check if current 'page' is a node type of blog

gistfile1.php

<?php

//check if pg is node
if (arg(0) == 'node') {
  $nid = arg(1);
  //load current node
  if ($nid) {
    $node = node_load($nid);
    
    if($node->type == 'blog') {
      //do something here.
    }
  }
}