The Covid-19, an unexpected "tool" to assess the chances of reaching the WHO recommended noise limits in medium-sized cities

Noise is one of the main health problems in cities. The World Health Organization (WHO) has recommended a limit for both the day-evening-night noise indicator (Lden) and the night-time noise indicator (Ln). Values above these limits are associated with adverse health effects. Given that the main source of noise is road traffic, the question that arises is whether these limits can be achieved in a reasonable period without substantially altering the economic or social activities that usually take place in the city. The SARS-CoV-2 pandemic has prompted governments in many countries to take extreme measures to reduce the spread of the virus. Typically, the most widespread measure has been to reduce citizens' mobility and gatherings. It is in this context of extreme disruption of the daily activity of a city where we can analyse whether the limits for the noise indices proposed by the WHO have been reached and, therefore, we have achieved quiet and healthy cities in compliance with these limits. In this work, we analyse the sound situation in an urban environment before and after the appearance of SARS-CoV-2 and we analyse whether the objectives of the WHO have been reached.