Air Pollution: A Preventable Health Risk

That distinctive brownish haze settling over the city's horizon has become quite a familiar sight for most of us. The frequent sighting of smog reminds us of the harsh reality of urban life to which we have become perfectly accustomed.

We understand well that the cause of this unsightly view is due to air pollution, and it is something that we learned to accept as an inevitable by-product of the things that we very much depend on during our daily lives. At the same time, we are aware of its threat to us and the environment, and the adverse effects it causes to our health and wellbeing.

To better understand the health impacts of air pollution, it is important to first know more about it in terms of what it is and how it is caused.

Air pollution can be described as:

A contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere.

Air pollution is essentially a mixture of hazardous substances in the atmosphere caused by the emission of a number of different pollutants from a variety of sources. It can be classified as being either visible e.g. brown smog, or invisible e.g. carbon monoxide, depending on its composition.

The Environmental Protection Agency (EPA) has established national air quality standards based on measuring levels of certain pollutants in the air to create an Air Quality Index (AQI). Measuring and monitoring how clean or polluted the air is vital for public health.

The six 'criteria' air pollutants on which the AQI is based are:

Carbon Monoxide (CO).

Nitrogen Dioxide (NO2).

Ground-level Ozone (O3).

Particulate Matter (PM).

Sulfur Dioxide (SO2).

Lead (Pb).

Further to the above, there are numerous other types of pollutants that are responsible for causing air pollution, these include :

Chlorofluorocarbons (CFCs).

Volatile Organic Compounds (VOCs).

Other air pollutants e.g. Asbestos, Benzene, Kerosene and various types of hydrocarbons.

Among the numerous air pollutants that exist as mentioned previously, Particulate Matter (PM) has specifically been the subject of significant research due to it being one of the main causes of serious health concerns. PM is basically composed of both organic and inorganic material resulted from different sources of emissions, and is classified according to its aerodynamic diameter as follows:

'Coarse particles' (PM10) are 10 µm in diameter.

'Fine particles' (PM2.5) are less than 2.5 µm in diamete.

'Ultra-fine particles' (PM0.1) have a diameter of 0.1 µm.

The diameter of PM is of particular significance because it represents its capability to penetrate the bronchopulmonary system and further deep into the bodily systems. This has made PM an area of particular health concern due to its known risk of causing cardiovascular and pulmonary complications, in addition to its impact on mortality especially when associated with long-term exposure.

Causes of air pollution are numerous and vary widely, and can be a result of man-made or natural activities. The most common sources of air pollution are:

Burning of fossil fuels such as coal, oil, and gas.

Industrial activities.

Transportation.

Waste treatment.

Construction and mining operations.

Agriculture through wide use of pesticides and fertilisers.

Indoor air pollution.

Respiratory by-products of living organisms i.e. CO2.

Digestive by-products of cattle i.e. Methane.

Smoke caused by natural wildfires.

Gas emissions from volcanic eruptions.

Dust carried by wind.

Besides the massive socio-economic and financial costs of air pollution, it is considered to be one of the top environmental global threats to human health. According to the World Health Organisation (WHO), air pollution is officially linked to approximately 7 million premature deaths worldwide each year, and causes a host of debilitating health conditions - both acute and chronic.

The cause-and-effect relationship between exposure to air pollution and health disease has been formally established by a significant amount of research. Furthermore, in 2013 WHO formally recognised air pollution as having carcinogenic properties therefore labelling it as a direct cause of cancer.

The health impacts of air pollution depend on the exposure type, level and length. However, long-term exposure to air pollution is thought to have even more serious consequences compared to exposure to short-term peak pollution levels.

Exposure to air pollution happens mainly via the respiratory tract, where the pollutants are breathed in leading to a number of cellular reactions including inflammation, oxidative stress, immunosuppression, and mutagenicity. This causes widespread impact throughout the body with direct effects on major organs including the heart, lungs, brain, among many others leading to disease, and increasing risk of mortality in the long term.

Exposure to air pollution has an impact on different parts of the body, at every stage of life.

The following are some of the health conditions that have been found to have direct relation to air pollution exposure:

Cerebrovascular accidents (CVA).

Ischaemic heart disease (IHD).

Congestive heart failure.

Chronic obstructive pulmonary disease (COPD).

Lung fibrosis.

Lung cancer.

In addition to the list above, there is also strong evidence that exposure to pollutants is linked to an increased risk of developing a variety of other disorders in different bodily systems including the following:

=> Adverse pregnancy outcomes i.e. premature birth, low-birth weight, small for gestational age, fetal death, fetal anomalies.

=> Diabetes mellitus.

=> Neurodegenerative disorders and long-term cognitive disorders e.g. Alzheimer’s disease or Parkinson’s disease.

=> Other cancers due the carcinogenic effects e.g. breast cancer, leukaemia, non-hodgkin's lymphoma, etc.

=> Disorders of the immune system.

=> Reproductive system disorders.

=> Complications of certain respiratory tract infections e.g. COVID-19.

=> Neuro-behavioural disorders in children and young adults e.g. ADHD or autism.

=> Certain bone disorders e.g. osteoporosis.

Air pollution affects everyone’s health, as it is estimated that 90% of people living in urban cities are impacted by air pollution to a certain extent. However, certain groups of people are more susceptible than others i.e. children, older age groups, pregnant women, individuals with pre-existing conditions, and lower socio-economic groups.

Public policy plays a key role in reducing air pollution. However, while specific actions are being taken by governments and certain controls are being implemented to curb harmful emissions, a lot can also be done on an individual-level in terms of contributing to the overall reduction of air pollution as well as reducing exposure to air pollution. These strategies include:

Wearing face masks, preferably close-fitting N95 masks, as appropriate.

Encouraging active transport i.e. cycling or walking, instead of motorised transport i.e. public transport or car, whenever possible.

Selecting routes with open and more green spaces away from major roads and heavy traffic.

Improving vehicle standards by maintaining efficiency of vehicle filtration and ventilation systems, as well as ensuring good general maintenance of the vehicle.

Improving driving habits by closing car windows while driving in heavy traffic, keeping the ventilation on 'internal circulation' mode, avoiding rapid accelerations and decelerations, and restricting engine idling.

Planning outdoor physical exercise appropriately when the AQI is good, and avoiding conditions of high air pollution by following the local air quality forecasts.

Monitoring air pollution levels through the use of real-time information on local air quality e.g. phone applications.

Using clean household fuels for cooking and heating e.g. methane gas, electricity or solar cookers compared to the use of traditional cookstoves which burn wood for example.

Ensure good ventilation within the home, especially around cooking areas, and encourage cross-ventilation whenever possible.

Use portable air cleaners fitted with high-efficiency particulate absorbing (HEPA) filter indoors in areas of the home that are most frequented.

For individuals with pre-existing cardio-respiratory disease they must ensure optimal management of their condition through effective interventions and lifestyle optimisation e.g. maintaining a healthy weight or avoiding first/ second-hand smoke to reduce the potential risk of developing complications associated with exposure to air pollution.

Eating a healthy balanced diet rich in vitamins, anti-oxidants and nutrients can help combat the carcinogenic/ inflammatory processes associated with air pollutants.

We all need to breathe in order to survive - this simple yet crucial statement highlights the importance of air quality. As obvious as it may sound, we need to sometimes remind ourselves of the basic facts, and put things in perspective to be able to see the bigger picture more clearly.

The effects of air pollution on health have been studied for a long time, and thankfully research on air pollution and its impacts on health and the environment is progressing continuously. Having said that, unfortunately, not enough is being done to find more effective solutions for this global concern. Air pollution remains a worldwide public health risk until this day, with levels of ambient air pollutants in many parts of the world, especially where the vast majority of people live and work, exceeding the threshold for what is deemed as satisfactory air quality, resulting in devastating consequences on human health.

This is a major issue that concerns everyone regardless of their age group, their state of health or geographical location. It is for this reason that the effective management of this health risk requires the collective action of society in addition to sustained individual efforts. We must make the aim of improving air quality a priority because of our shared need to breathe cleaner and healthier air.

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