Air Pollution and DNA Damage
By Dr Arvind Kumar
A link between exposure to certain air pollutants and an increase in DNA damage for people exposed to high levels of the pollution has been confirrmed by a recent study in the Czech Republic. The study reveals that breathing small quantities of a polycyclic aromatic hydrocarbon (PAH), called benzo[a]pyrene (B[a]P), caused an increase in the number of certain ‘biomarkers’ in DNA associated with a higher risk of diseases, including cancer. Air pollution is a major problem around the world, particularly in urban areas. In attempt to control regional air pollution levels, the EU has introduced legal limits for exposure to a variety of different airborne pollutants. For B[a]P , the EU air quality standard is 1 nanogram per metre3 (ng/m3) as an annual average that has to be attained where possible throughout the EU.
To measure the risk of DNA damage and risk to health caused by exposure to chemicals, such as PAHs, researchers sometimes use ‘biomarkers’ — these are biological features that can provide an indicative picture of risk and disease. Past studies have suggested that ‘DNA adducts’ can be used as biomarkers to measure exposure to PAHs. These are, in effect, small molecules, such as PAHs, bound to the DNA. Similarly, ‘chromosomal aberrations’ – structural changes to a stretch of DNA – can be used as biomarkers to demonstrate the effect of some pollutants on DNA. The results revealed, for the first time, a significant relationship between exposure to PAHs, the number of DNA adducts and the number of chromosomal aberrations detected using FISH. In particular, PAH levels and the occurrence of the two biomarkers were higher in winter than in summer.
