Answer:
This is a typical wrong believe that a jackhammer has 110 dB, a rock band has at least 115 dB and a bullhorn must have 120 dB. Every one seems to be content with these wrong numbers.
If there is no given distance with the measured decibel value, such numbers are really nonsense.
With doubling the distance from a sound source the decibels decrease by 6 dB.
So a bullhorn sound can be at 12.5 m distance 130 dB. At 25 m distance 124 dB, at 50 m distance 118 dB and at 100 m distance only 114 dB.
You see how important it is to tell always the distance with the measured decibel level. Don't believe that only a specific decibel value belongs to noise source, like here the bullhorn.