We propose a framework for simulating the individual-specific exposure as an indicator for the environmental quality of urban regions. Adopting the perspective of a moving individual we combined maps of urban temperature with algorithms simulating human mobility. The former were derived from thermal-scan data gathered with an aeroplane and calibrated with air temperatures observed at 1.5 m height. The agent-based mobility models utilize different forms of random movement and agenda-driven movement and comprise potential field controlled walk (PTW), reference point mobility model (RPM), RPM with a pre-defined daily agenda of targets (RPMA), and truncated Lévy flights (TLF).

Defining the distribution of exposure increments (temperature exposure at every time step; in K/min) as an indicator, we studied its dependence on both mobility and urban spatial temperature distribution by help of simulation models. We found that the mobility algorithms PTW and TLF can generate non-ergodic trajectories, i.e., a runner performing many consecutive journeys and an ensemble of walkers have different distributions of exposure increments. Thus, the temperature-exposure of individuals highly depends on their mobility patterns. This result is consistent with a previous benzene-study that generated likewise very different levels of personal exposure depending on the type of mobility. For both maps the PTW algorithm has the potential to generate unique movement patterns that can result in individual-specific exposure.

A conclusion is that the temperature recorded by mobile receptors is a suitable indicator for the thermal exposure of people living in an urban region. Heat maps may show significant differences with respect to individual exposure. The cumulative distribution of temperature exposure provides information about the hazard of heat for individuals living in the studied environment. We suggest mobile measurements for an exploration of the urban environment, as they involve individual-specific mobility in a natural way and provide records of how much of an environmental agent arrives directly at human receptors.