| Summary: | Enclosed railway stations hosting diesel trains are at risk of reduced air quality as a result of exhaust emissions that may endanger passengers and workers. Air quality measurements were conducted inside London Paddington Station, a semi-enclosed railway station where 70% of trains are powered by diesel engines. Particulate matter (PM _2.5 ) mass was measured at five station locations. PM size, PM number, oxides of nitrogen (NO _x ), and sulphur dioxide (SO _2 ) were measured at two station locations. Paddington Station’s hourly mean PM _2.5 mass concentrations averaged 16 μ g m ^−3 [min 2, max 68]. Paddington Station’s hourly mean NO _2 concentrations averaged 73 ppb [49, 120] and SO _2 concentrations averaged 25 ppb [15, 37]. While UK train stations are not required to comply with air quality standards, there were five instances where the hourly mean NO _2 concentrations exceeded the EU hourly mean limits (106 ppb) for outdoor air quality. PM _2.5 , SO _2 , and NO _2 concentrations were compared against Marylebone, a busy London roadside 1.2 km from the station. The comparisons indicated that train station air quality was more polluted than the nearby roadside. PM _2.5 for at least one measurement location within Paddington Station was shown to be statistically higher ( P -value <0.05) than Marylebone on 3 out of 4 days. Measured NO _2 within Paddington Station was statistically higher than Marylebone on 3 out of 5 days, while measured SO _2 within Paddington Station was statistically higher than Marylebone on all 3 days.
|
|---|