*2.4. Respiratory Disorders*

Asthma and chronic obstructive pulmonary disease (COPD) are major respiratory disorders, accounting for high mortality worldwide [38]. Exposure to cigarette smoke and air pollutants significantly contributes to the overproduction of ROS in both asthma and COPD patients. The ROS primarily affects and damages the alveolar and connective tissues of the pulmonary system [39]. The overproduction of ROS also triggers the inflammatory cells, which, as a result, shows production of ROS in the pulmonary system. The ROS are predominantly observed during pathophysiology analysis for both asthma and COPD [40]. It is still unclear how increased ROS is a causative factor for

these respiratory diseases [41]. Researchers are extensively working in this direction to decipher the role of these ROS in progression of these fatal diseases.

This synergism between ROS and these chronic diseases shows the major challenge associated with oxidative stress induced by ROS, and requires the effective solution to meet the challenges imposed by the overproduction of ROS.
