These days, a leisurely stroll through the streets of your city can actually shorten your life. The WHO recently declared Delhi to be the city with the worst air quality in the world. In late January, before American President Barack Obama’s three-day visit to India’s capital, the media was flooded with reports about how his brief exposure to Delhi’s air would reduce the life of the US President by six hours.

The same WHO report revealed that air quality in the world’s cities is consistently worsening, putting inhabitants at risk for respiratory disease, allergies and other ailments. India’s other metros aren’t an exception to this trend. At a recent conference on green housing in Bangalore, experts cited United Nations Environment Programme statistics and compared breathing the air in Bangalore to smoking six cigarettes a day. (New Delhi air, they said, is equivalent to smoking 20 a day.)

UNEP figures, too, suggest that deaths due to air pollution rose 12% in India between 2005 and 2010. In the face of this dismal statistic, protecting ourselves against pollution isn’t merely a chore—it’s a survival skill.

INDOOR AIR POLLUTION

The pollutants that contaminate our air outdoors are well known. But outdoor air pollution often seeps into our living spaces, tainting our indoor air as well.

“Indoor pollution is a silent killer,” says Dr Sulaiman Ladhani, consulting chest physician at Breach Candy Hospital, Mumbai. “The lungs and the heart are the most affected with chronic exposure. Recurrent cold, cough, increasing headaches, difficulty breathing, worsening of asthma symptoms, COPD, even cancer [can be caused] by pollution.”

Exhaust fumes from passing vehicles, dust from construction activities, the burning of agricultural waste, smoking—all of this can spoil the quality of air within your home. Constant cooking and the strong chemicals in home cleaning products can contribute to indoor air pollution, too.

Solution: Ventilate

The true solution lies in improving ventilation, says Dr. Ladhani, that is, letting polluted air escape the indoor environment. However, with worse air outside, throwing open a window won’t really provide relief. Installing more exhaust fans in your home – especially in the kitchen and bathrooms – can help keep your home free of smoke and fumes from chemical cleaners. Note that exhaust fans should expel indoor air outside in order to pull indoor air pollution out of your home; fans that simply re-circulate the indoor air don’t solve the problem.

Restricting the use of household cleaning products and switching to natural alternatives, such as lemon and white vinegar, can help to keep the air at home safer, too.

Solution: Purify

Dr Ladhani suggests keeping purifying air conditioners or air purifiers in your home.

“Air conditioners serve the purpose better,” he says. “Use the ones with HEPA (High Efficiency Particle Arrestance) particle filters. These trap and filter out small particles up to 2.5 microns and help in air circulation.”

Air purifiers, now available as compact, tabletop models, also come equipped with HEPA filters. The most effective purifiers filter as much as 99.7 percent of particles that flood the air and can catch particles as small as 0.3 micrometres (for comparison, a strand of human hair is 70 micrometres). This will help reduce your exposure to asthma-causing allergens.

Solution: Go Green

In the 1980’s, NASA scientists studied the efficiency of indoor plants and their role in filtering air pollutants. They found that some plants worked better than others. Rubber plants were found to be good at ridding the air of formaldehyde, a potent carcinogen often found lingering in common household material such as glue, plywood, timber paneling, furniture and cabinetry. Spider plants effectively filtered out carbon monoxide. Money plants and Areca palms, both indigenous to India, were also good natural air filters. Bamboo, dwarf palms, philodendron, chrysanthemums, Chinese evergreens are also top-notch air cleansers. (NASA’s full list of air-filtering plants can be found here.) Keeping one or more of these plants in your home can help you avoid what experts call Sick Building Syndrome—when exposure to these indoor chemicals threaten your health.

OUTDOOR AIR POLLUTION

Smog frequently smothers some of the world’s busiest cities, enveloping entire streets in a veil-like mist. But what exactly is it? Smog is a nasty chemical cocktail: a combination of smoke, water vapor, vehicle exhaust, and chemical byproducts from the burning of coal, oil and gas that react with sunlight, heat and moisture in the swirling atmosphere. These chemicals can be dangerous. Smog contains carbon monoxide, a toxic gas found in vehicle exhaust and smoke. Breathing high levels of this gas, as in heavy smog, can lead to carbon monoxide poisoning, symptoms of which are headaches, dizziness, nausea, and problems with vision and coordination. If you experience any of these symptoms, get to a place with fresher air immediately and then see a doctor, informing him or her that carbon monoxide poisoning is likely.

Smog also contains nitrogen oxides (triggering respiratory ailments, irritation of the eyes, nose and throat), traces of lead (which can damage the brain and nervous system, especially in children), and hydrocarbons from petroleum fumes (which can also cause respiratory difficulties).

Solution: Avoid

The only practical solution to smog is to be aware of the dangers and to avoid or limit exposure. Pay attention to daily radio reports on toxic smog in your city and avoid travelling during peak hours in bad traffic.

“If you must commute, then a (surgical) mask may help afford some degree of protection,” says Dr Ladhani.

Solution: Reduce

Reducing your own carbon footprint will help, too. Use public transport, carpool whenever you can, and, more importantly, check your own vehicle for harmful emissions. All vehicles in India should have a valid PUC (Pollution Under Control) certificate, though this regulation is seldom enforced. But a valid PUC does more than just keep you on the right side of the law; it can help you build a cleaner, better and safer city.