Help with DFRobot Sound Meter for noise pollution project

Hi everyone,

I'm working on a community-based project to measure noise pollution in busy neighborhoods in the city that I live in.

I'm using the DFRobot Analog Sound Level Meter (SKU:SEN0232) connected to an ESP8266 node-mcu module to send results to a central database.

The sensor works pretty well out of box. We're using the code as is. But there is one problem: sensitivity.

For example, if I am in a very quiet room and just exhale from my mouth the sound level jumps to 100+ decibels. In a semi-quiet room the levels are between 60-70 DB.

When benchmarking with very good decibel meter applications on our phone, these values seem to be very high.  

My question is, can someone please explain to me if I am missing something here. Should we tweak the code of the sound level meter to make it less sensitive (e.g. lower the sensitivity constant from 50 to 25) or are these reading in fact genuine?

Thank you very much for any help you can provide!