Table 1 Comparison of alternatives to the base case proposed in this article

Base case in this article

Pollution field is calculated by the aggregate of individual GSM or GPS-based trajectories plus emission and dispersion models.

Accumulated along individual GSM or GPS-based trajectories.

Low cost per individual. Cost of computational power.

Alternative 1

Measured on each individual trajectory by people carrying environmental micro-sensors.

Accumulated along individual GPS-based trajectories.

High cost per individual. Additional cost per individual is roughly the cost of a new smart phone.

Alternative 2

Stationary monitoring network plus geo-statistics modelling.

Accumulated along GSM or GPS-based trajectories.

Very high investment cost. Need very high density of monitoring stations on the road network.