SMART CITIES: Air Quality Monitoring
Due to its high impact over the public health, air pollution is becoming one of the main threats for urban societies. Besides the laws and efforts to reduce the pollutants emissions, technicians and administrators are working hard to develop alert systems aiming to protect the more vulnerable citizens during high pollution episodes. A key tool for that purpose are the reliable air pollution measurements. Nowadays, the latest developments in air monitoring sensors and its price reduction open the door to the deployment of dense wireless networks of sensors, installed in buildings, which may provide high resolution and accurate air pollution maps in highly populated areas. Next step, in order to reduce costs and to improve performances is to be able to locate sensors in moving platforms. This approach allows to acquire data also in whole neighborhoods but with a limited number of sensors.
Together with the M2M CTTC’s department we’ve developed the Crowdsourced Air Quality Monitoring (C-AQM) system, which has been designed to generate high-resolution air quality maps using data from crowdsourced sensors, reference stations and Copernicus. In the paper we shortly review the design and implementation of C-AQM: a low-cost, long lifetime battery-powered, light-weight and small form-factor device, equipped with NO2 gas sensors, GNSS receiver and radio communications interface for Low Power Wide Area Networks (LPWA), (i.e., Narrow Band-IoT).
In order to ensure good system performance, the C-AQM system uses information not only from the sensors included in the moving devices, but also from public data like national/regional reference measurements. The system has been deployed in the cities of Sabadell, Castelldefels and Barcelona, and several tests have been carried out. All the data provided by these sources is introduced in a bundle adjustment post-processing algorithm able to properly provide, with one-meter accuracy, the NO2 air quality measurements.
Figure. Air Quality Map of a pilot test in Sabadell. Data collected on the November 21st between 7:30 and 8:30 a.m.
SMART CITIES: Accessibility maps
Accessible cities with accessible services are an old claim of people with reduced mobility. But this demand is still far away of becoming a reality as lot of work is required to be done yet. First step towards accessible cities is to know about real situation of the cities and its pavement infrastructure. Detailed maps or databases on street slopes, access to sidewalks, mobility in public parks and gardens, etc. are required. In this paper, we propose to use smartphone based photogrammetric point clouds, as a starting point to create accessible maps or databases. Our research analyses the performance of these point clouds and the complexity of the image acquisition procedure required to obtain them. The research indicates, through two test cases, that smartphone technology is an economical and feasible solution to get the required information, which is quite often seek by city planners to generate accessible maps. The proposed approach paves the way to generate, in a near term, accessibility maps through the use of point clouds derived from crowdsourced smartphone imagery.
E. Angelats, M. E. Parés, P. Kumar, Feasibility of smartphone based photogrammetric point clouds for the generation of accesibility maps , in Proceedings of the International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLII-2, 2018. ISPRS TC II Mid-term Symposium “Towards Photogrammetry 2020″, 4–7 June 2018, Riva del Garda (Italy).