School of Environment, Faculty of Science, University of Auckland, Private Bag 92019, Auckland, New Zealand; Mote Ltd, 40a George Street, Mount Eden, Auckland, New Zealand.
School of Environment, Faculty of Science, University of Auckland, Private Bag 92019, Auckland, New Zealand.
Sci Total Environ. 2023 May 20;874:162540. doi: 10.1016/j.scitotenv.2023.162540. Epub 2023 Mar 3.
Auckland is a city with limited industrial activity, road traffic being the dominant source of air pollution. Thus, the time periods when social contact and movement in Auckland were severely curtailed due to COVID-19 restrictions presented a unique opportunity to observe impacts on pedestrian exposure to air pollution under a range of different traffic flow scenarios, providing insights into the impacts of potential future traffic calming measures. Pedestrian exposure to ultrafine particles (UFPs), was measured using personal monitoring along a customised route through Central Auckland during different COVID-19-affected traffic flow conditions. Results showed that reduced traffic flows led to statistically significant reductions in average exposure to UFP under all traffic reduction scenarios (TRS). However, the size of the reduction was variable in both time and place. Under the most stringent TRS (traffic reduction of 82 %), median ultrafine particle (UFP) concentrations reduced by 73 %. Under the less stringent scenario, the extent of reduction varied in time and space; a traffic reduction of 62 % resulted in a 23 % reduction in median UFP concentrations in 2020 but in 2021 similar traffic reductions led to a decrease in median UFP concentrations of 71 %. Under all scenarios, the magnitude of the impact of traffic reductions on UFP exposure varied along the route, with areas dominated by emissions from construction and ferry/port activities showing little correlation between traffic flow and exposure. Shared traffic spaces, previously pedestrianised, also recorded consistently high concentrations with little variability observed. This study provided a unique opportunity to assess the potential benefits and risks of such zones and to help decision-makers evaluate future traffic management interventions (such as low emissions zones). The results suggest that controlled traffic flow interventions can result in a significant reduction in pedestrian exposure to UFPs, but that the magnitude of reductions is sensitive to local-scale variations in meteorology, urban land use and traffic flow patterns.
奥克兰是一个工业活动有限的城市，道路交通是空气污染的主要来源。因此，由于 COVID-19 限制措施，奥克兰的社会接触和流动受到严重限制的时期提供了一个独特的机会，可以观察在一系列不同的交通流量情况下，行人接触空气污染的影响，为潜在未来交通减缓措施的影响提供了见解。使用个人监测在奥克兰市中心通过一条定制路线测量行人暴露于超细颗粒（UFPs），在不同的 COVID-19 影响的交通流量条件下。结果表明，减少交通流量导致在所有交通减少情况下（TRS），平均暴露于 UFPs 的统计显著减少。然而，减少的幅度在时间和地点上是可变的。在最严格的 TRS（交通减少 82%）下，中值超细颗粒（UFP）浓度减少了 73%。在较不严格的情况下，减少的程度在时间和空间上有所不同；交通减少 62%导致 2020 年中值 UFP 浓度降低 23%，但在 2021 年，类似的交通减少导致中值 UFP 浓度降低 71%。在所有情况下，交通减少对 UFP 暴露的影响程度沿路线变化，受建筑和渡轮/港口活动排放控制的区域与交通流量和暴露之间相关性较小。以前是行人专用的共享交通空间也记录到了一致的高浓度，几乎没有观察到可变性。本研究提供了一个独特的机会，可以评估此类区域的潜在好处和风险，并帮助决策者评估未来的交通管理干预措施（如低排放区）。结果表明，受控交通流量干预措施可显著降低行人接触 UFPs，但减少的幅度对气象、城市土地利用和交通流量模式的局部尺度变化敏感。
