The exaggerated response of the immune system to certain antigens present in the environment is called allergy. The substances to which such an immune response is produced are called allergens. Common examples of allergens are mites in dust, pollens, animal dander, etc. Symptoms of allergic reactions include sneezing, watery eyes, running nose and difficulty in breathing. Allergy is due to the release of chemicals like histamine and serotonin . Somehow, modern-day life style has resulted in lowering of immunity and more sensitivity to allergens. This could be because of the protected environment provided early in life.

Who among the following is more susceptible to allergy ?

A person living in a polluted city.

The increased rates of allergy and asthma in city environments and in those living close to highways has drawn attention to the role of outdoor pollution. Common air pollutants, such as ozone, sulfur dioxide, and nitrogen dioxide probably act more as irritants than as promoters of sensitization. These pollutants have been shown to be hazardous to adults and children with asthma. Allergies are more common in polluted cities.