The correct option is: "when constantly inhaled by citizens, this pollution can cause breathing problems and death"
Smoke, also known as "neblumo" or "pollutant mist", is a form of pollution caused by the combination of air with pollutants during a long period of high pressure (anticyclone), which causes air stagnation and, therefore, the permanence of them in the troposphere and sometimes, in the stratosphere, due to their greater density. There are two types of smog: industrial and photochemical.
Smog has some serious consequences that should not be taken lightly: it can cause respiratory problems, especially in people who have asthma; it can damage the lung membranes, causing pain, discomfort, cough and throat irritation; It also produces dry eyes. Smog can cause lung cancer to the same extent or even more than smoking can. Smog also affects trees and crops.