Children are not simply small versions of adults but are “energy packets”, due to intense activity and their dynamic state of growth with cells multiplying and organ systems developing, i.e. the number of alveoli increases as they grow. Due to this nature they are considered as the most susceptible and sensitive group of the whole population. In India, children spend a crucial time of the day (about five to six hours) in school buildings, which are usually naturally ventilated. The work highlights children’s exposure due to high levels of PM concentration and metal contamination in school buildings of developing countries like India, where conditions are not so good, leading to increased health symptoms. Thus their health is at greater risk than children without such conditions.