diff --git a/airup-sdk/src/files/service.rs b/airup-sdk/src/files/service.rs
index 8786fe4..9b2bf6b 100644
--- a/airup-sdk/src/files/service.rs
+++ b/airup-sdk/src/files/service.rs
@@ -112,7 +112,7 @@ pub struct Env {
     ///
     /// By default, the service runs with the same environment variables as `airupd`.
     #[serde(default)]
-    pub vars: HashMap<String, Option<String>>,
+    pub vars: HashMap<String, toml::Value>,
 }
 impl Default for Env {
     fn default() -> Self {
diff --git a/airup-sdk/src/files/system_conf.rs b/airup-sdk/src/files/system_conf.rs
index 31a813c..5467305 100644
--- a/airup-sdk/src/files/system_conf.rs
+++ b/airup-sdk/src/files/system_conf.rs
@@ -37,7 +37,7 @@ pub struct Env {
     ///
     /// If a value is set to `null`, the environment variable gets removed if it exists.
     #[serde(default)]
-    pub vars: HashMap<String, Option<String>>,
+    pub vars: HashMap<String, toml::Value>,
 }
 
 fn default_os_name() -> String {
diff --git a/airupd/src/storage/config.rs b/airupd/src/storage/config.rs
index d328c92..816097a 100644
--- a/airupd/src/storage/config.rs
+++ b/airupd/src/storage/config.rs
@@ -36,7 +36,11 @@ impl Config {
             vars.insert(k.to_owned(), v.as_ref().map(Into::into));
         }
         for (k, v) in &self.system_conf.env.vars {
-            vars.insert(k.into(), v.clone());
+            if v.as_integer() == Some(0) {
+                vars.insert(k.clone(), None);
+            } else if let Some(s) = v.as_str() {
+                vars.insert(k.clone(), Some(s.into()));
+            }
         }
         airupfx::env::set_vars(vars);
     }
diff --git a/airupd/src/supervisor/task/mod.rs b/airupd/src/supervisor/task/mod.rs
index b200029..2f3bfbf 100644
--- a/airupd/src/supervisor/task/mod.rs
+++ b/airupd/src/supervisor/task/mod.rs
@@ -197,6 +197,23 @@ async fn ace_environment(
         airup_sdk::files::service::Stdio::Log => log(y),
     };
 
+    let vars = env
+        .vars
+        .iter()
+        .filter(|(_, v)| v.as_integer() == Some(0) || v.is_str())
+        .map(|(k, v)| {
+            (
+                k.into(),
+                if v.is_integer() {
+                    None
+                } else if let Some(s) = v.as_str() {
+                    Some(s.into())
+                } else {
+                    unreachable!()
+                },
+            )
+        });
+
     result
         .login(env.login.as_deref())?
         .uid(env.uid)
@@ -205,7 +222,7 @@ async fn ace_environment(
         .stdout(to_ace(env.stdout.clone(), 1))
         .stderr(to_ace(env.stderr.clone(), 2))
         .clear_vars(env.clear_vars)
-        .vars::<String, _, String>(env.vars.clone().into_iter())
+        .vars::<String, _, String>(vars)
         .working_dir::<PathBuf, _>(env.working_dir.clone())
         .setsid(true);