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Killing me softly...

Roberta Flack's chartbuster in the seventies has a new meaning for healthcare professionals. They are seeing how our day to day routines are killing us. The food we eat, the air we breathe, how we move, and our social interactions are killing us softly… without a song.

Many of these factors can be controlled by us on a personal level to a large extent, but there is one that can’t – air pollution. Managing air pollution requires a collective effort of individuals, communities, industry, and governments. The contribution and importance of each of these cannot be ignored. The benefit of the collective effort will be reaped immediately, and by generations to follow.

7 million people die annually because of air pollution across the world. Almost half of these are not because of respiratory or lung problems, but due to cardiovascular disease. Also, the impact of air pollution on vulnerable groups - growing children and the elderly - leads to much higher morbidity and mortality in these groups.

What is air pollution?

Air pollution is a complex mixture that includes

  • Particulate matter (PM)

  • Ozone

  • Carbon monoxide

  • Sulphur oxides

  • Nitrogen oxides

  • Methane and other gases

  • Volatile organic compounds (e.g., benzene, toluene, and xylene)

  • Metals (e.g., lead, manganese, vanadium, iron).

PM is further classified according to size -

  • PM10, <10 μm

  • PM2.5 < 2.5 μm

  • ultrafine (UF), PM0.1, < 0.1 μm

The impact of the PM depends on the level it can penetrate after breathing. Apart from size, ventilation and airflow also has an impact on the level of penetration.

Indoor vs Outdoor pollution

Outdoor and indoor air are different in many ways. While outdoor air has fossil fuel derivatives, many industrial effluents, heavy metals and volatile organic compounds, indoor air has more viruses, bacteria, fungi, mites etc

The most prevalent biological agents include viruses, bacteria, fungi, algae, amoebae, pollen grains, mites, insects, and human and animal dander. Homes may also contain non-biological substances, such as respirable particles (environmental tobacco smoke and combustion products), CO, CO2, NO, NO2, radon, formaldehyde, volatile and semi-volatile organic compounds, and asbestos, any of which may cause or worsen certain respiratory symptoms. Volatile organic compounds from paints, emissions from wood and furniture, sprays, household cleaners, disinfectants, furniture, printers are some of the sources of indoor pollution.

Closed windows and doors may trap the pollutants and make the indoor air quality worse than outdoors. Smoking, poorly ventilated kitchens, air fresheners and even mosquito coils/ incense can further contribute to indoor pollution.

Some of the additional challenges in semi-urban and rural areas are the use of fossil fuel for cooking, high tobacco usage and excessive dust.

Impact of air pollution

Air pollution affects multiple organs and systems of the body, not just the lungs. The lungs are our body’s filtration system for air. The protective mechanisms of the body, right from the nasal passages down to the alveoli (the air sacs where the gaseous exchange takes place) is penetrated by different sizes of PM, ranging from ultrafine to PM10. PM2.5 reaches the deepest parts of the lungs- the alveoli, whereas Ultrafine particles can be absorbed in the blood and cause damage to blood vessels, heart, and other organs.

Once entrapped these particles cause damage in multiple ways. For PM2.5 the damage occurs at levels of 40-100 μg/m3.

The local reaction of these foreign bodies causes inflammation stimulating inflammatory cytokines. The very protective mechanisms we have ultimately cause inflammation in the rest of the body as they spill over into the blood and reach other parts including heart and brain.

Pregnancy is also a phase of low immunity for the mother. Combined with the fact that the foetus is rapidly growing, exposure to pollution at this time has major impact both on the mother and baby. These babies have higher risk of autism and lower IQ apart from the impact on heart disease, higher incidence of diabetes, weight gain and the long-term consequences of these conditions.

Children are in a rapidly growing stage and are more vulnerable to the damage. They have higher respiratory rate, and they also tend to spend longer time playing outdoors. This leads to a six to eight fold increase in the airflow to lungs. Early life exposure predisposes them to Asthma, recurrent respiratory infections, higher incidence of lung cancer, high blood pressure, diabetes, weight gain and metabolic disorders. Cholesterol deposits begin in adolescence but have been observed in children exposed to air pollution at age as young as 3 years. The impact on the brain can lead to autism and the incidence of diabetes Type 1 is higher in these children if they have been exposed in utero or early childhood. Psychological impact has also been observed on children. A study in Taiwan found negative impact on the Happiness score in adolescents.

The elderly is another vulnerable group, with women above 60 years being affected the most. This age group already has some of the risk factors and lower immunity. Exposure to air pollution makes them more prone to not only heart attacks, but Atrial fibrillation, other rhythm disorders and strokes. Long term exposure also increases the odds of getting Dementia, Confusion and Parkinson’s disease.

Air Pollution also causes eye irritation and conjunctivitis and skin problems in some people with sensitive skin. Nonspecific symptoms like headache and fatigue are also commonly seen with poor Air quality.

Source-Enhancing indoor air quality –The air filter advantage

The Solution

The long-term solutions to the harmful effects air pollution cannot be found at individual level, but there are a few individual Lifestyle strategies which have been explored.


  • Although, the research on the impact of diet on effects of Air pollution in still not conclusive, there is some evidence of the beneficial effect of Mediterranean diet. This means having whole grains, fibre, higher intake of vegetables which give antioxidants, mostly vegetarian proteins and fat-predominantly from mono-unsaturated (MUFA) and omega-3 PUFA. This diet has also been proven good for heart and brain health.

  • Other foods which may have a beneficial effect directly or indirectly through their antioxidant activity and by improving immunity are:

    • Vitamin C rich foods like citrus fruits, Amla (Indian gooseberry), Kiwi, peppers, potatoes etc

    • Curcumin with piperine (from Turmeric and black pepper)

    • Omega 3 fatty acids found in Flaxseeds, walnuts, pumpkin seeds, chia seeds.

To exercise or not to exercise

Exercise is a very vital part of our lifestyle. Exercising and being physically active had far reaching effects on our health. During exercise breathing rate increases and as the intensity increases there is a tendency to breathe from the mouth. This bypasses the filtration process in the nasal passages. Exercising in these circumstances causes more exposure to pollutants.

However, not exercising is not an option. The benefits of exercising far outweigh the impact of air pollution. A few precautions to be taken are-

  • Avoid high pollution areas like major roads and instead exercise in green spaces.

  • Avoid exercising outdoors during rush hour. Instead exercise outdoors at times when pollution levels are lower- afternoons and early evening.

Exercising indoors may not be safe too, take care to reduce indoor air pollution and do low intensity exercises preferably. Air quality in Gyms needs to be monitored too.

Missing Exercise is not an option, but be careful in minimising risk by choosing the right time and place.

Air purifiers

Air purifiers can decease particulate matter and improve air quality. There are a few caveats though-

  • They should have an efficient HEPA filter

  • The HEPA filter and other filters tend to get clogged very easily and need to be cleaned and replaced frequently.

  • Filters do not work beyond PM, like on benzene, formaldehyde, heavy metals, tobacco smoke and many other pollutants. So, airing and minimising the sources of these have to be actively done.

There has been some research on air purifying plants, the initial study being done from NASA. Plants like Areca palm, Gerbera daisy, Chrysanthemum, Sansevieria and Dracaena decrease the levels of some of these. Put them in ample numbers in living spaces, but not in bedroom (Sansevieria is the only exception which can be put inside the bedroom).

However, the impact of air purifiers and plants need further research, specially at high levels of pollution. The best solution must be cohesively worked upon by all the stakeholders, in minimising the emissions and looking for eco-friendly alternatives.

Air pollution is one of the most important factors contributing to Disability adjusted life years (DALY’s) - 26% of the burden in the India and “killing us softly” (and slowly) by shortening the lifespan of people living in high pollution regions by 1.7 to 3.5 years.


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