Air Quality Network Pilot Progressing in Nanjing

The construction work to build up a new air quality network pilot in the city of Nanjing in the Yangtze River Delta in China is progressing at a good pace. Last year, Vaisala announced a project to build a groundbreaking air quality network pilot in Nanjing . The project is a joint Sino-Finnish co-operation project led by Vaisala. Partners in the project are the Finnish Meteorological Institute, and the Institute for Atmospheric and Earth System Research (INAR) in the University of Helsinki. In China, the project is led by Nanjing University (NJU) with Kunshan Yangchen Langdu Environment Institute Ltd. and Climblue Technology Ltd. as business partners. The project will establish a pilot for next-generation pollution monitoring and modeling employing several new approaches to ambient air quality monitoring.

First Sensors in Place Before Ministerial Visit

The first Vaisala AQT420 air quality sensors are now in place at locations that provide new and interesting information about the variation of local air quality in Nanjing. Further sensors will be installed in the city center, in the proximity of the roads with heavy traffic, and in the industrial and urban areas of the city. The goal is to understand the formation of the pollution from different sources including long-range transportation.

One of the highlights of the project took place on September 14 when the delegation of Kimmo Tiilikainen, the Finnish Minister of Environment, Energy and Housing, visited Nanjing University and the Air Quality Testbed project. Minister Tiilikainen was impressed by the project achievements and thanked the partners for the concrete outcomes. It was jointly concluded that only with the unique knowhow of both the Chinese and Finnish project partners is it possible to create a concept that could be also copied for global markets. 

Enabling Relevant Air Quality Forecasts

The pilot covers Vaisala´s new compact air quality sensors, AQT420, to monitor critical pollution gases (NO₂, O₃, CO, SO₂) and particulates (PM2.5 and PM10) Additionally, the pilot includes Vaisala´s multi-weather sensors (WXT530) to monitor the weather conditions, such as wind and rain, within the air quality monitoring sites.

The project also introduces a 3D component into air quality monitoring by providing online information about the boundary layer height and vertical profile through Vaisala ceilometers (CL51). Together with pollution emission sources, weather influences, and long-range transportation and deposition, boundary layer height is a key parameter for the characterization of air quality.

All data is gathered to a new high-resolution air quality modeling tool, FMI-ENFUSER, developed by the Finnish Meteorological Institute. ENFUSER is a unique air quality modeling system that combines traditional dispersion modeling with modern data fusion technologies. It fuses various datasets to model and forecast air quality in very high resolution down to the street block level (appr. 12 meters). The forecasts are provided for 72 hours. The project also uses high-end air quality data from Nanjing’s SORPES station (Station for Observing Regional Processes of the Earth System) and mobile SORPES. The data from SORPES provides unique possibilities for advanced research, sensor data verification, and network optimization.

The Yangtze river flowing through the city has an important role in understanding the complex air quality picture of the city: the river is one of the world’s most populated rivers calculated by amount of ships. As the ships are known to be significant pollutants, the river has a huge impact to the city´s air quality. This was also confirmed while producing the first heatmaps of the ENFUSER model: the model can also include ship emissions based on FMI´s STEAM ship emission model.