diff --git a/CHANGELOG.md b/CHANGELOG.md
index 539dbda..25f133e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,21 @@
 # CHANGELOG
 
+## tmp v0.2.1
+
+- [#250](https://github.com/raszi/node-tmp/issues/250)
+
+  ***FEATURE***
+  
+  New option `tmpdir` that allows users to override the system's tmpdir.
+  
+  ```
+  tmp.dirSync({tmpdir: '/mnt/tmp'});
+  ```
+  
+  ***BUG FIX***
+  
+  Changes to options will no longer leak out.
+  
 ## tmp v0.2.0
 
 - drop support for node version < v8.17.0
diff --git a/README.md b/README.md
index 2e5572e..bb20fb7 100644
--- a/README.md
+++ b/README.md
@@ -350,6 +350,7 @@ All options are optional :)
      absolute paths are fine as long as they point to a location under the system's default temporary directory.
      Any directories along the so specified path must exist, otherwise a ENOENT error will be thrown upon access, 
      as tmp will not check the availability of the path, nor will it establish the requested path for you.
+  * `tmpdir`: allows you to override the system's root tmp directory
   * `tries`: how many times should the function try to get a unique filename before giving up, default `3`
   * `keep`: signals that the temporary file or directory should not be deleted on exit, default is `false`
     * In order to clean up, you will have to call the provided `cleanupCallback` function manually.
diff --git a/docs/global.html b/docs/global.html
index e225ad4..a203ace 100644
--- a/docs/global.html
+++ b/docs/global.html
@@ -908,7 +908,7 @@ <h4 class="name" id="setGracefulCleanup"><span class="type-signature"></span>set
     
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line630">line 630</a>
+        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line654">line 654</a>
     </li></ul></dd>
     
 
@@ -1434,7 +1434,7 @@ <h5>Parameters:</h5>
     
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line713">line 713</a>
+        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line739">line 739</a>
     </li></ul></dd>
     
 
@@ -1522,7 +1522,7 @@ <h4 class="name" id="cleanupCallbackSync"><span class="type-signature"></span>cl
     
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line720">line 720</a>
+        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line746">line 746</a>
     </li></ul></dd>
     
 
@@ -1729,7 +1729,7 @@ <h5>Parameters:</h5>
     
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line699">line 699</a>
+        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line725">line 725</a>
     </li></ul></dd>
     
 
@@ -1936,7 +1936,7 @@ <h5>Parameters:</h5>
     
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line706">line 706</a>
+        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line732">line 732</a>
     </li></ul></dd>
     
 
@@ -2093,7 +2093,7 @@ <h5 class="subsection-title">Properties:</h5>
     
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line671">line 671</a>
+        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line697">line 697</a>
     </li></ul></dd>
     
 
@@ -2317,7 +2317,7 @@ <h5>Parameters:</h5>
     
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line683">line 683</a>
+        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line709">line 709</a>
     </li></ul></dd>
     
 
@@ -2555,7 +2555,7 @@ <h5>Parameters:</h5>
     
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line691">line 691</a>
+        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line717">line 717</a>
     </li></ul></dd>
     
 
@@ -2735,7 +2735,7 @@ <h5 class="subsection-title">Properties:</h5>
     
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line664">line 664</a>
+        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line690">line 690</a>
     </li></ul></dd>
     
 
@@ -2978,7 +2978,7 @@ <h5 class="subsection-title">Properties:</h5>
 
             
 
-            <td class="description last">tmp directory relative to the system tmp directory to use</td>
+            <td class="description last">tmp directory relative to the root tmp directory in use</td>
         </tr>
 
     
@@ -3045,6 +3045,37 @@ <h5 class="subsection-title">Properties:</h5>
 
     
 
+        <tr>
+            
+                <td class="name"><code>tmpdir</code></td>
+            
+
+            <td class="type">
+            
+                
+<span class="param-type">string</span>
+
+
+            
+            </td>
+
+            
+                <td class="attributes">
+                
+
+                
+                    &lt;nullable><br>
+                
+                </td>
+            
+
+            
+
+            <td class="description last">the root tmp directory which overrides the os tmpdir</td>
+        </tr>
+
+    
+
         <tr>
             
                 <td class="name"><code>unsafeCleanup</code></td>
@@ -3172,7 +3203,7 @@ <h5 class="subsection-title">Properties:</h5>
     
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line647">line 647</a>
+        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line672">line 672</a>
     </li></ul></dd>
     
 
@@ -3246,7 +3277,7 @@ <h4 class="name" id="simpleCallback"><span class="type-signature"></span>simpleC
     
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line726">line 726</a>
+        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line752">line 752</a>
     </li></ul></dd>
     
 
@@ -3429,7 +3460,7 @@ <h5>Parameters:</h5>
     
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line677">line 677</a>
+        <a href="tmp.js.html">tmp.js</a>, <a href="tmp.js.html#line703">line 703</a>
     </li></ul></dd>
     
 
@@ -3479,7 +3510,7 @@ <h2><a href="index.html">Home</a></h2><h3>Global</h3><ul><li><a href="global.htm
 <br class="clear">
 
 <footer>
-    Documentation generated by <a href="https://github.com/jsdoc/jsdoc">JSDoc 3.6.3</a> on Sat Feb 08 2020 01:04:48 GMT+0100 (GMT+01:00)
+    Documentation generated by <a href="https://github.com/jsdoc/jsdoc">JSDoc 3.6.3</a> on Tue Apr 28 2020 21:08:40 GMT+0200 (GMT+02:00)
 </footer>
 
 <script> prettyPrint(); </script>
diff --git a/docs/index.html b/docs/index.html
index 2748241..b779604 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -296,6 +296,7 @@ <h2>Options</h2>
 absolute paths are fine as long as they point to a location under the system's default temporary directory.
 Any directories along the so specified path must exist, otherwise a ENOENT error will be thrown upon access,
 as tmp will not check the availability of the path, nor will it establish the requested path for you.</li>
+<li><code>tmpdir</code>: allows you to override the system's root tmp directory</li>
 <li><code>tries</code>: how many times should the function try to get a unique filename before giving up, default <code>3</code></li>
 <li><code>keep</code>: signals that the temporary file or directory should not be deleted on exit, default is <code>false</code>
 <ul>
@@ -322,7 +323,7 @@ <h2><a href="index.html">Home</a></h2><h3>Global</h3><ul><li><a href="global.htm
 <br class="clear">
 
 <footer>
-    Documentation generated by <a href="https://github.com/jsdoc/jsdoc">JSDoc 3.6.3</a> on Sat Feb 08 2020 01:04:48 GMT+0100 (GMT+01:00)
+    Documentation generated by <a href="https://github.com/jsdoc/jsdoc">JSDoc 3.6.3</a> on Tue Apr 28 2020 21:08:40 GMT+0200 (GMT+02:00)
 </footer>
 
 <script> prettyPrint(); </script>
diff --git a/docs/tmp.js.html b/docs/tmp.js.html
index 6552b27..b3bee29 100644
--- a/docs/tmp.js.html
+++ b/docs/tmp.js.html
@@ -380,7 +380,7 @@ <h1 class="page-title">Source: tmp.js</h1>
       if (index >= 0) _removeObjects.splice(index, 1);
 
       called = true;
-      if (sync || removeFunction === FN_RMDIR_SYNC || removeFunction == FN_RIMRAF_SYNC) {
+      if (sync || removeFunction === FN_RMDIR_SYNC || removeFunction === FN_RIMRAF_SYNC) {
         return removeFunction(fileOrDirName);
       } else {
         return removeFunction(fileOrDirName, next || function() {});
@@ -479,7 +479,13 @@ <h1 class="page-title">Source: tmp.js</h1>
     return [{}, callback];
   }
 
-  return [options, callback];
+  // copy options so we do not leak the changes we make internally
+  const actualOptions = {};
+  for (const key of Object.getOwnPropertyNames(options)) {
+    actualOptions[key] = options[key];
+  }
+
+  return [actualOptions, callback];
 }
 
 /**
@@ -491,7 +497,7 @@ <h1 class="page-title">Source: tmp.js</h1>
  */
 function _generateTmpName(opts) {
 
-  const tmpDir = _getTmpDir();
+  const tmpDir = opts.tmpdir;
 
   /* istanbul ignore else */
   if (!_isUndefined(opts.name))
@@ -508,8 +514,7 @@ <h1 class="page-title">Source: tmp.js</h1>
     process.pid,
     '-',
     _randomChars(12),
-    '-',
-    opts.postfix ? opts.postfix : ''
+    opts.postfix ? '-' + opts.postfix : ''
   ].join('');
 
   return path.join(tmpDir, opts.dir, name);
@@ -523,7 +528,11 @@ <h1 class="page-title">Source: tmp.js</h1>
  * @private
  */
 function _assertAndSanitizeOptions(options) {
-  const tmpDir = _getTmpDir();
+
+  options.tmpdir = _getTmpDir(options);
+
+  const tmpDir = options.tmpdir;
+
   /* istanbul ignore else */
   if (!_isUndefined(options.name))
     _assertIsRelative(options.name, 'name', tmpDir);
@@ -554,7 +563,7 @@ <h1 class="page-title">Source: tmp.js</h1>
   options.template = _isBlank(options.template) ? undefined : path.relative(options.dir, options.template);
 
   // for completeness' sake only, also keep (multiple) blanks if the user, purportedly sane, requests us to
-  options.name = _isUndefined(options.name) ? undefined : options.name;
+  options.name = _isUndefined(options.name) ? undefined : _sanitizeName(options.name);
   options.prefix = _isUndefined(options.prefix) ? '' : options.prefix;
   options.postfix = _isUndefined(options.postfix) ? '' : options.postfix;
 }
@@ -571,11 +580,26 @@ <h1 class="page-title">Source: tmp.js</h1>
  * @private
  */
 function _resolvePath(name, tmpDir) {
-  if (name.startsWith(tmpDir)) {
-    return path.resolve(name);
+  const sanitizedName = _sanitizeName(name);
+  if (sanitizedName.startsWith(tmpDir)) {
+    return path.resolve(sanitizedName);
   } else {
-    return path.resolve(path.join(tmpDir, name));
+    return path.resolve(path.join(tmpDir, sanitizedName));
+  }
+}
+
+/**
+ * Sanitize the specified path name by removing all quote characters.
+ *
+ * @param name
+ * @returns {string}
+ * @private
+ */
+function _sanitizeName(name) {
+  if (_isBlank(name)) {
+    return name;
   }
+  return name.replace(/["']/g, '');
 }
 
 /**
@@ -663,10 +687,11 @@ <h1 class="page-title">Source: tmp.js</h1>
  * Returns the currently configured tmp dir from os.tmpdir().
  *
  * @private
+ * @param {Options?} options
  * @returns {string} the currently configured tmp dir
  */
-function _getTmpDir() {
-  return path.resolve(os.tmpdir());
+function _getTmpDir(options) {
+  return path.resolve(_sanitizeName(options &amp;&amp; options.tmpdir || os.tmpdir()));
 }
 
 // Install process exit listener
@@ -681,9 +706,10 @@ <h1 class="page-title">Source: tmp.js</h1>
  * @property (?int) mode the access mode, defaults are 0o700 for directories and 0o600 for files
  * @property {?string} template the "mkstemp" like filename template
  * @property {?string} name fixed name relative to tmpdir or the specified dir option
- * @property {?string} dir tmp directory relative to the system tmp directory to use
+ * @property {?string} dir tmp directory relative to the root tmp directory in use
  * @property {?string} prefix prefix for the generated name
  * @property {?string} postfix postfix for the generated name
+ * @property {?string} tmpdir the root tmp directory which overrides the os tmpdir
  * @property {?boolean} unsafeCleanup recursively removes the created temporary directory, even when it's not empty
  * @property {?boolean} detachDescriptor detaches the file descriptor, caller is responsible for closing the file, tmp will no longer try closing the file during garbage collection
  * @property {?boolean} discardDescriptor discards the file descriptor (closes file, fd is -1), tmp will no longer try closing the file during garbage collection
@@ -760,7 +786,7 @@ <h1 class="page-title">Source: tmp.js</h1>
 
 // exporting all the needed methods
 
-// evaluate os.tmpdir() lazily, mainly for simplifying testing but it also will
+// evaluate _getTmpDir() lazily, mainly for simplifying testing but it also will
 // allow users to reconfigure the temporary directory
 Object.defineProperty(module.exports, 'tmpdir', {
   enumerable: true,
@@ -796,7 +822,7 @@ <h2><a href="index.html">Home</a></h2><h3>Global</h3><ul><li><a href="global.htm
 <br class="clear">
 
 <footer>
-    Documentation generated by <a href="https://github.com/jsdoc/jsdoc">JSDoc 3.6.3</a> on Sat Feb 08 2020 01:04:48 GMT+0100 (GMT+01:00)
+    Documentation generated by <a href="https://github.com/jsdoc/jsdoc">JSDoc 3.6.3</a> on Tue Apr 28 2020 21:08:40 GMT+0200 (GMT+02:00)
 </footer>
 
 <script> prettyPrint(); </script>
diff --git a/lib/tmp.js b/lib/tmp.js
index 4cb77cb..d458df6 100644
--- a/lib/tmp.js
+++ b/lib/tmp.js
@@ -352,7 +352,7 @@ function _prepareRemoveCallback(removeFunction, fileOrDirName, sync, cleanupCall
       if (index >= 0) _removeObjects.splice(index, 1);
 
       called = true;
-      if (sync || removeFunction === FN_RMDIR_SYNC || removeFunction == FN_RIMRAF_SYNC) {
+      if (sync || removeFunction === FN_RMDIR_SYNC || removeFunction === FN_RIMRAF_SYNC) {
         return removeFunction(fileOrDirName);
       } else {
         return removeFunction(fileOrDirName, next || function() {});
@@ -451,7 +451,13 @@ function _parseArguments(options, callback) {
     return [{}, callback];
   }
 
-  return [options, callback];
+  // copy options so we do not leak the changes we make internally
+  const actualOptions = {};
+  for (const key of Object.getOwnPropertyNames(options)) {
+    actualOptions[key] = options[key];
+  }
+
+  return [actualOptions, callback];
 }
 
 /**
@@ -463,7 +469,7 @@ function _parseArguments(options, callback) {
  */
 function _generateTmpName(opts) {
 
-  const tmpDir = _getTmpDir();
+  const tmpDir = opts.tmpdir;
 
   /* istanbul ignore else */
   if (!_isUndefined(opts.name))
@@ -494,7 +500,11 @@ function _generateTmpName(opts) {
  * @private
  */
 function _assertAndSanitizeOptions(options) {
-  const tmpDir = _getTmpDir();
+
+  options.tmpdir = _getTmpDir(options);
+
+  const tmpDir = options.tmpdir;
+
   /* istanbul ignore else */
   if (!_isUndefined(options.name))
     _assertIsRelative(options.name, 'name', tmpDir);
@@ -649,10 +659,11 @@ function setGracefulCleanup() {
  * Returns the currently configured tmp dir from os.tmpdir().
  *
  * @private
+ * @param {Options?} options
  * @returns {string} the currently configured tmp dir
  */
-function _getTmpDir() {
-  return path.resolve(_sanitizeName(os.tmpdir()));
+function _getTmpDir(options) {
+  return path.resolve(_sanitizeName(options && options.tmpdir || os.tmpdir()));
 }
 
 // Install process exit listener
@@ -667,9 +678,10 @@ process.addListener(EXIT, _garbageCollector);
  * @property (?int) mode the access mode, defaults are 0o700 for directories and 0o600 for files
  * @property {?string} template the "mkstemp" like filename template
  * @property {?string} name fixed name relative to tmpdir or the specified dir option
- * @property {?string} dir tmp directory relative to the system tmp directory to use
+ * @property {?string} dir tmp directory relative to the root tmp directory in use
  * @property {?string} prefix prefix for the generated name
  * @property {?string} postfix postfix for the generated name
+ * @property {?string} tmpdir the root tmp directory which overrides the os tmpdir
  * @property {?boolean} unsafeCleanup recursively removes the created temporary directory, even when it's not empty
  * @property {?boolean} detachDescriptor detaches the file descriptor, caller is responsible for closing the file, tmp will no longer try closing the file during garbage collection
  * @property {?boolean} discardDescriptor discards the file descriptor (closes file, fd is -1), tmp will no longer try closing the file during garbage collection
@@ -746,7 +758,7 @@ process.addListener(EXIT, _garbageCollector);
 
 // exporting all the needed methods
 
-// evaluate os.tmpdir() lazily, mainly for simplifying testing but it also will
+// evaluate _getTmpDir() lazily, mainly for simplifying testing but it also will
 // allow users to reconfigure the temporary directory
 Object.defineProperty(module.exports, 'tmpdir', {
   enumerable: true,
diff --git a/package.json b/package.json
index 73ce71a..6598609 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "tmp",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "description": "Temporary file and directory creator",
   "author": "KARASZI István <github@spam.raszi.hu> (http://raszi.hu/)",
   "contributors": [
diff --git a/test/inband-standard.js b/test/inband-standard.js
index 3096023..05eb8b3 100644
--- a/test/inband-standard.js
+++ b/test/inband-standard.js
@@ -2,12 +2,12 @@
 // vim: expandtab:ts=2:sw=2
 
 var
+  fs = require('fs'),
   path = require('path'),
   assertions = require('./assertions'),
   rimraf = require('rimraf'),
   tmp = require('../lib/tmp');
 
-
 module.exports = function inbandStandard(isFile, beforeHook, sync = false) {
   var testMode = isFile ? 0o600 : 0o700;
   describe('without any parameters', inbandStandardTests({ mode: testMode, prefix: 'tmp-' }, null, isFile, beforeHook, sync));
@@ -18,6 +18,7 @@ module.exports = function inbandStandard(isFile, beforeHook, sync = false) {
   describe('with name', inbandStandardTests({ mode: testMode }, { name: 'tmp-using-name' }, isFile, beforeHook, sync));
   describe('with mode', inbandStandardTests(null, { mode: 0o755 }, isFile, beforeHook, sync));
   describe('with multiple options', inbandStandardTests(null, { prefix: 'tmp-multiple', postfix: 'bar', mode: 0o750 }, isFile, beforeHook, sync));
+  describe('with tmpdir option', inbandStandardTests(null, { tmpdir: path.join(tmp.tmpdir, 'tmp-external'), mode: 0o750 }, isFile, beforeHook, sync));
   if (isFile) {
     describe('with discardDescriptor', inbandStandardTests(null, { mode: testMode, discardDescriptor: true }, isFile, beforeHook, sync));
     describe('with detachDescriptor', inbandStandardTests(null, { mode: testMode, detachDescriptor: true }, isFile, beforeHook, sync));
@@ -33,6 +34,14 @@ function inbandStandardTests(testOpts, opts, isFile, beforeHook, sync = false) {
     // topic reference will be created by the beforeHook
     const topic = { topic: null, opts: opts };
 
+    // hack for tmpdir option, otherwise the whole test shebang would have to be refactored
+    if (opts.tmpdir) {
+      if (!fs.existsSync(opts.tmpdir)) {
+        // let tmp cleanup the dir on process exit, also we do not care if it is left over
+        tmp.dirSync({name: path.relative(tmp.tmpdir, opts.tmpdir), unsafeCleanup: true});
+      }
+    }
+
     // bind everything to topic so we avoid global
     before(beforeHook.bind(topic));
 
@@ -61,7 +70,7 @@ function inbandStandardTests(testOpts, opts, isFile, beforeHook, sync = false) {
     }
 
     it('should have been created in the expected directory', function () {
-      assertions.assertDir(this.topic.name, testOpts.dir || opts.dir || tmp.tmpdir);
+      assertions.assertDir(this.topic.name, testOpts.dir || opts.dir || opts.tmpdir || tmp.tmpdir);
     }.bind(topic));
 
     if (opts.name) {