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Poison in the air: Many ways in which pollution hurts your health

With the New Year, the Delhi government implemented the odd-even plan or road space rationing in an effort to check the Capital’s alarming level of air pollution. Here’s a look at the hazards of air pollution.

india Updated: Jan 01, 2016 11:42 IST
Sanchita Sharma
Sanchita Sharma
Hindustan Times
A civil defence volunteer holds a placard during a trial run of the odd-even car scheme at ITO in New Delhi.
A civil defence volunteer holds a placard during a trial run of the odd-even car scheme at ITO in New Delhi.(PTI)

With the New Year, the Delhi government implemented the odd-even plan or road space rationing in an effort to check the Capital’s alarming level of air pollution.

Air pollution is not only about toxic air as it does more than just trigger asthma and wheezing. Stepping out in polluted air can make your eyes sting, your nose run, your throat dry and itchy, and your head ache. It often causes nausea, dizziness, headache and chronic allergy. Over time, it kills by triggering heart attacks, stroke and cancers.

Outdoor air pollution caused 6.2 lakh premature deaths in India in 2010, a six-fold jump from the 1 lakh deaths in 2000. This makes polluted outdoor air the fifth biggest killer in India after high blood pressure, indoor air pollution (mainly from smoking chullahs that use biomass fuels such as wood, coal, straw, manure, etc), tobacco use, and poor nutrition, says the Global Burden of Disease 2013 (, which tracks deaths and illnesses from all causes every 10 years.

It is world’s biggest environmental health risk, exacerbating respiratory and heart diseases and triggering deaths from stroke (25.48%), chronic obstructive pulmonary disease (17.32%), heart disease (48.6%), lung infections (6.4%), and trachea, bronchus and lung cancer (2.02%).

Read: Live: New year off to odd start as Delhi tries out traffic rationing

Toxic air

One in three people in India live in critically polluted areas that have noxious levels of nitrogen dioxide (NO2), sulphur dioxide (SO2) and lung-clogging suspended particulate matter smaller than 10 micron (SPM10) in size. Of the 180 cities monitored by India’s Central Pollution Control Board in 2012, only two -- Malapuram and Pathanamthitta in Kerala -- meet the criteria of low air pollution (50% below the standard).

Just being stuck in heavy traffic can trigger heart attacks. People who have already had a heart attack were more than three times as likely to have been in traffic within an hour of getting a heart attack, found a study of 1,454 in Germany, with the risk being highest for women, people over 65 and those with existing heart disease.

Exposure to traffic noise makes children hyperactive and sleepless, report researchers in the journal Environmental Research. Sleeping in rooms exposed to the sound of nighttime traffic raises children’s blood pressure, reports a study in the journal Noise Health.

Here’s how the top three components of polluted air hurt your mind and body:


Smog is produced when airborne dust, carbon particles, noxious gases and ozone react chemically in the presence of sunlight to create a toxic mist that aggravates bronchitis, asthma, and other lung problems and reduces lung function even in healthy people. There are no safe levels of smog.

Inhaling smog tightens the arteries, reducing the blood flow, and triggering heart attacks and stroke, report Harvard research in the journal Circulation. At most risk are people who have had a heart attack or angioplasty or those who have angina, heart failure, heart rhythm problems, and/or diabetes.


Ground-level ozone, which is the main constituent of smog that hangs low over Delhi throughout the year, irritates the eyes, nose, and throat. When it is inhaled, it dehydrates and inflames the protective membranes of the nose and throat, raising risk of throat and lung infections.

Apart from aggravating asthma, exposure to ozone for just six to seven hours, even at relatively low concentrations, triggers asthma attacks, lowers lung function and triggers wheezing in healthy people. People over 65, children under 12 and people with asthma and lung disorders need to limit exposure as much as possible.

Suspended particles

Suspended particulates (SPM10 and SPM2.5) from diesel and petrol fumes, power plants, industry, agricultural fires and construction dust remain hanging and air and cause irreversible damage lung and respiratory tissue damage. Combined with ground-level ozone, the main constituent of smog, SPM causes wheezing, coughing and breathing difficulties, especially during exercise.

SPM give lower visibility and contribute to the brownish-yellow colour characteristic of smog.

SPM2.5 and below are more deadly. Unlike larger particles that get filtered by the mouth and lungs, fine airborne particles are inhaled deeper and get lodged in the lower regions of the respiratory tract to lower the lungs’ working capacity and aggravates respiratory problems.

Over time, exposure damages lung tissue, causes cancer and premature death.

Read: Delhi’s odd-even plan: Genius or a recipe for nightmare?

Nitrogen oxides

Nitrogen dioxide (NO2) and other oxides of nitrogen (NOX), formed from vehicular emissions and electricity and industrial plants, irritate the airways and cause frequent nose, throat and lung infections such as bronchitis and pneumonia. People who live near busy highways are at most risk.

NO2 concentrations are 30 to 100% higher within about 50 metres from busy roads as compared to areas away from roadways. NOX reacts with volatile organic compounds in the presence of heat and sunlight to form deadly ground-level ozone.

Sulphur dioxide

Sulphur dioxide (SO2) is released from burning fuels that contain sulphur (coal, oil, diesel etc) and from coal- and oil-fired power plants, pulp and paper mills, steel mills and smelters.

Short-term exposure affects breathing and causes wheezing, chest tightness, shortness of breath, sore throat and nose irritation. Long-term exposure aggravates breathing and heart problems, with people with asthma, chronic bronchitis, emphysema, children and people over 70 being at most risk.

Activity barometer

Exercise caution on highly polluted days

· Limit time outdoors and avoid areas where air quality is poor, such as near busy roads and at times of day (early mornings and peak traffic hours) when air pollution levels are high.

· Moving activity indoors reduces ozone exposures, especially if your windows are shut and you have the air conditioner on. Other air pollutants may be present, though at lower levels.

· Change your activity levels. If you walk instead of run, for example, the amount of polluted air you inhale is reduced.

· Use only N95 or P100 face-masks (respirators) that effectively remove very small airborne particles.

· While free-standing air-filter units lower airborne particles (not gas), they are not proven to protect against the adverse effects of indoor cigarette smoke (which emits both particles and gases) on heart or lung disease.

· People with asthma, allergies, pregnant women, smokers and people who have diagnosed heart disease should avoid even routine activity in heavily polluted air.

Read: Delhi’s air quality ‘worse than 2014 winter’

Signs of bad air

Spending just a few minutes in polluted air can cause:

Eye irritation; cough; sore throat (pharyngitis); shortness of breath (dyspnoea); headache; nausea; vomiting; conjunctivitis; abdominal pain (stomach ache); respiratory problems; rhinitis (runny nose); bronchitis; burning mouth and throat, nosebleed (epistaxis), depression

Long-term exposure to polluted air causes irreversible health damage, which may include:

Damage to lung tissue, decreased lung function

Aggravated asthma, bronchitis, emphysema, and/or lung cancer

High blood pressure, heart disease, stroke

Insulin resistance and diabetes

Shortened lifespan

People at most risk

Though the actual risk depends on your current health status, the pollutant type and concentration, and the length of exposure to the polluted air, people at most overall risk are:

· Those with heart disease , including coronary artery disease or congestive heart failure

· Those lung disease – such as asthma, emphysema or chronic obstructive pulmonary disease (COPD)

· Pregnant women

· Outdoor workers

· Children under age 14, who have lungs that are still developing

· Athletes or people who are very active outdoors

(Source: All India Institute of Medical Sciences; World Health Organization)