Introduction:
Polycyclic aromatic hydrocarbons (PAHs) are a class of complex organic substances, consisting of carbon and hydrogen atoms that contain at least two benzene rings. Six PAHs have been classified as possible carcinogenic compounds to humans: benzo(a)anthracene (BaA), benzo(b)fluoranthrene (BbFlu), benzo(k)fluoranthrene (BkFlu), benzo(a)pyrene (BaPy), dibenzo(a,h)anthracene (DahA) and indeno1,2,3-cd-pyren (IPy). It is known that PAHs compounds, such as benzopyrene, anthracene and acenaphthylene, are capable of producing toxic, mutagenic and carcinogenic effects, being an important risk factor for respiratory diseases, such as lung cancer and COPD.

Material and Methods:
This observational study aimed to evaluate the serum concentration of carcinogenic PAHs (BA, B(b)Flu, B(k)Flu, BaPy, D(a,h)A, IPy) according to smoking status (smoker, non-smoker/ex-smoker) and to smoking consumption (number of packs-years, PY) in 52 patients diagnosed with COPD in different stages of disease severity.

Results:
BaPy was significantly higher in the group of smokers diagnosed with COPD (mean concentration = 1.21 ng/mL) and was higher than in the group of former smokers (mean concentration of 0.56 ng/mL), but also compared to the group of non-smoker patients (mean concentration = 0.87 ng/mL). The regression summary for the dependent variable showed an important correlation between BaPy concentration and PY. The factorial analysis applied to the data set generated 3 factors with a variance of 52% represented by carcinogenic PAHs, such as BaA, DahA, B(b,k)Flu and BaPy.

Conclusions:
The accumulation of pollutants according to smoking status showed higher serum concentrations of carcinogenic PAHs in smokers (ΣPAHs = 6.76 ng/mL) compared to non-smokers and ex-smokers COPD patients. The most abundant carcinogenic PAHs were BaPy in smokers, DahA for non-smokers, and B(b)Flu for former smokers.