Analyzing London's Smoke-Free Underground Trains
A decision by the London Underground to end smoking in 1984 reflected the accelerating trend toward smoke-free environments that was beginning in the mid-to-late 1980s. One of the B&W documents is a report titled "An Investigation of the Atmosphere in London Underground Trains" {1181.04}, which was part of the papers for the 1984 research conference. Neither the author nor the audience is identified in the report, but it appears to have been part of an effort to gather data to demonstrate that ETS is not an important source of indoor air pollution. The report notes that smoking was ended on all Underground trains for a one-year trial period beginning July 9, 1984, and that a study was conducted to measure the air quality before and after ending smoking. Be-
fore smoking was ended, levels of nicotine and particulates were higher in the smoking cars than in the nonsmoking cars. However, all levels were below the industrial safety limits.
Before the total ban on smoking was introduced, smoking compartments contained on average five times the concentration of nicotine and four times the concentration of airborne particles as compared to non-smoking carriages. However, the concentration of nicotine (c. 30 µg/m3 ) and particulates (c. 0.7 mg/m3 ) found in the smoking areas are similar to those that are likely to be encountered in typical offices and public houses, and are far below recommended industrial limits for safe exposure (500 µg/m3 for nicotine). {1181.04}
One month after smoking had been ended, nicotine levels were lower than they had been in both smoking and nonsmoking cars. These results suggest that some smoke had been leaking into the nonsmoking cars. Moreover, there had been significantly elevated levels of air pollution when smoking was present, and these levels were reduced by ending smoking. The report, however, does not comment on either of these findings. Instead, it reiterates that levels of nicotine and particulates measured did not exceed recommended exposure levels.