Indoor air pollution and asthma in children at Delhi, India

Several studies in developed countries have shown association between indoor air pollution and asthma in children. The present research was undertaken to study this association at Delhi, India.

This study took place at Delhi, capital of India. Eight locations based on the source of pollution such as industrial, residential and villages were included. Recording of the demographic profile and clinical examination of each child was conducted at their residence. Indoor SO₂, NO₂ and SPM (suspended particulate matter) levels were measured by using Handy Air Sampler (Low Volume Sampler).

A total of 3104 children were examined of which 60.3% were male and 39.7% were female. 32.4% children were exposed to environmental tobacco smoke. 31.5 % children's families were using biomass fuels for cooking. History of respiratory symptoms included cough (43.9%), phlegm production (21.9%), shortness of breath (19.3%) and wheezing (14.0%). 7.9% children were diagnosed as having asthma, which was highest in industrial areas (11.8%), followed by residential (7.5%) and village areas (3.9%). The mean indoor SO₂, NO₂ and SPM levels were 4.28 ± 4.61 mg/m³, 26.70 ± 17.72 mg/m³ and 722.0 ± 457.6 mg/m³ respectively. Indoor SPM was the highest in industrial area followed by residential area and urban village area. Indoor SPM level was significantly (p < 0.001) higher in the asthmatic children's houses.

This study suggests that industry plays an important role in increasing the concentration of indoor suspended particulate matter and occurrence of asthma in children in developing countries like India.