diff --git a/src/Environment/atmosphere.hxx b/src/Environment/atmosphere.hxx
index 1ee4e1b6b..466cba270 100644
--- a/src/Environment/atmosphere.hxx
+++ b/src/Environment/atmosphere.hxx
@@ -31,8 +31,6 @@
 #include <cmath>
 #include <utility>
 
-using namespace std;
-
 /**
  * Model the atmosphere in a way consistent with the laws
  * of physics.