CoMobility project data: Warsaw road traffic, road traffic emissions, and air concentrations for greater Warsaw area

Introduction

Data here are for the Greater Warsaw area, Poland originating in the CoMobility project. It contains data relevant to traffic activity, emissions, air quality and related health studies in the area. Files contain road properties along with traffic volume and rushhour delays as well as emissions of NOx, NO2 and PM from road traffic on individual road segment level. Also 500m gridded surface air concentrations are included for PM2.5 and PM10, and for NOx, NO2.

Data production

Roads are from the macroscopic traffic model MTAW (Warsaw Municipality, 2016) (Model Transportowy Aglomeracji Warszawskiej in Polish). It was developed based on the 2015 comprehensive travel survey in Warsaw and it is the main strategic transport model for the Greater Warsaw area, revised most recently in 2019. 

The NERVE model (Grythe et al, 2022), developed by NILU, provides detailed estimates of greenhouse gas and air pollutant emissions specifically from road traffic. Using a bottom-up approach, it combines data from regional traffic model (RTM), vehicle fleet composition, and emission factors from the Handbook Emission Factors for Road Transport (HBEFA). NERVE can be set up to calculate emissions at various levels, including road link, municipality, or national levels. It is a tool researchers and policymakers use this model for environmental assessments, policy decisions, and constructing different emission scenarios. Its high level of detail makes it valuable not only for practical emissions estimation but also as a research tool. Emissions for other sources came from the Central Emission Database by the Environmental Protection - National Research Institute (IEP-NRI) in Poland (Gawuc et al., 2021). The background concentrations were taken from the Copernicus Atmospheric Monitoring Services (CAMS) ensemble forecast for 2019 (Marécal et al., 2015)

The EPISODE model (Hamer et al. 2020), developed by NILU, is an Eulerian urban dispersion model designed to address the need for an accurate urban air quality model in support of policy, planning, and air quality management. EPISODE operates as a 3D grid model coupled with numerical weather prediction (NWP) data. It simulates dispersion from point and line sources to receptor points, with a focus on the photochemical production of ozone in urban areas. The model’s CityChem extension enhances its capabilities for complex pollution sources, incorporating numerical chemistry solvers, sub-grid photochemistry, and a simplified street canyon model. EPISODE serves as a valuable tool for understanding and managing air quality in urban environments.

Data files

The data on road traffic contains 60 084 road links that cover the Greater Warsaw area. The file input is a traffic file from the MTAW model and is processed and formatted with NREVE. The format is an ESRI shapefile with the following road parameters:

“DISTANCE” -length of road segment in kilometers.

“CAPACITY” -Hourly capacity of the road.

“SLOPE” -Vertical gradientor slope of the road (in %)

“SPEEDLIM” -Signed speed on the road (kilometers per hour)

In addition there are traffic volume parameters;

“ADT_LIGHT” – Annual Daily Traffic, light vehicles (personal cars + light duty vans) average derived from morning and evening peak hours 2019.

“ADT_HEAVY” – Annual Daily Traffic, heavy duty vehicles average derived from morning and evening peak hours 2019.

“ADT_BUSES” – Annual Daily Traffic, public transport buses average 2019.

“MRN_delay” – delay during morning rush hour peak (%)

“EVE_delay” – delay during evening rush hour peak (%)

The files also contain the annual emissions:

“EM_NOx” – 2019 annual emissions of NOx (gram).

“EM_ NO2” – 2019 annual emissions of NOx (gram).

“EM_PM” – 2019 annual emissions of NOx (gram).

EPISODE output files for atmospheric concentration files are given on NetCDF file format.  Concentrations are given as annual average grid concentration for each of the components. In addition, 42 000  spatially spread out receptor points gives the 2 meter concentrations to allow for surface air concentration levels at individual point locations. Furthermore, these allows for downgridding concentrations to higher resolution.

The source contribution files are from EPISODE and gives atmospheric concentration fields for NOx, PM10 and PM2.5 from individual sources. The individual sources are

“RDU” -Road dust (PM only)

“EXT” – Exhaust  (PM only)

“TRA” - Exhaust  (NOx only)

“IND” – Industry

“RES” – Residential

“OTH” – Other (all other sources within the domain combined )

“BGC” – Background (all sources outside the domain combined )

## 引言

本数据集源自CoMobility项目，面向波兰大华沙地区打造。数据集包含与该区域交通活动、排放、空气质量及相关健康研究相关的各类数据。文件涵盖单个道路路段层面的道路属性、交通流量、高峰时段延误，以及道路交通产生的氮氧化物（NOx）、二氧化氮（NO2）和颗粒物（PM）排放数据。此外还包含分辨率为500米的网格化地表空气浓度数据，覆盖PM2.5、PM10、NOx及NO2。

## 数据生产

道路数据源自宏观交通模型MTAW（Warsaw Municipality, 2016）（波兰语全称Model Transportowy Aglomeracji Warszawskiej）。该模型基于2015年华沙综合出行调查开发，是大华沙地区的核心战略交通模型，最近一次修订于2019年。

由挪威国际气候与环境研究中心（NILU）开发的NERVE模型（Grythe等，2022）可针对道路交通精准估算温室气体与空气污染物排放。该模型采用自下而上的研究方法，整合区域交通模型（RTM）、机动车车队构成数据，以及源自《道路运输排放因子手册》（HBEFA）的排放因子。NERVE可配置为在多种尺度下开展排放计算，涵盖道路链接、行政区或国家级尺度。研究人员与政策制定者可利用该模型开展环境评估、政策制定及构建各类排放情景。其极高的细节精度不仅使其适用于实际排放估算，同时也是极具价值的研究工具。

其他来源的排放数据源自波兰环境保护与国家研究所（IEP-NRI）的中央排放数据库（Gawuc等，2021）。背景浓度数据取自哥白尼大气监测服务（CAMS）2019年集合预报结果（Marécal等，2015）。

由NILU开发的EPISODE模型（Hamer等，2020）是一款欧拉型城市扩散模型，旨在满足精准城市空气质量模型的需求，以支撑政策制定、规划编制与空气质量管控工作。EPISODE以三维网格模型形式运行，耦合数值天气预报（NWP）数据。该模型可模拟从点源、线源到受体点位的污染物扩散过程，重点关注城市区域臭氧的光化学生成。该模型的CityChem扩展模块集成了数值化学求解器、亚网格光化学模块与简化街道峡谷模型，可提升其处理复杂污染源的能力。EPISODE是理解与管控城市环境空气质量的重要工具。

## 数据文件

道路交通数据涵盖覆盖大华沙地区的60084条道路链接。输入文件源自MTAW模型的交通文件，经NERVE模型处理并格式化。文件格式为ESRI形状文件（ESRI shapefile），包含以下道路参数：

- "DISTANCE"：道路路段长度，单位为千米
- "CAPACITY"：道路小时通行能力
- "SLOPE"：道路纵向坡度，单位为百分比
- "SPEEDLIM"：道路法定限速，单位为千米每小时

此外还包含以下交通流量参数：

- "ADT_LIGHT"：轻型车辆（私家车+轻型货车）年度日平均交通量，基于2019年早晚高峰时段数据计算得出
- "ADT_HEAVY"：重型车辆年度日平均交通量，基于2019年数据计算得出
- "ADT_BUSES"：公共交通巴士年度日平均交通量，基于2019年数据计算得出
- "MRN_delay"：早高峰时段延误率，单位为百分比
- "EVE_delay"：晚高峰时段延误率，单位为百分比

文件同时包含以下年度排放数据：

- "EM_NOx"：2019年NOx年度排放量，单位为克
- "EM_NO2"：2019年NO2年度排放量，单位为克
- "EM_PM"：2019年PM年度排放量，单位为克

EPISODE输出的大气浓度文件采用NetCDF格式，数据为各污染物组分的年度平均网格浓度。此外，数据集包含42000个空间离散的受体点位数据，提供2米高度处的空气浓度，可用于获取单个点位的地表空气浓度水平。同时，该数据支持将浓度数据降尺度至更高分辨率。

源贡献文件源自EPISODE模型，提供各污染源对应的NOx、PM10及PM2.5大气浓度场。各污染源类别如下：

- "RDU"：道路扬尘（仅PM组分）
- "EXT"：尾气排放（仅PM组分）
- "TRA"：尾气排放（仅NOx组分）
- "IND"：工业源
- "RES"：居民源
- "OTH"：其他源（研究区域内所有其他污染源的总和）
- "BGC"：背景源（研究区域外所有污染源的总和）