Researchers figured this out by exposing cells taken from the bottom of hair follicles on the scalp to ‘particulate matter’ – pollutants produced by cars and industry.
The results showed that the presence of a pollutant called PM10 and diesel particulates decreased levels of β-catenin, the protein responsible for hair growth. ( according to the article from metro.co.uk)
They also found that three other proteins that are responsible for hair growth were decreased by exposure tot he same substances.
Lead researcher Hyuk Chul Kwon from the Future Science Research Centre in the Republic of Korea said;
‘Our research explains the mode of action of air pollutants on human follicle cells, showing how the most common air pollutants lead to hair loss.’
The research suggested the risk is ‘dose-dependent manner’, meaning that more pollution will result in greater hair loss.