This research further investigates the recently introduced (in [4]) paradigm of radiation awareness in ambient environments with abundant heterogeneous wireless networking from a distributed computing perspective. We call radiation at a point of a wireless network the total amount of electromagnetic quantity the point is exposed to; our denition incorporates the eect of topology as well as the time domain and environment aspects. Even if the impact of radiation to human health remains largely unexplored and controversial, we believe it is worth trying to understand and control, in a way that does not decrease much the quality of service oered to users of the wireless network. In particular, we here focus on the fundamental problem of ecient data propagation in wireless sensor networks, try- ing to keep latency low while maintaining at low levels the radiation cumulated by wireless transmissions. We rst propose greedy and oblivious routing heuristics that are radiation aware. We then combine them with temporal back-o schemes that use local properties of the network (e.g. number of neighbours, distance from sink) in order to spread" radiation in a spatio-temporal way. Our proposed radiation aware routing heuristics succeed to keep radiation levels low, while not increasing latency.