The concentration of heavy metals in the air occurs when there are unpaved roads and in the case of AWKA it was a city of many blacksmiths who work iron and bronze, and there may be heavy metals in the particulate material generated by the wind. What would have to be estimated is whether they are PM10or o PM2.5 particles which are highly harmful to the respiratory system.
The road dust encountered in Awka metropolis is not unusual especially if there are a lot of untarred road links. The dust may contain heavy metals which are commonly present in the soil naturally. Their concentrations can be ascertained by carrying out analyses of composite samples using spectrometric methods such as AAS, GC-MS, ICP-OES, ICP-MS, and others..