diff --git a/employee-app/health-monitor/environment/device-detail.html b/employee-app/health-monitor/environment/device-detail.html
index e66fe8e..6ef5ecf 100644
--- a/employee-app/health-monitor/environment/device-detail.html
+++ b/employee-app/health-monitor/environment/device-detail.html
@@ -314,7 +314,7 @@ function genTrend(metricName, period) {
     'TDS':{range:[100,850],unit:'mg/L'}
   };
 
-  if (configs[metricName]) return { metricName: metricName, cfg: configs[metricName], period: period };
+  if (configs[metricName]) return { metricName: metricName, cfg: configs[metricName], period: period, unit: '' };
 
   var r = ranges[metricName];
   if (!r) r = { range: [10, 100], unit: '' };
@@ -345,6 +345,7 @@ function genTrend(metricName, period) {
 
   return {
     metricName: metricName,
+    unit: r.unit || '',
     isAQI: false, yMax: maxVal, yTicks: Array.from({length: yTicks+1}, function(_, i) {
       var v = maxVal / yTicks * i;
       return r.unit === 'mg/m³' ? +v.toFixed(2) : Math.round(v);