote well-being for all at all ages.

Sustainable Development Goal 3

Ensure healthy lives and promoting well-being for all at all ages.

Discover more on SDG 3 and its targets

The relation between Air Pollution and Lung Cancer

As indicated by Gawelko et al. (2022) lung cancer is the second most common cancer and the most prevalent among men worldwide. According to Cohen (2003), lung cancer alone is responsible for 1.2 million deaths per year worldwide, exceeding mortality from any other cancer in developed countries. After cigarette smoking, studies point to occupational exposure, radon and air pollution as major causes (Gawelko et al., 2022; Yurifuji & Kashima, 2013). As stated by the EEA (2022) air pollution is a major environmental risk for health in Europe, where despite progress made in the past decades, the pollution levels are still far from safety levels. Furthermore, the EEA (2022) noted that 91% of the urban population in Europe is exposed to concentrations of air pollutants that exceed World Health Organization (WHO) air quality guidelines. Air pollution is a major cause of morbidity and mortality worldwide; studies conducted over the past four decades show that exposure to outdoor air pollution has been associated with small relative increases in lung cancer (Gawelko et al., 2022; Turner et al., 2020; Raaschou-Nielsen et al., 2016; Yorifuji & Kashima, 2013). Air pollution may be linked to 0.5-1% of all cancer cases in Europe and to more than 7% of lung cancers (EEA, 2022).

Koolen & Rothenberg (2019) stated that quantifying the effects of specific pollutants is difficult due to periodic variations in pollution levels and correlation effects between pollutants. Nonetheless, extensive studies conducted in Europe and North America have highlighted and confirmed the association between the PM, particularly the smallest particles (PM2.5), and lung cancer (Raaschou-Nielsen et al., 2016; Yorifuji & Kashima, 2013). On that regard, more than 300,000 premature deaths each year are attributed to chronic exposure to fine particulate matter (PM2.5) alone (EEA, 2022). Particularly for PM2.5, no safe threshold exists, and thus any reduction of this pollutant may have benefits for the public health (Yorifuji & Kashima, 2013). Gawelko et al. (2022) noted that the concentrations of SO₂ and NO₂ have a synergetic effect with PM, being potentially the main cause of appearance of squamous lung cancer. Xue et al. (2022) review highlighted how many chemical pollutants commonly found in air pollution such as NO_x and SO₂ are associated with increased lung cancer risk and lung cancer mortality. Finally, it is important to notice that, as remarked by the EEA (2022), while pollution has decreased in the past decades in many European countries, cancer has a long latency period, so current cases mostly reflect past exposures.

About the Different Pollutants

The pollutants considered for this project are displayed and described in Table 1 below, where are given further details on their effect on human health.

*Table 1: Description of the pollutants investigated in this project and their health consequences.*
Pollutant	General Information	Effects on Human Health
Particulate Matter (PM)	As defined by the WHO (2023b) particulate matter (PM) refers to inhalable particles, composed of sulphate, nitrates, ammonia, sodium chloride, black carbon, mineral dust or water. PM can be of different size and is generally defined by their aerodynamic diameter, with PM2.5 and PM10 the most common in the regulatory framework and relevant for health. PM10: diameters of 10 µm or less. PM2.5: diameters of 2.5 µm or less. PM can be emitted directly from construction sites, unpaved roads, fields, chimneys or fires. Most PM is formed in the atmosphere as a result of chemical reactions of various compounds, such as SO₂ and NO_x (Gawelko et al., 2022; Turner et al., 2020).	Exposure to PM10 and PM2.5 can affect the lungs and heart, causing various diseases and even fatal cases (WHO, 2023b). Numerous studies indicate a causal link between PM and lung cancer (Turner et al., 2020; Raaschou-Nielsen et al., 2016; Yurifuji & Kashima, 2013).
Carbon Monoxide (CO)	Carbon monoxide (CO) is a colourless, odourless gas produced by the incomplete combustion of fuels such as wood, oil, coal or natural gas in simple stoves, open fires, wick lamps, furnaces, fireplaces. Main source in ambient air is from motor vehicles. (WHO, 2023b).	High CO concentrations reduce the amount of oxygen that can be transported to the heart and brain and can cause dizziness, confusion, loss of consciousness and death (WHO, 2023b).
Sulphur Oxide (SO_x)	SO₂ is largely derived from the combustion of fossil fuels for domestic heating, industries and power generation (WHO, 2023b).	Short-term exposure to SO₂ can damage the human respiratory system both directly and through the formation of small particles known as PM2.5; SO_x has been associated by various studies to lung cancer (Xue et al, 2022; Gawelko et al., 2022; Turner et al., 2020)
Nitrogen Oxide (NO_x)	Nitrogen oxides (NO_x) are highly reactive gases. Ambient sources of NO₂ are high temperature combustion of fuels, for instance for heating, transportation, industry and power generation. Household sources of nitrogen oxides (NO_x) are furnaces, fireplaces and gas stoves and ovens. (WHO, 2023b)	NO₂ can irritate the respiratory tract, aggravate asthma and increase susceptibility to respiratory infections (WHO, 2023b). NO_x has been associated by various studies to lung cancer, either directly or indirectly, due to reaction with other compounds in the atmosphere and consequent formation of PM (Xue et al, 2022; Gawelko et al., 2022; Turner et al., 2020).
Non-methane volatile organic compounds (NMVOC)	Non-methane volatile organic compounds, or NMVOCs, is the collective name for many gaseous organic compounds, excluding methane, which at a temperature of 293.15° K have a vapor pressure of 0.01 kPa or more. NMVOCs are emitted into the air during incomplete combustion and by vaporization. Today, the most important source is the evaporation of solvents as part of the sector's product use. (Natur Vards Verket, n.d.)	Volatile organic compounds contribute, together with nitrogen oxide and sunlight, to the formation of tropospheric ozone. Which can irritate the respiratory tract (Natur Vards Verket, n.d.). Also, some components of NMVOC are associated with increased risk for lung cancer, already at low concentrations. (Xue at al., 2022)
Ammonia (NH₃)	Ammonia (NH₃) is a corrosive, colorless gas with a characteristic, pungent odor. Commonly found in nature, ammonia can be stored as a liquid under high pressure and is easily soluble in water. Ammonia is deposited in wet and dry form on soil, plants, soils and water. Ammonia is an air pollutant and a precursor of secondary particulate matter. It combines with other compounds in the atmosphere, such as nitric and sulphate acids, to form ammonium salts, a harmful form of fine particulate matter. (IQAir, 2016)	Exposure to high concentrations of ammonia in the environment can cause irritation to the eyes, nose, throat and skin. Long-term health problems associated with ammonia exposure include: serious cardiovascular and respiratory effects reduced lung function aggravation of asthma premature death (IQAir, 2016) Indirectly linked to lung cancer since through reaction with other particles in the atmosphere can form PM (Turner et al., 2020).
Total Suspended Particulate (TSP)	Refers to the totality of small solid matter released, documented and/or otherwise observed in the atmosphere. Total suspended particulates are considered to be a primary contributor to air pollution, smog formation and environmental contamination. (Corrosionpedia, 2018)	Short-term health effects include increased mortality, morbidity and deficits in pulmonary function (EEA, 2020).