Just when most of us city folks had come to terms with smog and air pollution doing unspeakable things to our lungs, a massive study conclusively shows that the damage begins even before we are born.
Women who live in polluted areas have smaller, lower weight babies than they would have had if they had fed on clean air.
The higher the pollution and the longer the mother’s exposure to air toxins, the lower was the weight of their baby, showed the study of more than 3 million births across nine countries, excluding India.
Apart from delayed development milestones — growth, speech, movement, learning etc — low birth weight babies are more prone to infections and death in the first five years of life.
The majority, of course, survive but have a higher risk of developing conditions such as diabetes and heart disease as adults.
Though the study, published in the Journal of Environmental Health Perspectives, focused on airborne particulate matter from traffic fumes, several studies have shown that indoor pollution from wood fires used for cooking in rural India is equally responsible for underweight — birthweight less than 2.5 kg — babies that account for one in three births in India.
This does not mean that pregnant women and those planning to have a baby should move to a shack by the sea and live on seafood and fresh air.
What they need to do is minimise exposure to avoidable pollutants, cigarette smoke and vehicular fumes being some more easily avoidable ones.
How air pollutions mucks up your health, both in the womb and in the real world, depends on the nature and concentration of the damaging chemicals and duration of exposure.
Air toxins cause stinging and watering eyes, nose irritation , scratchy throat, headaches, nausea and tiredness, signs most commuters are familiar with.
Such acute effects, however, are usually immediate and go away when exposure to the pollutant ends.
In susceptible people, respiratory infections such as bronchitis and pneumonia and aggravation of asthma and emphysema may also occur.
Children are at greater risk because their airways are small and they are generally more active outdoors, as are people over 65 years, who have existing diseases generally weaken immunity.
Over time, it causes decreased lung capacity, chronic respiratory disease, lung cancer, heart disease, and even damage the brain, nerves, liver, or kidneys.
How each pollutants affects the lungs is different, but together they make a toxic cocktail. Gases such as sulphur dioxide (SO2, from coal fires, vehicles, power plants, petroleum refineries) cause lung irritation, wheezing, chest tightness and lung damage, while nitrogen dioxide (NO2, from vehicles, electric utilities, and fossil fires) causes infections, lung irritation and symptoms of cough, chest pain, and difficulty breathing.
Carbon monoxide (CO, from vehicles and fossil fires) causes headaches, lowered alertness, impaired foetal development and in concentrated doses, death.
Worldwide, 4 billion people, mostly women, cook on wood, coal and dung fires, breathing in 200 chemicals and 14 different carcinogens.
Solid particles (suspended particulate matter from vehicles, power plants and wood stoves) work by settling inside the lungs and paralysing the cilia, small hair-like outgrowth of cells that expel pollutants through coughing and sneezing.
This results in pollutants settling inside the lungs and causing permanent damage.
Along with heart attacks and cancers, pollution is leading cause of death and contributes to 40% of all deaths, said a study at Cornell University some years ago.
The study, on how worsening environment and growing population affected the spread of diseases and infections like malaria, tuberculosis and salmonella, concluded that pollution causes 62 million deaths each year.
The numbers may be debatable, but the damage to health is not. Sure, we need clean air laws, but till then, we have to start by avoiding polluting and pollutants as much as we can.