Killer in the air6 min read . Updated: 17 Nov 2014, 07:26 PM IST
Air pollution is not just hurting your breathing, causing asthma and making you wheeze, it's also affecting your heart and weight
In September, an interesting case study of a woman suffering from asthma was published in the journal Annals Of Allergy, Asthma And Immunology. The woman had moved recently from a rural community to a dense urban environment in the US. Though she was asthmatic, she enjoyed biking to work, and her new route took her through a lot of traffic. Her doctor analysed her bike route, found that 70% of her commute was in close proximity to major roadways and recommended an alternative route where only 15% of her time would be near high-traffic roads.
She followed the new route over the next month and her asthma improved.
An October study published in the British Medical Journal showed that exposure to vehicular pollution during pregnancy can damage the child’s lungs. Another study presented earlier this year at the American Thoracic Society International Conference stated that exposure to air pollution during the second trimester of pregnancy could lead to an increased asthma risk in children. “Yes, that’s how potent the pollutants in the air we breathe all the time are. And that’s how strongly they affect our respiratory health. At rest, we breathe approximately 12-15 times per minute. That’s a lot of air that goes in—air which if polluted can cause huge damage inside," says Arvind C. Kacker, senior consultant, Delhi ENT Hospital.
In India, the situation is rather dismal. Check the air quality forecast on the Indian Institute of Tropical Meteorology website run by the Union ministry of earth sciences (http://safar.tropmet.res.in/) and it’s clear how bad pollution levels in the Capital are. Levels of PM2.5—the tiny particulate matter that causes the most damage to human health—are among the highest in the world, and PM10 levels, a measure of larger particles, are even worse.
The website doesn’t post for other cities, but L.M. Parashar, senior ENT specialist, Nova Specialty Hospitals, New Delhi, says that just breathing in in any metro tells you that the air feels thick because it is heavy with debris and pollution.
The World Health Organization (WHO) has already issued an alarm about how bad the air quality is in India and China. “In many cities (the Capital included) it also leaves a chemical taste and grime on the skin, another indicator of pollution levels. Many of my patients become all right when they leave New Delhi and their symptoms (like breathing troubles, asthma, etc.) reappear when they re-enter the city limits," adds Dr Parashar.
“It is commonly seen in our practice that children growing up in areas with higher levels of pollution will have lower levels of lung function and a higher risk of developing symptoms such as cough and bronchitis. But increasingly adults too are getting affected. PM2.5 is particularly dangerous as the particles can travel deep into the lungs, causing serious respiratory problems. And in cities these are caused mainly by car exhaust. With temperatures dropping now, pollution caused by millions of cars is getting trapped in the air, worsening the situation," explains Dr Kacker.
New research in Europe has shown a clear link between higher levels of exposure to air pollution and deteriorating lung health in adults. The European Study Of Cohorts Of Air Pollution Effects (ESCAPE), published online in the European Respiratory Journal in September, saw researchers collecting lung function data from 7,613 participants through spirometry testing in adults across eight countries—Switzerland, France, Germany, Italy, Belgium, Spain, Sweden and the UK. “Although the levels we see in Europe are much lower than in the megacities in China and India, we are still seeing a deterioration of lung function in people exposed to higher levels of air pollution, and this must be addressed," wrote the researchers.
According to WHO’s Ambient (outdoor) Air Pollution In Cities Database 2014, which contains the concentration of fine particulate matter—PM10 and PM2.5—from almost 1,600 cities in 91 countries, the world’s average PM10 levels by region range from 26-208 ug/m3, with a world average of 71 ug/m3. In Delhi, the figure is usually upwards of 350. WHO says that the lower the concentration of fine particulate matter, the better it is for human health.
An attack on your heart
“For decades, research on the health effects of air pollution has focused on the lungs, where the effects are most noticeable. But now reports are coming in on how these carbon particles are equally bad for the rest of our body," says Arvind Patil, consultant, internal medicine, Columbia Asia Hospital, Pune.
According to a recent study published in the Journal Of Occupational And Environmental Medicine, exposure to outdoor air pollution can increase the risk of cardiac arrest. The researchers studied 559 patients with out-of-hospital cardiac arrest in Okayama City, Japan, between 2006-10 and reported that particulate matter and ozone may induce cardiac arrest via two distinct pathways. “Exposure to particulate pollution may result in myocardial in-farction (heart attack), while ozone may worsen other cardiac conditions, increasing the risk of cardiac arrest," they write. They found that 48-72 hours after days with high levels of particulate air pollution, the risk of out-of-hospital cardiac arrest increased by 17%, and there was a 40% increase in risk 72-96 hours after days with higher ozone levels.
Another study published in March in the American Journal Of Respiratory And Critical Care Medicine reported evidence supporting a connection between traffic-related air pollution and cardiovascular disease. The researchers found an association between exposure to high levels of traffic-related air pollution, with changes in the right ventricle of the heart that may contribute to heart disease.
“Yes, it has been observed that constant exposure to polluted air can lead to persistent narrowing of smaller airways in the heart, causing increase in the blood pressure in the pulmonary (lung) arteries which, if chronic, can increase pressure in the right side of the heart and lead to congestive heart failure," says Dr Patil.
There is a possibility that your excess weight could be due to your city’s pollution level. A September study in the Journal Of Occupational And Environmental Medicine indicates an association between exposure to black carbon—a measure of fine-particle air pollution from traffic sources—and leptin levels. The researchers studied 765 older adults in Boston, US, and found that average leptin levels were 27% higher for older adults in the highest category of black-carbon exposure.
“Leptin, also known as the satiety hormone, regulates the amount of fat stored in the body. It is involved in the regulation of energy intake and expenditure, and plays a key role in the regulation of appetite, food intake and metabolism. Levels of leptin are directly associated with total fat amounts in the body and higher levels are thus related to obesity, and even diabetes," explains Dr Patil.
SAVE YOUR LUNGS
According to Arvind C. Kacker, moving to less polluted areas may not be an option for everybody but there are small things you can do to lower the impact of air pollution:
®Living in crowded areas makes you more susceptible to the ill-effects of pollution. Find ways to increase exposure to open, green spaces; take vacations, go sit in the park for some time every day, consider shifting to a greener locality if possible
u Avoid exercising or going for walks in high-traffic areas, and opt for green spaces or indoors, like shopping malls
u Roll up your car windows at traffic intersections at peak hours to avoid pollution
u Keep your weight in check. Overweight or obese adults breathe 7-50% more air per day than an adult with healthy weight, making them more vulnerable to air contaminants
u Have an immunity-boosting diet such as foods high in antioxidants (oats, yogurt, nuts, fish, citrus fruits and green vegetables)
u Avoid areas in the neighbourhood where rubbish is burnt. The heat from the smoke can burn the tiny bronchioles in your lungs and some of the chemicals in the smoke can be poisonous
u Try to avoid toxic fumes. If you can’t, breathe in through your nose, especially around toxic fumes (like car exhaust, etc). The hair in your nose acts as a filter and only lets extremely fine particles through, keeping the rest and combining it with mucus. Also, try to take shallow breaths so that the particles don’t go deep into your lungs. Later, cough to force them out.