# Balancing the reaction equation for the oxidation of lead(II) sulfide with ozone

While I was reading about the chemical reactions of ozone, I came across this reaction. $$\ce{PbS + 4O3 -> PbSO4 + 4O2}$$

Though the reaction seems well balanced, but when I attempted to balance it myself, I did this as $$\ce{PbS + 2O3 -> PbSO4 + O2}$$

I understand that there must be some reason that the 1st reaction is given in the book. I'm just not able to figure out why.

Can somebody give an explanation as to why is it so?

$\ce{PbS + 4O3 -> PbSO4 + 4 O2}$
$\ce{3PbS + 4O3 -> 3PbSO4 }$