A sustainable acoustic customization of open porous materials using recycled plastics.

Foams are commonly used as sound absorbers and thermal insulators for many industrial and construction applications. The insulating materials market is currently dominated by inorganic fibres like glass and mineral wool, as well as plastic foams. However, worldwide plastics consumption produces huge amounts of waste, generating concerns about soil, air and especially seawater pollution. Hence, new methods for recycling marine microplastic litter according to cleaner production criteria are being sought. This paper presents a novel, sustainable and eco-friendly foamy material made of microplastic waste, namely polyethylene terephthalate (PET) and polystyrene (PS), incorporated into a bio-based matrix. Samples with different compositions were prepared and then characterized for sound absorption properties. Evidence is presented of very good acoustic performances and of how the acoustic characteristics of the end product can be customized using different microplastic content and type. This allows envisioning many industrial and civil applications for this novel open-cell material.

Indoor and outdoor noise changes due to the COVID-19 lockdown and their effects on individuals' expectations and preferences.

The COVID-19 pandemic significantly modified our urban territories. One of the most strongly affected parameters was outdoor noise, caused by traffic and human activity in general, all of which were forced to stop during the spring of 2020. This caused an indubitable noise reduction both inside and outside the home. This study investigates how people reacted to this new unexpected, unwanted and unpredictable situation. Using field measurements, it was possible to demonstrate how the outdoor sound pressure level clearly decreased. Furthermore, by means of an international survey, it was discovered that people had positive reaction to the lower noise level. This preference was generally not related to home typology or location in the city, but rather to a generalized wish to live in a quieter urban environment.

How much COVID-19 face protections influence speech intelligibility in classrooms?

The ongoing pandemic caused by the COVID-19 virus is challenging many aspects of daily life. Several personal protective devices have become essential in our lives. Face protections are mostly used in order to stop the air aerosol coming out of our mouths. Nevertheless, this fact may also have a negative effect on speech transmission both in outdoor and indoor spaces. After a severe lockdown, classes have now started again. The adoption of face protection by teachers is either recommended or mandatory even though this is affecting speech intelligibility and thus students' comprehension. This study aims to understand how protections may affect the speech transmission in classrooms and how this could be influenced by the several typologies of face protections. An experimental campaign was conducted in a classroom in two different reverberant conditions, measuring and comparing the variation in speech transmission and sound pressure level at different receiver positions. Furthermore, a microphone array was used to investigate the distribution of the indoor sound field, depending on the sound source. Results clearly show how different types of personal protection equipment do affect speech transmission and sound pressure level especially at mid-high frequency and that the source emission lobes vary when wearing certain types of personal devices.

Assessment of health-care waste management in a humanitarian crisis: A case study of the Gaza Strip.

Health-care waste management requires technical, financial and human resources, and it is a challenge for low- and middle income countries, while it is often neglected in protracted crisis or emergency situations. Indeed, when health, safety, security or wellbeing of a community is threatened, solid waste management usually receives limited attention. Using the Gaza Strip as the case study region, this manuscript reports on health-care waste management within the context of a humanitarian crisis. The study employed a range of methods including content analyses of policies and legislation, audits of waste arisings, field visits, stakeholder interviews and evaluation of treatment systems. The study estimated a production from clinics and hospitals of 683kg/day of hazardous waste in the Gaza Strip, while the total health-care waste production was 3357 kg/day. A number of challenges was identified including lack of clear definitions and regulations, limited accurate data on which to base decisions and strategies and poor coordination amongst key stakeholders. Hazardous and non-hazardous waste was partially segregated and treatment facilities hardly used, and 75% of the hazardous waste was left untreated. Recommendations for mitigating these challenges posed to patients, staff and the community in general are suggested. The outputs are particularly useful to support decision makers, and re-organize the system according to reliable data and sound assumptions. The methodology can be replicated in other humanitarian settings, also to other waste flows, and other sectors of environmental sanitation.

How to assess solid waste management in armed conflicts? A new methodology applied to the Gaza Strip, Palestine.

We have developed a new methodology for assessing solid waste management in a situation of armed conflict. This methodology is composed of six phases with specific activities, and suggested methods and tools. The collection, haulage, and disposal of waste in low- and middle-income countries is so complicated and expensive task for municipalities, owing to several challenges involved, that some waste is left in illegal dumps. Armed conflicts bring further constraints, such as instability, the sudden increase in violence, and difficulty in supplying equipment and spare parts: planning is very difficult and several projects aimed at improving the situation have failed. The methodology was validated in the Gaza Strip, where the geopolitical situation heavily affects natural resources. We collected information in a holistic way, crosschecked, and discussed it with local experts, practitioners, and authorities. We estimated that in 2011 only 1300 tonne day(-1) were transported to the three disposal sites, out of a production exceeding 1700. Recycling was very limited, while the composting capacity was 3.5 tonnes day(-1), but increasing. We carefully assessed system elements and their interaction. We identified the challenges, and developed possible solutions to increase system effectiveness and robustness. The case study demonstrated that our methodology is flexible and adaptable to the context, thus it could be applied in other areas to improve the humanitarian response in similar situations.

Using social network and stakeholder analysis to help evaluate infectious waste management: a step towards a holistic assessment.

Assessing the strengths and weaknesses of a solid waste management scheme requires an accurate analysis and integration of several determining features. In addition to the technical aspects, any such system shows a complex interaction of actors with varying stakes, decision-making power and influence, as well as a favourable or disabling environment. When capitalizing on the knowledge and experience from a specific case, it is also crucial that experts do not "forget" or underestimate the importance of such social determinants and that they are familiar with the methods and tools to assess them. Social network analysis (SNA) and stakeholder analysis (SA) methods can be successfully applied to better understand actors' role and actions, analyse driving forces and existing coordination among stakeholders, as well as identify bottlenecks in communication which affect daily operations or strategic planning for the future way forward. SNA and SA, appropriately adjusted for a certain system, can provide a useful integration to methods by assessing other aspects to ensure a comprehensive picture of the situation. This paper describes how to integrate SNA and SA in order to survey a solid waste management system. This paper presents the results of an analysis of On-Nuch infectious waste incinerator in Bangkok, Thailand. Stakeholders were interviewed and asked to prioritize characteristics and relationships which they consider particularly important for system development and success of the scheme. In such a way, a large quantity of information about organization, communication between stakeholders and their perception about operation, environmental and health impact, and potential alternatives for the system was collected in a systematic way. The survey results suggest that stakeholders are generally satisfied with the system operation, though communication should be improved. Moreover, stakeholders should be strategically more involved in system development planning, according to their characteristics, to prevent negative reactions.