diff --git a/sample/particles/main.ts b/sample/particles/main.ts
index c736800f..a2e7ebec 100644
--- a/sample/particles/main.ts
+++ b/sample/particles/main.ts
@@ -318,7 +318,7 @@ let numMipLevels = 1;
 const simulationParams = {
   simulate: true,
   deltaTime: 0.04,
-  toneMappingMode: 'standard',
+  toneMappingMode: 'standard' as GPUCanvasToneMappingMode,
   brightnessFactor: 1.0,
 };