Background:
Smoking is recognized as the main risk factor for the development of COPD. However, studies have shown that half of smokers who are highly addicted to nicotine do not develop COPD, and that non-smokers may also develop COPD throughout their lives. Polycyclic aromatic hydrocarbons (PAHs) are a class of complex organic substances, consisting of carbon and hydrogen atoms, that contain at least two benzene rings that can be used as a biomarker of air pollution exposure.

Objective:
Assessment of air pollution exposure in relation with smoking status in COPD patients.

Methods:
In this observational study, a number of 15 PAHs were investigated for 51 patients diagnosed with COPD, hospitalized at the Clinical Hospital of Pulmonary Diseases, Iasi, Romania. The study mainly focuses on the quantification of PAHs in the blood of patients diagnosed with COPD and the assessment of the admission of these contaminants according to smoking status and exposure to air pollution.

Results:
Evaluation of PAHs in the investigated samples revealed high concentrations for patients with COPD stage II and III compared to the values of the concentrations in patients with stage IV. The results show that the concentrations of non-carcinogenic PAHs were much higher than carcinogenic PAHs and the order of admission was non-carcinogenic ΣPAHs non-smoker > noncarcinogenic ΣPAHs former smoker > non-carcinogenic ΣPAHs smokers. The most abundant carcinogenic PAHs were BaPy in smokers, DahA for non-smokers and B(b)Flu for former smokers. The ranking of admission of carcinogenic PAHs according to smoking status was carcinogenic ΣPAHs smokers > carcinogenic ΣPAHs non-smokers > carcinogenic ΣPAHs former smokers.

Conclusions:
Beside smoking, air pollution is a risk factor for COPD and the present study shows that the levels of PAH were high among the investigated patients. More studies should be conducted in this field with the purpose to find the way in which pollutants contribute to the development of this disease.