In this paper, we propose a sharp and quantitative criterion, which focuses solely on $Q$ curvature, to demonstrate the Chern-Gauss-Bonnet integral. In contrast to the previous results [4,5,10], we use a new approach that involves estimating the singular integral. Furthermore, we derive the asymptotic formula for the solution to the general $Q$ curvature equation.
Comment: We remove the nonnegative assumption of Q curvature in the main Theorem and fix some typos. 25 pages