It is known that air pollution affects human health and commuting environments are significant contributors to the total daily personal exposure to air pollution. With this study we aim at assessing and comparing personal exposure to traffic-related air pollution and related estimated inhaled dose of different typical commuter profiles in real-world scenarios focusing on multimodal commuting and different transport microenvironments. A car driver and two multimodal commuters (cyclist/public transport and pedestrian/public transport commuters), which reached the same destination in the city center, leaving from the same starting point in the metropolitan area of the city, were investigated in the metropolitan area of Milan, Italy. Real-time monitors for the measurement of size-fractionated particulate matter (PM - Aerocet 831-Met One Instrument Inc., Grant Pass, Oregon, USA), equivalent Black Carbon (eBC - Aethlabs, San Francisco, CA, USA), and NO₂ (CairClip NO₂, Cairpol; La Roche Blanche, France) and time-integrated samplers for the measurement of NO₂ and benzene were used. Inhaled dose was estimated as well by applying estimated pulmonary ventilation rates to 1-min exposure measures. The Bootstrapping method was used to resample data and perform more robust comparisons among commuters and microenvironments (MEs). Results of the study could be summarized as follows: (i) travel times of the cyclist were the shortest; (ii) the highest concentrations and estimated inhaled doses were found during morning rush hour; (iii) the cyclist and the car commuter were exposed to the highest overall median values of fractionated PM and benzene, respectively; (iv) cycling MEs presented the highest median concentrations of PM, while the overall median concentration of eBC was higher commuting by car than walking and cycling; (v) the cyclist was the commuter with the highest overall median estimated inhaled dose for fractionated PM, while benzene was the highest for the car driver, and NO₂ for the pedestrian; (vi) exposure differences both among microenvironments and commuters diverged comparing morning and evening commuting. Our results suggest that a multi-pollutant approach is necessary to better represent the complexity of personal exposure to traffic-related air pollution in multimodal mobility studies. Moreover, shifting from car driving to multimodal mobility is already a valuable choice for the metropolitan area of Milan considering both exposure and commuting time. However, to further reduce personal exposure and especially estimated inhaled dose of multimodal and active commuters, exposure mitigation interventions in selected MEs, traffic calming, and innovative mobility policies are still needed.

众所周知，空气污染会影响人类健康，而通勤环境是造成个人日常空气污染总暴露量的重要因素。通过这项研究，我们旨在评估和比较个人暴露于与交通相关的空气污染和相关的不同典型通勤者吸入剂量的相关估计，在侧重于多模式通勤和不同交通微环境的现实世界场景中。在都市区调查了一名汽车司机和两名多式联运通勤者（骑自行车/公共交通和步行/公共交通通勤者），他们到达市中心的同一目的地，从城市都市区的同一起点出发意大利米兰。用于测量粒度分级颗粒物的实时监测器（PM - Aerocet 831-Met One Instrument Inc.₂（CairClip NO ₂，Cairpol；La Roche Blanche，法国）和时间积分采样器，用于测量 NO ₂和苯。吸入剂量也通过将估计的肺通气率应用于 1 分钟暴露措施来估计。Bootstrapping 方法用于重新采样数据并在通勤者和微环境 (ME) 之间进行更稳健的比较。研究结果可概括如下： (i) 骑自行车者的行程时间最短；(ii) 在早高峰时段发现最高浓度和估计吸入剂量；(iii) 骑自行车者和汽车通勤者分别接触到最高的分馏 PM 和苯的总体中值；(iv) 骑自行车的 ME 的 PM 中值浓度最高，而 eBC 的总体中值浓度是开车通勤高于步行和骑自行车；₂为行人；(vi) 微环境和通勤者之间的暴露差异与早晚通勤相比有所不同。我们的结果表明，在多模式交通研究中，为了更好地代表个人暴露于交通相关空气污染的复杂性，需要一种多污染物方法。此外，考虑到曝光率和通勤时间，从汽车驾驶转向多式联运已经成为米兰大都市区的宝贵选择。然而，为了进一步减少个人暴露，尤其是多式联运和活跃通勤者的估计吸入剂量，仍然需要在选定的 ME 中进行暴露缓解干预、交通平静和创新的出行政策。