Clearing the air

Air pollution is suddenly the topic of living room debates and Facebook fights. Here's what you need to know to breathe easier ... or at least score a few debating points

Last month, there was Delhi’s famous and infamous odd/even scheme of rationing cars on roads. Then, last week, along came Mumbai’s garbage dump fire, “visible from space”. These two events, and the media coverage around them, have turned the topic of air pollution into the stuff of living room debates and Facebook and Twitter fights. Everybody has an opinion on air pollution now, or is rapidly acquiring one. We bring you this cheat-sheet to help you sound knowledgeable on the topic du jour.

First of all, how big does something have to be to be visible from space Depending on the quality of its equipment, a satellite could easily see your car from space, even if it’s a Nano. Military satellites are capable of viewing smaller objects, but the military doesn’t tell everyone exactly what they can see from space. So a big fire being "visible from space" No big deal. Any biggish fire would be visible from space. That said, the fire in Deonar, Mumbai, did push the city’s air quality index down. PM 2.5 levels shot up.

What is the air quality index And what’s PM 2.5 Air quality index is a measure of the quantity of different pollutants in air. Air is a complex mix of a lot of things. Out of these, air quality indices typically measure pollutants in the form of particulate matter, in two sizes — 10 microns and below, and 2.5 microns and below — and the gases carbon monoxide, ozone and nitrogen dioxide. The particulate matter below 2.5 microns is called PM 2.5.

If more of these gases and particles show up in the AQI measurements, the numbers shoot up, and that’s a cue for all of us to start worrying about choking on the air we breathe.

Where do these pollutants come from Some of it comes from natural sources. Even the cleanest air has carbon monoxide, nitrogen dioxide and ozone. A lot of the particulate matter globally is dust and sea spray. Volcanic eruptions and forest fires also contribute to the global air pollution. Even the really small particulate matter, PM 2.5, includes viruses, which are from perfectly natural sources, and can be pretty damaging to human health.

Human contributions to air pollution come from a wide range of sources. The generation of electricity in thermal power plants is one major source. Vehicles that move by burning fossil fuels are another. Apart from these two, a surprising amount of the air pollutants can come from adding up of many small kitchen fires and the burning of garbage and leaves.

For the earth as a whole, the bulk of aerosols — the tiny particles and droplets afloat in the air — come from natural sources. According to NASA’s Earth Observatory, globally, around 90 per cent of aerosols by mass have natural origins. How much any given source, natural or artificial, contributes to the air pollution varies from place to place, and time to time. How does air pollution vary with place and time Easy. The closer you are to a source of pollution, the more its impact is likely to be. So if you happen to live in the Sahara Desert, or the Thar desert, your big problem would be dust. Some of the dust particles can be small enough to qualify as PM 10. Volcanoes and forest fires usually don’t have human habitations around them, so those don’t affect human beings too much, though the volcanic eruptions can release massive amounts of pollutants into the air in very short time.

Sea spray is a big part of aerosols as a whole, simply because 71 per cent of the earth’s surface is covered by oceans. Obviously, it’s places near the sea that get sea salt spray in the air.

The “anthropogenic” or human-caused pollution can also be of different kinds. If you live near a thermal power plant, that’s going to be the big factor. Places near industries have smokestacks ruining their air. The neighbourhoods of big garbage dumps are affected by that. Areas with heavy traffic see vehicular pollution as the big factor.

The pattern also changes with the season, weather, and the time of day.

“The increase and decrease in air pollution is based on many factors with wind being one of the major factors. In Mumbai, places that are closer to the sea and have a better green cover like Colaba, where the flow of wind is much better, have less air pollution than places that are land-locked and have a lower green cover, such as Sion. Air monitoring at these places since the past few years has shown Sion to have a higher level of air pollution than at Colaba,” says Dr Rakesh Kumar, Director of the Mumbai office of National Environmental Engineering Research Institute (NEERI).

“Pollution levels in winter are higher as the flow of wind is much slower than in the summer or monsoon”, he adds.

However, even within a certain area at a certain time, not everyone is going to have the same exposure to air pollution. How much of polluted air a person breathes depends on a lot of other things as well.

Such as Such as your job, for instance. If your work involves spending a lot of time outdoors, or in traffic, you’ll be inhaling a lot more of the outdoor air. Construction workers, traffic policemen, and drivers are among those who end up breathing a lot of polluted outdoor air — especially because they have to be at hotspots of different types of pollution.

If your work is indoors, chances are you spend the bulk of your time inside an office building or at home. People working in air-conditioned offices therefore have lower exposure to outdoor air. Women and children generally tend to have more exposure to indoor rather than outdoor air. Indoor air is usually qualitatively different from outdoor air.

Okay, how different Again, depends. It varies with the kind of house you live in, which floor, and whether you use air conditioning or not. It also depends on what kind of fuel you burn in your kitchen, whether you smoke indoors, whether you use mosquito coils or other mosquito repellents.

“Everyone in a city gets affected by air pollution regardless of where they live. A person living in an air-conditioned environment also gets affected by air pollution but the severity is much lower for them than those who live in a non-air-conditioned environment,” says NEERI’s Dr Kumar.

Indoor air is not necessarily better than outdoor air, though. It can often be worse.

According to the World Health Organisation (WHO), “Globally, 4.3 million deaths were attributable to household air pollution in 2012, almost all in low and middle income countries.”

The WHO reckoned that, “Around 3 billion people still cook and heat their homes using solid fuels (i.e. wood, crop wastes, charcoal, coal and dung) in open fires and leaky stoves. Most are poor, and live in low- and middle-income countries.” 3 billion people is more than 40 per cent of the world’s population.

Even those who use healthier fuels but use mosquito coils would have poor indoor air quality. A single mosquito coil generates as much PM 2.5 as 75-137 cigarettes, according to a report on indoor air pollution by the World Health Organisation.

I don’t use solid fuels or mosquito coils, but I live in a city and drive a car. Should I be worried about air pollution or not Yes, you should be worried, since many cities in India are badly polluted, and outdoor air pollution is harmful. Delhi and Mumbai are not the worst cases. Ahmedabad, Bengaluru, Gwalior, Patna, Lucknow, Kanpur, Varanasi, Muzzaffarpur and Raipur are among cities that have reported worse air than Delhi in the past. Mumbai air is generally much cleaner than Delhi's, but still ranks as moderate or poor rather than satisfactory.

So worry, but try to keep a sense of perspective. The first thing is to figure out your own exposure to air pollution. Check the indoor bit first, because it’s the bit that is in your hands — you can do something about it by yourself.

An air-conditioned environment may decrease exposure to outdoor air pollution, but generates its own problems. ACs often become breeding grounds for bacteria and fungi, which get blown into the room. Air-conditioning also sucks the humidity out of the air, which has a side-effect — it dries up the lining of the nostrils in which microbes get trapped on their way in. Susceptibility to respiratory infections increases. Therefore, if you use an AC, ensure it is clean and well-maintained, and keep yourself properly hydrated.

Rishi Agarwal, an environmentalist from Observer Research Foundation, said that inhaling of stale air also affects breathing. “The dust that gathers keeps circulating in closed rooms. Volatile organic compounds from building materials and furnishings, such as new carpets or furniture, also increase indoor air pollution. The adhesives used in furniture often start evaporating with a change in temperature and begin circulating in rooms. When a person continuously inhales it, it certainly affects them,” he says.

What can happen because of breathing polluted air What diseases can I get Mainly respiratory diseases. According to medical experts, bronchitis, asthma, and obstructive lung disease are the main types of respiratory diseases. “In the past 10 years, the incidence of respiratory infection cases has doubled not only in Mumbai but across the country. There are two types of respiratory tract infections — upper and lower. However the latter has a more deadly effect on the health of people,” says Dr Altaf Patel, director of Medicine at Jaslok Hospital and Research Centre in Mumbai.

Upper respiratory tract infections are mainly from viral causes and include influenza, whooping cough, and sinuses. Lower respiratory tract infections include bronchitis, asthma, and pneumonia.

Bronchitis is caused by viral or bacterial infection. But smoking, air pollution and dust or toxic gases in the environment can aggravate it. “Higher level of pollutants in the air worsens the condition of people with pre-existing lung diseases like bronchitis, asthma and others. And if the person is also a cigarette smoker than the joint effect further aggravates the condition,” says Dr Prashant Chhajed, pulmonologist at the SL Raheja Fortis Hospital in Mumbai.

The total number of cases of respiratory ailments is on the rise for both men and women, but the rise is sharper for women. Medical experts blame a rise in the smoking habit among women for this. “Previously, respiratory problems were mostly limited to men but now with a rising habit of smoking among women, they are equally falling prey to these problems. This is also one of the main reasons for growing lung cancer cases among women,” says Dr Kirti Chadha, Divisional Head of Oncology at Metropolis Healthcare Ltd, Mumbai.

Oddly, Kerala — more famous for its beaches and backwaters than for polluted air — had by far the maximum reported cases of acute respiratory infections in India, according to national figures for 2014.

What about cancer Does air pollution cause cancer Air pollution can contribute to causing cancer. The International Agency for Research on Cancer, the apex global body on cancer research, lists 118 agents as carcinogenic. Some air pollutants are listed in this lot, along with tobacco smoking, alcohol, processed meats, salted fish (Chinese style), the Hepatitis B and C viruses, and areca and betel nuts. “Zarda paan” is definitely carcinogenic. So is paan masala. The most common cancers in India are oral cancer among men,and cervical cancer in women.

Cancer is caused by changes in the DNA of the cells of a part of the body. The cause may be hereditary, but environmental factors can trigger it. Environmental factors include lifestyle factors and medication, apart from exposure to pollutants. For instance, estrogen postmenopausal therapy is in the list of known carcinogens.

So what’s the bottomline Air pollution from anthropogenic sources is a real and serious problem, and needs to be tackled. The pollution aspect apart, there’s also the related aspect of climate change. Therefore, serious changes in processes and systems, apart from lifestyles, are called for — not dramatic gestures such as odd/even.

As for things in the air killing you ... well, smoking and drinking are killing you too. So is eating processed meats. And as already mentioned, an unhealthy “microenvironment” at home or in office may be killing you more than the air outside. If you take your health very seriously, there’s plenty you can do to improve your odds of living longer, before you get to moving out of the city in search of clean air.

With inputs from Rupsa Chakraborty and K.A. Dodhiya