An $acyclic$ edge coloring of a graph is a proper edge coloring such that
there are no bichromatic cycles. The \emph{acyclic chromatic index} of a graph
is the minimum number k such that there is an acyclic edge coloring using k
colors and is denoted by $a'(G)$. It was conjectured by Alon, Sudakov and Zaks
(and much earlier by Fiamcik) that $a'(G)\le \Delta+2$, where $\Delta
=\Delta(G)$ denotes the maximum degree of the graph.

If every induced subgraph $H$ of $G$ satisfies the condition $\vert E(H)
\vert \le 2\vert V(H) \vert -1$, we say that the graph $G$ satisfies $Property\
A$. In this paper, we prove that if $G$ satisfies $Property\ A$, then $a'(G)\le
\Delta + 3$. Triangle free planar graphs satisfy $Property\ A$. We infer that
$a'(G)\le \Delta + 3$, if $G$ is a triangle free planar graph. Another class of
graph which satisfies $Property\ A$ is 2-fold graphs (union of two forests).