  As urbanization proceeds at an astonishing rate, cities have to continuously
improve their solutions that affect the safety, health and overall wellbeing of
their residents. Smart city projects worldwide build on advanced sensor,
information and communication technologies to help dealing with issues like air
pollution, waste management, traffic optimization, and energy efficiency. The
paper reports about the prototype of a smart city initiative in Budapest which
applies various sensors installed on the public lighting system and a
cloud-based analytical module. While the installed wireless multi-sensor
network gathers information about a number of stressors, the module integrates
and statistically processes the data. The module can handle inconsistent,
missing and noisy data and can extrapolate the measurements in time and space,
namely, it can create short-term forecasts and smoothed maps, both accompanied
by reliability estimates. The resulting database uses geometric representations
and can serve as an information centre for public services.
