The health effects of air pollution and its sources

Ahmed Khabbush
Dec 3, 2019 · 7 min read

Air pollution has been a growing concern in recent decades. Poor air quality is a component of the rise in global warming; as more greenhouse gases are released into the atmosphere the worse the quality of the air becomes. Climate change is not the only negative consequence of poor air quality. There are many health risks that are linked to pollution, especially in dense cities.

Guo et al. (2003) conducted a study on the air quality of different indoor environments which included offices, homes, air-conditioned classrooms, shopping malls, and restaurants in Hong Kong.[1] The research focused on “BTEX chemicals”: benzene, toluene, ethylbenzene, and xylene. The BTEX chemicals were predominantly found to originate from indoor sources, except for in schools where they mostly came from outdoors. The concentrations of BTEX pollutants were found to be different in varying indoor environments. The highest concentration of BTEX was found to be in shopping malls. And in restaurants, the concentrations of benzene, toluene, and ethylbenzene were second-highest, although the xylene concentrations were higher in offices than in restaurants.

In 2017 the Chinese Hotel, Restaurant & Institutional (HRI) food sales reached $583 billion (Goh et al., 2013).[2] This is a part of the economic success that China has enjoyed over the last few decades, and thus the rising income levels allowing consumption to reach an all-time high. Unfortunately, research has shown that restaurants are culpable of releasing high concentrations of “organic aerosols” into the air in the immediate surroundings. The Guardian (2019) highlights a study done in Pennsylvania and Pittsburgh using a van with air quality instruments was recording the particle pollution around the cities.[3] It was found that the pollution was greater in areas that are downwind from restaurants than compared to major roads. The restaurant pollution is able to spread hundreds of metres into residential areas.

BTEX pollutants are widely recognised for their greenhouse gas contributions but also have potentially detrimental effects on the human health. Exposure to BTEX pollutants for long periods of time and at higher concentrations, in places such as the office space, can be toxic. Damage can be caused to the liver, kidneys, nervous system and eyes. Inhalation of ground-level ozone, in which BTEX can be a precursor for the formation of ozone, is linked to causing or exaggerating respiratory conditions such as asthma (SEPA, 2019).[4]

Indoor sources can depend on the source characteristics such as land type, traffic conditions, cooking style/stoves, and smoking. BTEX levels in the air can vary depending on the time of year, as consumption changes due to seasonal factors. According to the EPA, levels of volatile organic compounds have been found to be 2 to 5 times higher indoor in homes than the outdoors, and this can rise to over 1000 times more depending on activities such as painting in the home. Another example, in an office, the windows may be opened during the summer, but this allows in emissions from possible traffic. Conversely, in the winter the windows are likely to be closed which, instead, builds up CO2 levels due to the lack of ventilation and the respiration from employees (BBC, 2018).[5] Some symptoms of poor indoor air quality can be identified such as drowsiness, headaches, nausea, allergic reactions, conjunctival irritation and many more.

A variation of cardiovascular diseases is the number one cause of deaths around the world annually (WHO, 2019).[6] In a study by Polichetti et al. (2009), the effects of different particulate matter (PM1, PM2.5 and PM10) on the cardiovascular system were investigated. The research looked at “short term” and “long term” consequences of exposure to the named particulates and the development of cardiovascular diseases. Polichetti et al. reviewed a plethora of studies and found that air pollution in the environment has contributed significantly to the rise in admissions for cardiovascular diseases.[7] Additionally, Peters et al. (2004) had indicated that exposure to concentrated PM2.5 for short amounts of time increases the risk of developing myocardial infarction in a high-risk population.[8]

A statistical study conducted by Bretón et al. (2017) concluded that it could be concluded that the population of the target region, Metropolitan Area of Merida in Mexico, were exposed to a “definitive” risk of suffering from cancer at some point in their lifetime due to the inhalation of benzene.[9] By using the conclusions reached by Guo et al. (2003) we can suggest that people in shopping malls are at most risk from carcinogenic particulates, followed by those in restaurants. Those in office spaces are exposed more to xylenes which can trigger acute and chronic symptoms in a person. Xylene vapour can cause symptoms such as dizziness, headaches, vomiting and nausea, however, there is insufficient evidence to suggest that it has any carcinogenic effects (Kandyala et al., 2010).[10]

India is also a country that is suffering greatly from air pollution and thus has been burdened with disproportionately high mortality and disease rates. And as a result, 1.24 million deaths in 2017 were linked to air pollution and 480,000 of these deaths were due to indoor pollution. Furthermore, over half of the deaths that were attributable to bad air quality were people under the age of 70. The recommended limit of PM2.5 set by the National Ambient Air Quality Standards in India is 40 μg/m3. At least 76.8% of the population of India was exposed to a mean PM2.5 of greater than 40 μg/m3 and in cities such as Delhi, values exceeded 125 μg/m3 (The Lancet Planetary Health, 2018).[11]

It is important to identify the sources of air pollution in order to take the necessary actions to reduce emissions and improve air quality. The region-specific emissions identified to be the most common in India are: motor vehicles, manufacturing, electricity, construction, road dust, waste burning, coal, combustion of oil and biomass in households (Gordon et al., 2018). And of these emissions, vehicle emissions are growing the fastest as incomes increase, more households can afford more vehicles. Gordon et al. (2018) also highlight the fact that biomass which is used mainly for heating is responsible for up to 30% of PM pollution in winter and in addition to this agricultural waste burning both add up to create elevated levels of pollution, especially in large cities like Delhi. [12] According to the World Health Organisation, nearly half of the world’s population utilises solid fuels for cooking and heating which creates smoke and poor indoor air quality conditions. In India, this is especially an issue where young children usually stay alongside their mothers while cooking indoors.[13]

State governments should consider this evidence and take action by educating the population on the harmful effects of air pollution implementing policies to limit the damage done to the environment and to the people. Reducing the amount of solid fuels for cooking would see a decline in polluted air related conditions caused by thick smoke. Encouraging or even subsiding cleaner methods of transport such as trains and electric vehicles would also help to curb a major source of outdoor pollution, especially in developing countries where diesel cars are still widely used. Premature deaths and illnesses can be prevented with the right measures and climate change can be tackled simultaneously. We have to act swiftly and make amends to our way of living on a personal level in our homes, and at a larger scale, our businesses and governments need to take responsibility so as a collective community we can create a change.


  • [4] (2019). Pollutant Fact Sheet. [online] Available at:
  • [9] Bretón, J., Bretón, R., Ucan, F., Baeza, C., Fuentes, M., Lara, E., Marrón, M., Pacheco, J., Guzmán, A. and Chi, M. (2017). Characterization and Sources of Aromatic Hydrocarbons (BTEX) in the Atmosphere of Two Urban Sites Located in Yucatan Peninsula in Mexico. Atmosphere, 8(12), p.107.
  • EPA (2019). Volatile Organic Compounds’ Impact on Indoor Air Quality | US EPA. [online] US EPA. Available at:
  • [3] Fuller, G. (2019). Restaurants’ contribution to air pollution revealed. [online] the Guardian. Available at:
  • [2] Goh, M., Kim, D. and Gan, C. (2013). China’s Hospitality Industry — Rooms for Growth. ATKearney.
  • [12] Gordon, T., Balakrishnan, K., Dey, S., Rajagopalan, S., Thornburg, J., Thurston, G., Agrawal, A., Collman, G., Guleria, R., Limaye, S., Salvi, S., Kilaru, V. and Nadadur, S. (2018). Air pollution health research priorities for India: Perspectives of the Indo-U.S. Communities of Researchers. Environment International, 119, pp.100–108.
  • [1] Guo, H., Lee, S., Li, W. and Cao, J. (2003). Source characterization of BTEX in indoor microenvironments in Hong Kong. Atmospheric Environment, 37(1), pp.73–82
  • [10] Kandyala, R., Raghavendra, S. and Rajasekharan, S. (2010). Xylene: An overview of its health hazards and preventive measures. Journal of Oral and Maxillofacial Pathology, 14(1), p.1.
  • [8] Peters, A., von Klot, S., Heier,M., Trentinaglia, I., Hörmann, A.,Wichmann, H.E., Löwel, H., 2004. Exposure to traffic and the onset of myocardial infarction. N. Engl. J. Med. 351, 1721–1730.
  • [7] Polichetti, G., Cocco, S., Spinali, A., Trimarco, V. and Nunziata, A. (2009). Effects of particulate matter (PM10, PM2.5 and PM1) on the cardiovascular system. Toxicology, 261(1–2), pp.1–8.
  • [5] Stokel-Walker, C. (2019). The hidden air pollution inside your workplace. [online] Available at:
  • [11] The impact of air pollution on deaths, disease burden, and life expectancy across the states of India: the Global Burden of Disease Study. (2018). The Lancet Planetary Health. [online] Available at:
  • [13] WHO (2019). Cardiovascular diseases. [online] Available at:


Medium is an open platform where 170 million readers come to find insightful and dynamic thinking. Here, expert and undiscovered voices alike dive into the heart of any topic and bring new ideas to the surface. Learn more

Follow the writers, publications, and topics that matter to you, and you’ll see them on your homepage and in your inbox. Explore

If you have a story to tell, knowledge to share, or a perspective to offer — welcome home. It’s easy and free to post your thinking on any topic. Write on Medium

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store