April 11, 2017

Welcome to Hush City  app!


Click here to download Hush City app on iTunes store!

Click here to download Hush City app on Google Play store!


With Hush City app, you are an active part of a citizen science research project to map and evaluate quietness in cities.

Our cities are becoming noisier by the hour. Only in Europe, over 125 million people are affected by noise pollution from traffic every year, and apparently, quietness is becoming a luxury available only to a few of us. By using this free mobile app, you will contribute to making quietness available to all those appreciate it.

Hush City app will help you to identify, access and evaluate “everyday quiet areas” in your neighborhoods. You can find places such as small, quiet spots where you can go to escape the city’s chaos, relax, read a book, play with your kids, and have a pleasant conversation. Chill out!

Join the community. It is simple.

  • Download Hush City app
  • Go to one of your favorite quiet spots
  • Record the sound where you are in the quiet spot
  • Take a picture of the spot where you recorded the sound
  • Answer the questionnaire about this quiet spot
  • Share this information with your community.

Or, use the app to find a quiet spot near to you. Go to it and enjoy spending some time there.

>>> Click here to download Hush City app’s User Guidelines!

* Please be aware that noise levels measured by the mobile app, may not be entirely accurate, depending on which smartphones are used, weather conditions and other factors.

Theoretical Framework

Only in Europe, over 125 million people are affected by noise pollution from traffic every year.
Noise from road traffic alone is the second most harmful environmental stressor in Europe, behind air pollution, according to the World Health Organization (WHO). The harmful effects of noise arise mainly from the stress reaction it causes in the human body, which can also occur during sleep. These can potentially lead to premature death, cardiovascular disease, cognitive impairment, sleep disturbance, hypertension and, at the least, annoyance (EEA, 2017). Along with negative impact on our health, well-being and quality of life, noise pollution’s effects cost us approximately 50/100 billion euros per year (DEGA seminar, 2017).

At the European policy level, in 2002 the European Environmental Noise Directive 2002/49/EC (END) was adopted with the aim of establishing a common approach to avoid, prevent, and reduce the harmful effects of noise pollution among the Members States. The END provides a quantitative methodology based upon acoustical indicators (“LAeq” and “Lden”) to measure noise pollution as sound pressure level, “noise maps” to represent it, and action plans based upon noise-mapping results. Furthermore, the END stresses the importance of protecting and planning urban quiet areas, and releases the definition of a “quiet area”. Finally, the END calls for informing and involving the public in preparing noise maps and action plans but it does not suggest any strategy to achieve this goal.

As reported in (Schulte-Fortkamp, Dubois, 2006; Licitra et al., 2011; Borchi, 2012; HOSANNA, 2013) the quantitative methodology provided by the END is insufficient to understand the complex nature of noise pollution as it does not consider the influence of people’s perception in the evaluation of the sonic environment, particularly in its characteristic of “quietness”.

In order to compensate this deficiency, in the past decades the soundscape approach has been developed in diverse disciplinary fields by researchers in Europe and beyond who referred to the early concepts from the 1960’s by R. M. Schafer and by the World Soundscape Project group (Karlsson, 2000). Recently, this approach has been proved by the COST Group on Soundscape to be essential to improve the quality of life in urban areas, with regard to noise pollution (Kang at al., 2013). This has also been confirmed by the development of the ISO standard 12913 on soundscape, and by the launch of the European Soundscape Award, sponsored by the European Environment Agency (hereafter as EEA). In Germany, the growing interest for the soundscape approach has also been proved by the launch of the StadtKlang 2015 project in the frame of the Science Year 2015 City of the Future Program: StadtKlang is a digital and interactive platform which aims to collect sounds as representative of German places’ identity through public participation. Furthermore, the soundscape approach seems to be the most adequate one for planning quiet areas to the point that the European Environment Agency has encouraged scholars to experiment with mixed methodologies integrating the soundscape approach into the traditional acoustic ones (EEA, 2014).

Against this background, the Hush City app has been developed in the frame of the “Beyond the Noise: Open Source Soundscapes” project, which experiments with a novel mixed methodology to identify, assess and plan “everyday quiet areas” in cities, by implementing the soundscape approach, the citizen science paradigm and open source technology.

Whereas, traditional plans to protect quiet areas in agglomerations generally include huge parks and big green areas – identified by applying acoustical criteria (e.g. the Berlin Quiet Areas Plan), the research project’s thesis argues that different criteria should be applied by the municipalities in the identification of quiet areas in cities: such as people preferences and different scale. “Everyday quiet areas” shall be identified and protected: small, quiet spots embedded in our neighbourhoods, at a walking distance from the places people work and live. “Everyday quiet areas” shall be public and easily accessible to everyone (‘quietness as a commons’), whereas the positive impact of quiet spots in the immediate residential areas on the perception of noise and annoyance has been demonstrated in recent studies (Kang, Schulte-Fortkamp, 2016). Moreover, “everyday quiet areas” shall be identified and evaluated by the citizens, according to their preferences and life style (‘soundscape approach’), by the means of a proper participative process taking advantage of new technologies (‘bottom-up production of knowledge’).

In order to facilitate the citizens in collecting mixed and diverse data, the idea of using a digital tool seemed to be the most appropriate one, as it could be used by means of smartphones and carried out by citizens in their everyday life, independently by the researcher (citizen science paradigm). Accordingly, the Hush City app has been developed in order to empower local communities to play an active role in participative processes of sonic environment evaluation and planning.

The Hush City app offers users two possibilities:

1) to collect qualitative and quantitative data related to their favourite small, quiet spots in the neighbourhoods;




2) to identify and access small, quiet spots in the city, shared by other users.


Other facilities are also provided such as: the possibility to provide feedback on the app, to read more about the project, to review personal surveys and delete them at any time.


The Hush City app is conceived to positively impact on different levels:

1) improving human health and quality of life of citizens, city users and tourists;
2) implementing democratic participative processes, favouring the development of integrated urban planning processes.

Its advantages consist in the multiple facilities which are all embedded in a unique tool: the possibility to record sounds, calculate their noise levels, take pictures and provide user feedback by means of a predefined questionnaire.

Data collected are anonymously stored and are used only to compile worldwide maps of quietness of our cities.

Hush City App’s technology

Hush City app is a free, native mobile application, which runs on both iOS and Android operating systems: iOS 9.0 and higher (iPhones 5/5C/5S/SE/6/6Plus/7/7Plus) and Android 5 and higher (any Android based smartphone). A Titanium platform is used as a framework to record and store the data and a LAMP stack is used as a repository. Audio data are sampled at 44.100Hz, with a resolution of 16bit. The maximum length of the audio file is 30 seconds. Respective sound pressure levels are calculated as numeric scale values and they are A-weighted (i.e. 45 dB(A)). The A-weight is considered as the most appropriate for assessing environmental noise, due to similarity to human hearing (Thenuis et al. 2017). Leq (equivalent continuous sound level), Lmin (minum sound level) and Lmax (maximus sound level) are also calculated and displayed. NoiseTube’s app libraries have been consulted to select the most appropriate formulas for sound pressure level calculation (Maissoneuve et al. 2009). These formulas have been also double checked by a team of acoustic consultants involved in the project (see credits’ list below). Pictures are collected at a maximum resolution of 6MP and 24bit color. Sign-in feature: the users must verify their email before signing in and use the app as usual. If the users realize that they used wrong emails or made typos or mistakes after touching the Sign Up button, the app also allows them to change their email addresses.

Project Credits

The first version of the HUSH CITY app was developed in the framework of the project: “Beyond the Noise: Open Source Soundscapes” (2016-2018. The second version of the app was developed in the framework of the project: “Hush City Mobile Lab” (2018-2020).
Both projects have been developed by the principal investigator, Dr. Antonella Radicchi, at the Technical University of Berlin.
Project Supervisors: Prof. Dr. Dietrich Henckel (Technical University of Berlin), M.A. Jörg Kaptain (Berlin Senate, Senate Department for the Environment, Transport and Climate Protection).
Soundscape Advisor: Prof. Dr. Brigitte Schulte-Fortkamp (Technical University of Berlin).
Acoustic Advisors: Dipl. Ing. Michael Jäcker-Cüppers (ALD, Technical University of Berlin), Dipl. Ing. Manuel Frost (Berlin Senate, Senate Department for the Environment, Transport and Climate Protection), Dipl. Ing. Mattia Cobianchi (Bowers & Wilkins, UK).
Software Development: QUERTEX GmbH (GER) in cooperation with EdgeWorks Software, Ltd.


The HUSH CITY mobile app was derived from the concept of the HUSH EXPO app envisioned by Dr. Antonella Radicchi for the EXPO Milan 2015. The HUSH EXPO mobile app’s user interface was designed by Antonella Radicchi in collaboration with Roberto Lombardo.
The project: “Beyond the Noise: Open Source Soundscapes” has received funding from the IPODI-Marie Curie Fellowship – People Program (Marie Curie Actions) of the European Union’s Seventh Framework Program (FP7/2007-2013) under REA grant agreement no. 600209 (TU Berlin/IPODI).
The project: “Hush City Mobile Lab” has received funding from the HEAD-Genuit Foundation.

Privacy Policy – Terms and Conditions of Use

Your privacy is important to us. Please review this Privacy Policy and Terms and Conditions carefully.
Click here to download the document.

We believe in open data and we share and promote the open source approach; in this regard the Hush City’s code will be published under a CC license and shared with the community.