City employees monitor air quality during their normal working routine


Cities have a lot of assets to attract young and active citizens, i.e. young families with children. However, these people are often concerned by the quality of the urban air. Air quality is therefore a major concern for city authorities.

IDEA has developed a platform that allows cities to collect detailed air quality data taking advantage of the fact that some of their employees carry out a large part of their daily work while moving on foot or on a bicycle in the outdoor urban environment.

Several studies have demonstrated that exposure of people to air pollution is poorly described by official stationary air quality monitoring stations at fixed locations. In an urban environment air quality can differ significantly from street to street, depending on traffic intensity and street lay-out (e.g. street canyons, narrow streets with high buildings on both sides).

Mobile measurements are complementary to these stationary air quality measurements.They can provide the necessary information of local air quality at street level. However, portable air quality monitors are still expensive and a lot of repeated trips have to be made to collect a representative amount of data. Opportunistic data collection allows to collect a huge number of data with limited additional efforts or costs. E.g. city guards, street sweepers, parking guards, postmen, …, they all carry out  a large part of their daily work while moving on foot or on a bicycle in the outdoor urban environment. IDEA makes use of this opportunity to turn these people into human air quality probes. The mobile measurement platform is designed for maximum autonomy and continuity, and minimal intervention of the person carrying out the measurements.


IDEA’s innovation and strengths

IDEA developed methods and software to collect the data and to process them into air quality maps. This is based on intensive trials to assess street-level variability in air quality using mobile measurements.

Before the measurement data is ready for the construction of air quality maps, a number of automated data pre-processing steps have to be executed. Currently, the automated data pre-processing chain contains four processing steps. In the first step, the measurements are enhanced where possible. This includes interpolation and flagging of lacking GPS locations and noise reduction of the microAethalometer black carbon measurements. In the second step, the data is validated by removing incorrect measurements. During the third data pre-processing step, mobile air quality measurements are corrected for available background concentrations. In the last step, the measurements are spatially aggregated for each road segment.



Detailed description of the demonstrator

The mobile measurement platform will be demonstrated and validated in collaboration with city guards of the city of Antwerp. The city guards monitor squares, streets and public spaces. On average they are 6 hours per day on the road carrying out surveillance tours, home visits and supervision at events. They are moving on foot or on bike, sometimes taking public transport.

Starting from 1st of July 3 teams of city guards are equipped with an easy-to-carry air quality monitor (which measures black carbon) and a GPS which they wear on a waist belt. The teams will carry the air quality monitor with them everywhere they go for 6 months. After every days work they connect the air quality monitor and the GPS to a ‘home station’ at their work location, and they start up the home station software. Data are downloaded automatically to the home station and sent to a database, and batteries are recharged.

All collected data are aggregated into a street-level air quality map. As more data are collected a map with an increasing level of detail is drawn. A density map indicates which areas are well covered and which aren’t.  Additional dedicated data collection efforts can target areas that are poorly covered. Individual measured tracks are not displayed systematically because their informative value is limited or even misleading.





Prof. Dr. Ir. Dick Botteldooren
+32 (0) 9 264 99 68

Technologiepark-Zwijnaarde 126, 9052 Gent



©IDEA-Project 2009

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