You Are What You Breathe
The health effects of air pollution are many and it seems like every day bring more. There has been a surprising amount of pollution-related health news in the last few weeks. Here's a snapshot.
Food dominates our lives so much. And it’s understandable. It brings joy to some, satiation or anguish to others, and livelihood to many; it’s often the centrepiece of celebration and culture.
‘You Are What You Eat’ is a popular Netflix documentary on a long-running experiment on twins following different diets. It’s a fascinating and entertaining watch on the effect of food on our health. But why isn’t there such widespread obsession for another thing we consume copiously - air? There’s enough science to show that breathing polluted air profoundly affects our lives, even in moderately polluted places, arguably far more than food.
For years research papers have been piling up establishing how air pollution affects humans, particularly the more vulnerable especially children, the elderly, and the unwell. In the past few weeks, more developments and papers have made it abundantly clear that you are what you breathe.
Consider this. Here’s how every increase of just 10 micrograms per cubic metre of PM2.5 increases the risk of deadly diseases: Heart attack by 13%, stroke 16%, hypertension 17%, COPD or Chronic Obstructive Pulmonary Disease (essentially chronic lung disease) 16%, asthma in children by as much as 34%, Type 2 diabetes10%, dementia by a steep 46%, and lung cancer 16%.
‘Every day we discover a different outcome related to air pollution.’
These are just some of the life-altering harmful effects of air pollution. Dr Francesco Forastiere, of Imperial College, London, who in a recent WHO webinar listed the high risk of non-communicable diseases because of exposure to air pollution and PM 2.5, in particular, said, “Every day we discover a different outcome related to air pollution.”
Delhi’s PM 2.5 annual average has been about 100 micrograms, give or take, for the last five years. Forastiere explained, in an email response to my questions, that for such places there aren’t enough studies yet.
The greater the pollution, the higher the impact?
Forastiere says, “The per cent increases in risk I presented are for exposure levels that have been studied in epidemiological investigations, ranging from 5 to 30 maximum 50 ug/m3…. Unfortunately, we do not have enough studies for these concentration ranges (> 100 micrograms) to be able to precisely predict the risk and our analyses are usually underestimation of the impacts.”
However, Dr Poornima Prabhakaran, Director, Centre for Health Analytics Research and Trends, Ashoka University, highlights that there are some India-specific studies. Recent ones conducted in Delhi and Chennai show how cholesterol levels and diabetes risks rise as pollution rises.
India-specific studies are being conducted here given the high air pollution levels. Most evidence is based on studies from low-pollution settings in other parts of the world or cross-sectional studies. In India the burden of non-communicable diseases is high. A recent study done in Delhi and Chennai shows that just a relatively small change of 10 microgram/cubic metres in the monthly exposure to PM2.5 increases the risk of Type 2 diabetes. The authors say, “Our results suggest a link between long-term exposure to ambient PM2.5 and T2DM (Type 2 diabetes), which may have potential public health significance as well as policy implications for India, a country with high levels of ambient pollution as well as high burden of cardiovascular and cardiometabolic diseases.”
“We observed increased risk for developing diabetes in both cities against long-term exposure to PM2.5, although the largest effects were observed against 2 years and 1.5 years in Chennai and Delhi, respectively.”
Source: PM2.5 exposure, glycemic markers and incidence of type 2 diabetes in two large Indian cities
Another study currently underway is looking at how clean air and the use of clean fuel like LPG (i.e. cleaner than burning solid biomass) benefit pregnant mothers by lowering the chance of low birth weight. A preliminary version of the report indicated that in a “highly polluted” place, where the PM 2.5 is above 93 micrograms/m3) the benefit is lost.
The fascination with ‘you are what you eat’ has spawned a massive industry around food fads and fixes. What will it take for the same to happen with ‘you are what you breathe’? In a sobering reminder, air pollution is hardly an election issue currently in one of the world’s most polluted countries and the largest democracy.
How air pollution impacts health and productivity - Links to a few recent reports
Explained - air pollution and health impact on children.
Source: State of Global Air’s Cleaner Air, Healthier Children video, Health Effects Institute, US.
Air pollution and diabetes: Study shows worrying link between PM2.5 and Type 2 Diabetes in Delhi, Chennai.
Air pollution and cholesterol - Delhi and Chennai study reveals a link between high PM 2.5 and lipid levels.
Vehicle fumes cause asthma in kids, and premature deaths in the elderly - 2040 projection by ICCT which exposed Volkswagen’s dieselgate scandal.
How air pollution impacts the economy - an ex-PM, an ex-WHO chief scientist and other influential scientists, researchers, health officials, finance and policy experts join hands Our Common Air.
On climate justice, two court verdicts in India and Switzerland could have far-reaching impacts.
Why and how India’s main air pollution strategy, NCAP or national clean air programme, needs to be overhauled - CEEW researchers on NCAP 2.0.
Air pollution and strokes: Research finds exposure to air pollution can lead to increased stroke risk within five days (a 2023 report).
Air pollution impact on cognitive development effect on examination results.
Air pollution impact on skin - earlier reports from India and the US.
“No politician around the world can say I did not know.”
Dr Maria Neira, WHO Director, Public Health, explained there’s enough strong health evidence to step up action against air pollution.