Due to the air pollution that has been found in underground railway areas and the amount of time that workers spend there during their work hours, questions have been raised regarding the long-term health risks.
The French Agency for Food, Environmental and Occupational Health & Safety ANSES found that mass concentrations of fine particles measured in underground railway areas are much higher than those measured in outdoor air and in air inside housing. Air particles in these areas have physico-chemical properties that are different from outdoor air particles. The main source of these particles with a high concentration of metallic components, mainly iron, and of carbon, is the wearing down of equipment through wheel-brake friction in passenger trains, followed by wheel-rail contact and the contact between rolling stock and the power supply system. By analogy with the well-documented health risks for ambient outdoor air, their harmful effects are expected to impact both cardiovascular and respiratory health. Those concerned include workers in railway transportation operations, transportation and service organisation, shops, police, security, prevention and social work. The health risks are likely to be higher for workers in charge of the maintenance of infrastructures, due to emissions from Diesel engines and from maintenance work.
The Agency recommends continuing to implement measures for the prevention and reduction of exposure to pollutants in the air. In addition, research work should be conducted on the specific long-term toxicity of these particles.