Air pollution is a contributor to approximately one in every nine deaths annually. Air quality
monitoring is being carried out extensively in urban environments. Currently, however, city
air quality stations are expensive to maintain resulting in sparse coverage and data is not
readily available to citizens. This can be resolved by city-wide participatory sensing of air
quality fluctuations using low-cost sensors. We introduce new concepts for participatory
sensing: a voluntary community-based monitoring data forum for stakeholders to manage
air pollution interventions; an automated system (cyber-physical system) for monitoring
outdoor air quality and indoor air quality; programmable platform for calibration and
generating virtual sensors using data from low-cost sensors and city monitoring
stations. To test our concepts, we developed a low-cost sensor to measure
particulate matter (PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone
(O3) with GPS. We validated our approach in Helsinki, Finland, with participants carrying
the sensor for 3 months during six data campaigns between 2019 and 2021. We
demonstrate good correspondence between the calibrated low-cost sensor data and
city’s monitoring station measurements. Data analysis of their personal exposure was
made available to the participants and stored as historical data for later use. Combining the
location of low cost sensor data with participants public profile, we generate proxy
concentrations for black carbon and lung deposition of particles between districts, by
age groups and by the weekday.