There is mounting evidence that the air quality in Pakistan is having a strong impact on our quality of life. While research has shown the impact of poor air quality on morbidity and mortality for more serious conditions, its insidious effects are not discussed enough.

The numbers paint a frightening picture.

According to the World Air Quality report, Pakistan was the second most polluted country in 2018. At the time of writing this article, Karachi and Lahore were among the 10 cities in the world to have the most polluted air, with Lahore's AQI (Air Quality Index) at 188 and Karachi's at 182.

An AQI of up to 50 is healthy. Beyond that, an AQI 0f 100-150 becomes unhealthy for children, and people with heart and lung disease. An AQI of above 150 is unhealthy for everyone while levels above 300 constitute a health emergency.

Data from Lahore and Peshawar showed an AQI of above 300 on multiple days in the month of November. As for Lahore alone, in November, there wasn't a single day in the country's cultural capital that could be called healthy.

Pakistan’s air pollution levels have transformed into a more dire health emergency than smoking, tuberculosis, and unsafe water and sanitation, reducing our life expectancy more than any of the three listed causes.

In this situation, children are especially vulnerable, and air pollution causes 1 in 10 deaths for children under the age of five. Air pollution worsens respiratory problems for children as well as adults, causes childhood cancer, and impacts healthy brain development. For pregnant women, being exposed to air pollution can lead to premature births.

In this article, we as a group of public health experts will attempt to comment on the various insidious effects that air pollution has on the public at large.

How respiratory health is impacted

Air pollutants come in all shapes and sizes (literally, ranging from coarse to ultra-fine) depending on the source of the pollutant. Studies show that air pollutants contain chemical substances that cause direct damage to the lungs' inner lining and prevent DNA repair of an already damaged inner lining. This imbalance in damage and repair can promote abnormal cell growth, leading to lung cancer.

Moreover, research shows that the presence of air pollutants in our airways paralyses the cilia (small hair-like structure on our wind-pipes that clear any bacteria or foreign particles), causing an increase in bacterial growth, thus promoting infections like pneumonia.

Unfortunately, the very medium of this pollution has exposed us to it every day, involuntarily allowing them to enter our bodies through every breath we take. The very nature of this exposure primarily affects our lungs, the gateway to air inside our body, leading to asthma, chronic obstructive lung disease and of course lung cancer.

Also read: The poisonous cocktail of smog and how we're paying the price

Recent estimations by the World Health Organisation show that air pollution was responsible for almost 10 million deaths in 2018. Overall, up to 35% of total deaths occur due to lung related diseases, caused directly or indirectly by air pollution, making it the world’s largest health risk.

In Pakistan, there are many more sources of air pollution other than motorised vehicles and industries. A vast majority of the population in Pakistan depends on solid fuel burning for basic needs like cooking, heating and light which further increases the risk of air pollution exposure within homes, and especially to children. Such exposure can reduce a person’s ability to combat diseases, especially lung-related infections like tuberculosis.

Effects on cardiovascular health

Population scientists over the years have examined outcomes of people exposed to high levels of air pollutants and have found strong independent association of exposure to ambient air pollutants with development and progression of cardiovascular disease and risk factors. These include diabetes, high blood pressure, increased risk of heart attacks, strokes and aortic dissections. Leading medical journals like the New England Journal of Medicine, The Lancet and Circulation have published papers linking exposure to particulate matter with higher risk of development of heart disease, premature death and poorer quality of life after a heart attack.

In the context of Pakistan, it is critical to realise the magnitude of the difference in air quality between countries where these studies were done and air quality in Pakistan.

The air pollutant that is associated with adverse cardiovascular health outcomes is termed Particulate Matter 2.5 or PM2.5 because of its size (< 2.5 µm). Unlike the larger air pollutants, PM2.5 makes its way all the way down to the lungs and gets absorbed in the blood. Hence, it has systemic and long-lasting effects. These effects include inflammation, endothelial dysfunction and activation of thrombotic pathways, all of which increase the plaque burden in the arteries of the heart contributing to the risk of heart attacks and heart failure.

By conservative estimates, every 10 µm/m3 increase in PM2.5 concentration is associated with a 10% higher risk of death in vulnerable populations, including patients after a heart attack and other heart disorders. Let us explain. For example, if someone with heart disease lives in an area where average PM2.5 concentration is 15µm/m3 and then moves to an area where average concentration is 25µm/m3, his/her risk of premature death increases by10%. These estimates are based on population studies done in western countries where the concentration of PM2.5 ranges around 5-30µg/m3. In Pakistan, the average daily concentration approaches to over a 100 µg/m3 in urban areas such as Lahore and Karachi. We do not even know what the dose response curve is like for such high concentrations of PM2.5. In simpler words, the effects of exposure of PM2.5 on cardiovascular outcomes have not been extensively studied at concentrations that Pakistanis living in urban centres like Karachi and Lahore are exposed to.

However, it is well-known at concentrations below 50 µm/m3, and the higher the exposure to PM2.5, higher the risk of heart attack, stroke, and death. Whether this exposure/risk relationship plateaus at even higher concentrations is not well understood. In the worst case scenario, the risk would go up incrementally and in the best case scenario, the risk may remain the same. Though even in the best case situation, the risk is very high and in any western country, this high level of PM2.5 would have been unacceptable.

For Pakistan, we know that high levels of air pollutants have toxic effects for our citizens. We also know that we do not completely understand the scope of the adverse health effects of such high concentrations of air pollutants. But we do not know the unknown population level effects of chronic exposure to these levels of pollution.

In the above concept diagram, we attempt to illustrate the incremental risk of death in patients with heart disease, with higher exposures to PM2.5. What this curve looks like at PM2.5 concentrations that are common in Pakistan is not known. This is indeed a crisis. The threat to public health and well-being is real and cannot be under-estimated. But finding a solution to this will be a complex process and will involve thinking along long-term policies to limit emissions as well as short-term guidelines for citizens on methods they can employ to protect themselves.

The damage to mental health

Air pollution has also been reported to have deleterious impacts on the mental health of those exposed to it. Particulate matter in the atmosphere can get absorbed into the bloodstream and interfere with the functioning of our brain and the nervous system. This can include impairment when it comes to concentration, memory problems, and difficulty in emotional regulation, eventually leading to decreased productivity of the workforce and causing the national exchequer to lose billions of rupees annually.

Mental health professionals working in Pakistan have also observed an increased rate of relapse in patients affected by mental illness with the change of weather and air quality. While some may attribute it to the cold, it is highly likely that increased air pollution during winter may be leading to increased risk of relapse in patients affected by mental health problems. While we need more data to support this proposition, there have been sufficient anecdotal accounts by mental health professionals reporting an increased rate of relapse in patients living in more polluted parts of Karachi during the winter season.

Air pollution is especially bad for children’s mental health, since not only are children more exposed to its effects (due to a higher rate of breathing and more intake of pollutants) but the developing brain is more susceptible to harmful pollutants.

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This can have a long-term adverse impact on children’s ability to excel in education, form healthy relationships, and ultimately become productive members of society. Research has also shown that certain pollutants, such as lead, when inhaled by children can lead to a decrease in their IQ levels, decreased inhibition and increased violence in communities. Hence, air pollution is not just a health problem, but it can very easily turn into a much bigger societal, if not a security problem.

Pediatrics & early childhood development

In South Asia, it is estimated that approximately 12 million children are at risk because of air pollution. Previously it was thought that pollution only affects children because of respiratory compromise, but it is now clear that the respiratory component directly affects the neuro-development element because children respire more air per unit due to their surface area.

When air toxicity is at the level which Pakistan is currently experiencing, it is safe to assume that children will end up breathing in more toxic air. The toxic air that is breathed in directly compromises the neural connections that are made in the most important time of development: the first 1,000 days of life. Neural connections are affected because nano-particles can directly impede the blood-brain barrier and in turn can stimulate the brain to produce free radicals which damage the brain itself. These damages are not limited to just the structural component, but also affect brain functionality by damaging the white matter which is an important neural connection that regulates our body.

The blood-brain barrier keeps the blood from flowing into our brain — it’s like a filter mechanism that keeps excessive fluid and other substances potentially toxic for the brain from getting into it. Free radicals are ions that can cause oxidative damage to body parts, in this case the brain. So when the blood brain barrier is weakened, the brain receives more oxidative damage because of the free radicals.

Loss of function of the barrier and the radicals all contribute to inflammation. For an organ that is already sensitive and in its development stage, the stress alone can contribute to cognitive dysfunction, resulting in a decrease in IQ points (by approximately 4-6) which is a significant figure. Furthermore, the compounded effect of respiratory compromise due to pollution contributes to absenteeism, further limiting a child’s learning potential.

Thus, it can be hypothesised that the insidious effect of pollution further contributes to our morbidity and mortality, not just through physical disease but also with long-term damage that may contribute to early ADHD, Autism and probably Parkinson’s.

The way forward

Pakistan will have to deal with the issue of air pollution as a crisis and the country’s response will have to be multi-tiered and vary in temporality, since we need short-term, medium-term, and long-term changes. As medical practitioners, we’d leave the medium-term and long-term solutions to experts in that space, such as environmental engineers, energy professionals, and other industry experts. However, what we can urge them to do is to act now and act fast.

In the short-term, what we must propose is for citizens to take charge of their own health and well-being to the best of their abilities. Some simple measures that they must take up include purifying the air in places where they spend most of their time, such as homes and offices. Invest in air purifiers, there are many low-cost but effective local options available in the market now and the difference it will make to your feeling of well-being will be immediately noticeable. In addition, if your work involves significant time outside, then there can only be good that would come out of wearing a mask. An n95 mask would be ideal for this purpose.

This is what one can do to protect oneself and their loved ones. Now to people who can effect change, those who run industries, are in the energy sector, or work in the policy space, as physicians we urge you to consider the cost at which we are enabling economic growth. Members of our society, especially the ones who hold access to resources, must ponder the future we are building for ourselves and our children. As public health professionals, we can predict that if we continue on in the same direction, an apocalyptic future is not a dramatic hyperbole but a probable reality for the region.

Are you solving Pakistan's environmental and climate-related challenges? Share your insights with us at prism@dawn.com