diff --git a/examples/webgl_custom_attributes_particles3.html b/examples/webgl_custom_attributes_particles3.html
index cace8397b9e0413028e7610ba73d844c16153a85..830c37a4572afa0acb81283008d4efecd5bd4434 100644
--- a/examples/webgl_custom_attributes_particles3.html
+++ b/examples/webgl_custom_attributes_particles3.html
@@ -270,7 +270,7 @@
 			for( var i = 0; i < attributes.size.value.length; i ++ ) {
 
 				if ( i < vc1 )
-					attributes.size.value[ i ] = 26 + 32 * Math.sin( 0.1 * i + 0.6 * time );
+					attributes.size.value[ i ] = Math.max(0, 26 + 32 * Math.sin( 0.1 * i + 0.6 * time ));
 
 
 			}