Residential proximity to main road and the risk of COPD

Sir, We read the article by Surendran et al.,[1] which studied the risk factors associated with COPD in an urban area of Trivandrum, Kerala, using spatial analysis, with great interest. Their study showed a significant association between proximity to main roads and prevalence of COPD, suggesting that proximity to road traffic may be a risk factor for developing COPD. Similar observations have been reported in the past from France,[2] Japan,[3] China,[4] and Germany.[5] Several studies have shown that, residing close (<100 m) to a major road has a detrimental effect on lung function and can increase the risk of allergic diseases and asthma.[5]