Lung can:cer has long been associated with smoking; however, in recent decades, a significant rise in cases among people who have never smoked has challenged this assumption. This phenomenon has driven researchers to explore other contributing factors such as environmental pollution, chemical exposure, and genetic predispositions that may influence the development of the disease.
In 2017 alone, approximately 1.57 million new cases were reported in men and more than 900,000 in women, underscoring the global magnitude of this public health concern. These statistics highlight the importance of understanding the multifactorial causes behind lung cancer in nonsmokers, including environmental, genetic, and lifestyle factors.
Definition and Scope of the Problem
Lung cancer is characterized by the uncontrolled growth of abnormal cells in lung tissue, which compromises normal respiratory function. Although tobacco use remains the dominant risk factor, between 10% and 20% of diagnosed cases occur in individuals who have never smoked. Among these, adenocarcinoma is the most common subtype—accounting for 59.7% of cases in women and 45.6% in men—according to global studies.
Air Pollution and Environmental Factors
Air pollution is one of the primary environmental contributors to lung cancer in nonsmokers. Fine particulate matter (PM2.5 and PM10), which often exceeds safe levels in industrial and urban areas, can trigger chronic inflammation and genetic mutations in lung tissue. Data from global analyses reveal that East Asia and North Africa record the highest incidence rates for certain subtypes of lung cancer related to pollution exposure.
Another key factor is radon, a naturally occurring radioactive gas that seeps from the ground into homes and buildings. In poorly ventilated spaces, radon accumulation can expose residents—smokers and nonsmokers alike—to harmful radiation, increasing their cancer risk. Regular radon testing and proper ventilation are therefore strongly recommended, particularly in regions known for elevated radon levels.
