Exposure to particulate matter on the London Underground in healthy subjects and patients with chronic respiratory disease

暴露于环境空气污染——尤其是被称为颗粒物（PM）的微小颗粒——会增加健康状况不佳，在某些情况下还会导致过早死亡。没有直接证据表明乘坐伦敦地铁时接触隧道粉尘会对健康产生影响。然而，这一结论建立在有限的证据基础之上。鉴于长期和短期接触环境空气污染物都被认为对健康有害，我们似乎有理由认为，接触隧道粉尘也是如此，因为隧道中的颗粒物浓度远远高于地面上的颗粒物浓度。然而，考虑到地铁颗粒的物理化学性质与环境空气中的颗粒不同，这意味着目前还不可能说明任何健康风险的性质和程度。在这项研究中，我们将采用一种久经考验的方法来解决伦敦地铁中空气可能对健康的影响。使用与“牛津街”研究相同的协议，我们将调查使用伦敦地铁网络对健康志愿者和患有心肺疾病的受试者的健康影响。这项工作的结果将提供保证，伦敦的地下空气可以安全呼吸，并表明不需要采取进一步的行动来清理地铁网络，或者，如果发现健康影响，那么这将支持进一步清理地下环境的行动。在这种情况下，改善地下环境将有利于所有地下通勤者的健康。

Exposure to ambient air pollution - notably tiny particles called particulate matter (PM) - increases ill health and in some instances early death. There is no direct evidence of impacts on health from exposure to tunnel dust while travelling on the London Underground. However, this conclusion rests on a somewhat limited evidence base. Given that both long- and short-term exposure to ambient air pollutants is understood to be detrimental to health, it seems reasonable to assume that the same would be true of exposure to tunnel dust, when PM concentrations are much higher than those above ground. However, given the different physio-chemical properties of subway particles, compared with those found in ambient air, means that it is not currently possible to state the nature and extent of any health risk.In this study we will utilise a tried and tested approach to address the possible health impacts of the air in the London Underground. Using the same protocols as in our 'Oxford Street' studies we will investigate the health impacts of using the London underground network in healthy volunteers and subjects with cardio-respiratory problems.The outcome of this work will either provide assurance that the London underground air is safe to breathe and indicate that no further action is required to clean up the tube network or, alternatively, if health effects are found then this will support action for further cleaning up the underground environment. In these circumstances an improved underground environment will therefore benefit the health of all underground commuters.