Exposure to Particles and Nitrogen Dioxide Among Workers in the Stockholm Underground Train System

Area of Science:

• Environmental Health
• Occupational Health
• Air Quality Monitoring

Background:

• Urban air pollution, particularly fine particles, poses health risks.
• Underground train systems can have elevated levels of fine particles.
• Understanding occupational exposure in these environments is crucial.

Purpose of the Study:

• To assess particle exposure levels in different occupational groups within the Stockholm underground train system.
• To identify specific job roles with higher particle exposure.
• To analyze variations in exposure and particle characteristics.

Main Methods:

• Measured fine particulate matter (PM1 and PM2.5) over three work shifts for 44 workers.
• Utilized real-time monitoring instruments (pDR, DataRAM) for exposure fluctuations.
• Conducted qualitative analysis of particle content (inductively coupled plasma mass spectrometry) and measured nitrogen dioxide.

Main Results:

• Overall geometric mean for PM2.5 was 37 μg/m³.
• Cleaners/platform workers exhibited the highest exposure (PM2.5 GM: 76.5 μg/m³).
• Ticket sellers had the lowest exposure (PM2.5 GM: 9.3 μg/m³).
• Underground PM levels were five times higher than street level; particles contained high iron.
• Train drivers' nitrogen dioxide exposure was 64.1 μg/m³.

Conclusions:

• Cleaners and platform workers are significantly more exposed to particles than train drivers or ticket sellers.
• PM2.5 concentrations in Stockholm's underground are comparable to New York's but lower than in older systems globally.