It’s all in the air

A mix of diesel emissions and nitrogen dioxide makes children susceptible to asthma. Sanchita Sharma tells more.

As I write this, sitting on a hilltop in Ranthambhore, I’m reminded of what I miss the most in Delhi: clean air. The breeze is crisp and fresh, and despite the fine dust in the air — after all, we are in arid Rajasthan — my son’s energy levels are up. He effortlessly races up the hillside chasing a wild deer (but only after confirming he was not in any danger of getting head-butted by his quarry).

The reason for his high energy, of course, is the clean air and the near absence of traffic in the close confines of the hotel. Recently, an international study clearly established what was always suspected: that traffic pollution worsens the respiratory health of children who have asthma. Researchers from Mexico’s Institute Nacional de Sauld Publica reported in Respiratory Research (November 14) that asthmatics living in polluted areas need stronger medication for longer to control their asthma.

While earlier studies had suggested that traffic pollution worsens respiratory health, none had clearly linked ozone, nitrogen dioxide and diesel particles to more coughing, wheezing and medication usage in asthmatic children. Even in
healthy children, higher levels of nitrogen dioxide increased coughing.

There are 20 million severe asthmatics in India on regular medication to control airway inflammation (swelling). About 10-15 per cent five to 11 years olds have asthma, though almost half outgrow it by their teens. Children are more susceptible to allergic respiratory problems because they have small airways and any infection — something as innocuous as a mild viral — may cause inflammation, making it difficult for them to breathe.

Delhiites have it the worst, since one in seven people live with asthma here. Of them, about 20 per cent get an acute asthma attack at least once in the winter. Vehicular emissions combine with cold temperature to form a toxic blanket over the city, becoming a deadly trigger. And the number of new asthmatics is bound to go up. In Delhi alone, about 1,000 new cars are added to the four million that are already registered.

Rising diesel emissions are an emerging problem, as diesel fumes — a mix of carbon monoxide, carbon dioxide, sulfur dioxide, nitrogen oxides and mercury — contain up to 100 times more particles (suspended particulates) than petrol exhaust. What makes matters worse is that diesel can cause asthma attacks long after the initial allergen contact, at times hours after exposure to pollution, reports the Journal of Allergy and Clinical Immunology.

Attacks can be relieved with salbutamol inhalers (short-acting beta 2-agonists) that dilate airways. A combination of the inhaled steroid fluticasone propionate and the long-acting beta 2-agonist salmeterol is quite effective in controlling asthma.