The impacts of the ultra low emission zone (ULEZ) and COVID-19 restrictions on air quality in central London – evidence for an increase in small particles (Code)

This research used the ALICE High Performance Computing facility at the University of Leicester. The Detrend.R script utilises the "deweather" R package which is currently in active development (Carslaw D (2025). deweather: Remove the influence of weather on air quality data. R package version 0.7.2.9104, https://openair-project.github.io/deweather/.). The script was written and executed in spring 2024, and has not been amended to reflect the continued development of the package. This script was executed in a Linux environment using R 4.3.1, with a seed of 56117. Analysis was undertaken using predominantly in R 4.5. Modelled wind speed, modelled wind direction, modelled air temperature, NO2, O3, PM10 and PM2.5 data used in this study are publicly available via the UK AIR Data Selector or the “openair” R package. Relative humidity data for St James’s Park, as used in this research, is available via the NOAA Integrated Surface Database (NOAA-ISD) via the “worldmet” R package. MIDAS Open hourly rainfall and solar radiation observations for Kew Gardens, as used in this study, are available via CEDA Archive. Hourly traffic count data for Marylebone Road is available via the responses to two FOI requests made to Transport for London. Particle size and number distribution data used in this study was not rounded to the nearest whole number and is not available publicly, however a rounded version is available via the UK Air Data Selector.本研究使用了莱斯特大学（University of Leicester）的ALICE高性能计算设施。 本研究使用的Detrend.R脚本依赖目前仍处于活跃开发阶段的"deweather" R程序包（Carslaw D (2025). deweather: Remove the influence of weather on air quality data. R package version 0.7.2.9104, https://openair-project.github.io/deweather/.）。该脚本于2024年春季编写并运行，未针对该程序包后续的迭代更新进行适配修改。本脚本在Linux环境下基于R 4.3.1执行，随机种子设置为56117。分析工作主要依托R 4.5完成。 本研究使用的模拟风速、模拟风向、模拟气温、二氧化氮（NO2）、臭氧（O3）、PM10与PM2.5数据可通过UK AIR数据选择器（UK AIR Data Selector）或"openair" R程序包公开获取。本研究中使用的圣詹姆斯公园相对湿度数据可通过NOAA综合地面数据库（NOAA Integrated Surface Database）结合"worldmet" R程序包获取。本研究使用的邱园MIDAS开放逐时降雨与太阳辐射观测数据可通过CEDA档案馆获取。马里波恩路逐时交通流量数据可通过针对伦敦交通局（Transport for London）发起的两项信息自由（FOI）申请的回复获取。本研究使用的颗粒物粒径与数量分布数据未进行整数四舍五入处理，暂未公开，但经过整数四舍五入的版本可通过UK Air数据选择器获取。