Impact of air pollution on severe acute exacerbation of COPD

Dear editor

We would like to comment on the article “Harmful impact of air pollution on severe acute exacerbation of chronic obstructive pulmonary disease: particulate matter is hazardous” by Choi et al which was published recently.¹ Keeping in view the current state of affairs of our planet, and knowing that industrialization is growing fast, this article is very important in highlighting some critical issues. This is what makes this article interesting and important at the same time.

COPD is a progressive lung disease characterized by persistent symptoms of the respiratory system and decreased airflow. The most common cause is tobacco smoking, while other contributing factors include genetics and air contamination. Long-term exposure to these irritants causes an inflammatory response in the lungs, resulting in narrowing of the small airways and breakdown of lung tissue.²

The solid and liquid particles suspended in air are called particulate matter (PM). Most of them are hazardous for human health. The exact mechanism by which these particles cause adverse effects is unknown, although various epidemiological studies have consistently demonstrated their toxicity.³

In this study, performed as a retrospective analysis, Choi et al have tried to find out the relation between various air pollutants and the incidence of severe acute exacerbations of COPD. This study, which examined various air pollutants causing hospitalization due to exacerbation of COPD during a period extending more than 2 years, concluded that air pollution increases the incidence of such events. PM was found to be the major contributor of air pollution in the studied area. There have been no previous similar studies in the particular region, as claimed by the authors.

Similar epidemiological studies have been conducted in other parts of the world, mostly on the general healthy population. Most of these studies support the association between PM and worsening of respiratory conditions. A review article by Anderson et al reached the conclusion that PM has a small but consistent and significant effect on human health.⁴ However, they agree that overall the small individual effects result in a large global public health burden. We would like to add here that an interesting study by Sacks et al tried to identify the groups susceptible to PM-related health effects; the study focused on age group, low-socioeconomic status, previous cardiovascular or respiratory diseases and genetics.⁵

In our opinion, similar studies must be conducted in other parts of the world, preferably multicenter studies, as results can be affected by factors like particular atmosphere, and racial and cultural differences of different regions of the world. Further studies are needed to make a comparison of PM-related health issues in developing and developed countries. Future studies must be carried out for COPD exacerbations that do not require hospitalizations.