it may escape one's notice, but every time we breathe, we inadvertently inhale an invisible stream of gases, aerosols, particles, microbes, pollen and dust into our lungs. Although many take it for granted, it is an act that is not easy on millions of people all over the world. The encounter with allergens, irritants, cold air or viral infections could trigger a complex series of events leading to the inflammation and constriction of the air passage. The victims of all such conditions are innocent prey to asthma, the invisible strangler. The condition, according to most researchers seems to be caused primarily due to the quality of our environment ( Environmental Health Perspective , Vol 104, No 1).

Emissions of soot and smog-forming volatile organic compounds