The Noise Low Emission Zones Abacus has been realized, as an outcome of preliminary actions. It was carried out in the first months of the project and it contains detailed information about the actual state of the art: the most recent monitoring system of noise and air quality, health indicators, actions and its effects of the noise, air quality and health.
The ‘top-down’ actions have focused on ‘Viale Libertà’. Particularly, in the first months of the project, the Limited Traffic Zone, so-called ZTL, was introduced for the limitation of accesses to the avenue for heavy vehicles - max 3.5 tons initially from December 2018 to May 2019 and max 7.5 tons from May 2019 to August 2020-. An alternative pathway has been foreseen for excluded means of transports outside the city centre.
1) On large scale, the low-noise asphalt represents the main instrument for the decrease of the traffic noise through interventions at the noise source and nowadays several technologies are available and based on composition, used materials and field of use.
For the laying of the asphalt, the typology “Dense graded at optimized weaving” has been chosen, which guarantees results of 3-4 dB(A) in term of acoustic abatement and an efficiency period of about five years from the laying. In Figure 1 the section of Viale Libertà interested by the new asphalt laying is shown. In this road the work has foreseen the removal of the old road surface and the laying of 4 cm of link-layer (BINDER) and 4 cm of DENSE GRADED asphalt on the top.
The laying works for the new low-noise asphalt started on Monday 17th September 2018 and finished on Saturday 22nd.
Figure 1 – Detail design of interventions in Viale Libertà
Figure 2 – New road pavement on Viale Libertà (photo taken by LIFE MONZA staff)
2) Regarding the limitations of the traffic in the pilot area of Libertà district, the first one was already ongoing since 21st January 2019. For the first six months (January-July 2019) the access to vehicles heavier than 3,5 ton was forbidden, whereas in the following three months (July- October 2019) the limitation regarded only vehicles heavier than 7,5 ton.
Among the activities carried out in the LIFE MONZA project, the noise monitoring has been planned in the ante and post-operam scenario, by using both the class I instrumentation and a new low-cost monitoring sensor network developed into the project, in order to study the efficiency of interventions planned to reduce the traffic noise in this area. Moreover, some counter-traffic units were put in place to monitor road traffic flows.
About bottom-up actions, for encouraging the involvement of citizens in the project phase, a “Pedibus” service has been provided in school years 2018/2019 and 2019/2020 for all pupils of the primary school located in Viale Libertà.
Pedibus foresees the following actions:
- Survey of scholastic mobility through a questionnaire to school students;
- Educational meeting at school with students and teachers;
- A meeting for the awareness, coordination and monitoring of the mid-term assessment on the pedibus.
A meeting for the Libertà City Centre was carried out in November 2018 together with local associations and citizens to create a group of voluntaries as helpers and supporters of the Pedibus (Figure 3).
Figure 3 – Meeting of the steering committee of Libertà district (photo taken by LIFE MONZA staff)
It was decided to design a free application for mobile phones that can manage some Pedibus services and another service called “on foot or by bike in Libertà”, which measures the movements people do while walking or cycling within the Libertà district, with incentives for more virtuous citizens.
Moreover, acoustics data are available within the App and they will have periodical assessments thanks to the HARMONICA index. Accessory services and additional tools, suggested by citizens, will be available in this App.
Figure 4 – Sensors of the network of low-cost acoustic monitoring (photo taken by LIFE MONZA staff)
Figure 5 – Smart sensor of the network of low-cost acoustic monitoring (photo taken by LIFE MONZA staff)
In Figure 6, the noise monitoring positions are shown, together with the positions of counter-traffic control units and low-cost sensors (Smart Noise Monitoring System “SNMS”) to evaluate noise pollution both in ante and post-operam scenario.
Figure 6. Different kind of measuring systems and related positions for monitoring noise in the pilot area.
With reference to one of the sensors (HC101) placed along Libertà street (Figure 6), , the results of the two interventions achieved in the Libertà district (laying of the new low-noise pavement and traffic limitation for heavy vehicles) will be illustrated.
This sensor has been placed in correspondence of the façade of the Civic Centre and the results take account of the façade’s reflection.
At the end of the validation of smart monitoring system of noise a new specific procedure based on periodical comparison of measurement chain in class I has been elaborated. Moreover, weekly phonometric monitoring with instruments in class I has been carried out. Following the audit, the new system shows good reliability (Figure 7).
Figure 7 – Graphic of comparison on noise levels of the phonometric chain in class I and smart sensor
In particular, Figure 8 shows the contribution of the new laying of low-noise asphalt in Viale Libertà: on the left of the graph the A-weighted continuous equivalent sound pressure level, “LAeq”, is referred to one week before the intervention, in the middle of the diagram the sound pressure level recorded during the laying is presented and on the right of the graph results are recorded for eighteen days after one month from the laying. This one-month-gap is considered as a necessary period for the settling of the paving. Focusing on these first elaboration data, it is possible to see a visible noise reduction due to the laying of the new low-noise road surface.
Figure 8. Noise levels recorded by the sensor HC101 before, during and after the laying of the new road surface
Furthermore, referring to the same sensor HC101, in Figure 9 the trend of noise levels in the week before and after the traffic limitation for the vehicles heavier than 3,5 ton (performed from 21st January 2019), has been reported. However, in this case, the effect of this action is not visible on the time history of sound pressure level recorded.
Figure 9.Noise levels recorded by the sensor HC101 before and after the stop of heavy vehicles
Referring to the long-term monitoring, performed by using the class I instrumentation, the comparison between the monitoring activity carried out in November 2017 and in January 2019 has been made. The position identified as P01 (Figure 6) and located on the roof of the Civic Centre facing the Libertà street has been taken as reference.
Figure 10. Comparison of sound pressure levels recorded in ante and post operam in the position of the Civic Centre
Referring to the traffic flow data, based on the road-traffic counting, performed in ante and post operam scenarios, it is possible to affirm that, in the “Day” timeframe, there is a very good alignment between data of the ante and post-operam scenarios. Also in “Evening” and “Night” the deviations of the traffic flows between ante and post-operam scenarios are small (lower than 10%). Finally, referring to heavy vehicles, in all the periods a reduction of the 30%, between the configuration ante and post-operam, is appreciable.
This result confirms that the attenuation observed in the graphic in figure 6, in term of sound pressure level, is essentially due to the interventions realised.
In particular, a very good attenuation is obtained in “Evening” and “Night” timeframes probably due to the presence, in these periods, of traffic flow moving in a fluid mode able to increase the performance of the low noise paving intervention.
Table 1. Analysis of the results obtained for the acoustic descriptor Lday, Levening and Lnight by the low-cost sensors and class I systems
As shown in the following table 1, the results of the noise monitoring carried out in January 2019 highlight the same and constant difference of about 3 dB, between the sound pressure levels recorded by low-cost sensor and class I systems in all periods analysed (Day, Evening and Night). This difference is caused by the different position of the microphones. This stability of results seems to make the low-cost sensors usable for noise monitoring in the place of class I instrumentation.
Instead, in the measurements of November 2017 only during the “Night” the difference cited above is equal to 3 dB, while in “Day” and “Evening” there is a bigger deviation probably due to the activities carried out nearby of the entrance of Civic Centre and therefore close to the sensor. In the light of these considerations, the results in “Day” and “Evening” haven’t been used for the comparison of the results.
Table 2. Comparison of the results obtained for the acoustic descriptor Lday, Levening and Lnight between the two measurement systems used in the monitoring of the ante and post-operam
After comparing the results obtained in the monitoring of the ante and post-operam scenarios, we can conclude with the following considerations:
- in the “Evening” and “Night” periods, when there are passages of only light vehicles and the traffic is fluid, there is a great result because the intervention of low-noise laying mainly works on the rolling noise;
- in the “Day” period, when there isn’t fluid traffic with the presence of situations of “stop and go” due to a traffic light, the efficacy of the laying of road surface is lesser precisely because this kind of intervention principally works on the rolling noise.
As a conclusion of the performed analysis, the interventions realised in Viale Libertà of the city of Monza (new low-noise pavement’s laying and the limitation of the heavy vehicles passage for the means larger than 3,5 ton) provide very good results in terms of abatement of the traffic noise in the pilot area of LIFE Monza project.
In particular, in terms of noise monitoring with class I instrumentation, the reduction in terms of sound pressure levels measured during the “Day”, between ante and post-operam, is equal to 2 dB. In the “Evening” and “Night” this reduction is higher, up to 6 dB during the night.
Moreover, repeating the same analysis based on the low-cost sensor, it is possible to observe an excellent alignment between the noise levels’ difference obtained with the two different measurement systems.
Table 3 – Attenuations of weekly sound pressure level during night ante and post-operam using the two measurement systems.
Questionnaire
A questionnaire has been formulated with questions taken from the standard questionnaire WHOQOL-Bref and questions concerning annoyance have been added. This questionnaire has been distributed to citizens from school students of Libertà district as part of the alternating work-school project. So far we have collected about 200 questionnaires.
To study the effects of activities carried out in the project (infrastructural, organizing and awareness actions) on the local social system, we had decided to use research methods aimed at detecting, analysing and evaluating the opinions, perceptions and attitudes of the concerned population regarding a number of aspects related to the liveability of the neighbourhood and the conditions of environmental and social well-being.
Therefore, a diachronic spot-check investigation has been designed and started. It foresees two revelations: the first (pre-test) has already been realised to define the ex-ante situation, the second (post-test) aims to record the conditions after the actuation of infrastructural actions and other measurements foreseen by project so that it can evaluate the changes occurred.
Data collection has been carried out through the administration of semi-structured questionnaires to distinctly selected samples for the two time phases, which are representative of the citizens living in the "Libertà" district. The pre and post-test questionnaires have in common almost all questions to aim at a good comparison between ex-ante and ex-post situations and are divided into thematic areas concerning personal data, home, the perception of life quality in the district, air and noise pollution, health, mobility and knowledge of the LIFE MONZA project and its possible impacts on the local system.
Pre-test questionnaires have been sent by postal service, after filling the blanks autonomously, the interviewees have delivered them to the collection centre set up for this purpose. A second option was an online compilation, with direct access for each interviewee at questionnaire.
Regarding the sample, a random sampling stratified strategy has been carried out by typologies, age classes and spatial distribution into Libertà district.
The same procedure will be replicated in 2019, during the second recording (post-test). According to the questionnaires’ outcomes (pre-test had involved overall 177 subjects, about 31% of the foreseen cases by sampling), the variety of the answers allows all comparisons and analysis in pre-test and a correlation between pre and post-test.
Indeed, all citizens considered in the samples have been involved and a certain proportionality between the different types of population has been respected, except for the citizens that live within 30 meters from Viale Libertà who responded more consistently (97% of original sample, while for those over 30 meters the coverage stops at 24% ).
Further results related to the definition of a new global environmental indicator, that takes into account noise parameters, air quality, health and social and economic aspects, has been evaluated and it will also highlight the overall benefits of the project.
The comparison between the several monitoring data in the pilot area, acquired in ante and post-operam phases will allow the evaluation of the real impacts caused by the introduction of the Noise LEZ and the definition of the obtained benefits.
Communicative and dissemination initiatives
During the project several dissemination actions were planned such as participating of national or international scientific conferences, workshops, study day, etc...(Figures 7,8).
Figure 7 - Noise & the City Conference- Florence 2018, Dr. Raffaella Bellomini (Vie en.ro.se Ingegneria) (photo taken by LIFE MONZA staff)
Figure 8 - Noise & the City Conference- Florence 2018. Dr. Carlo Nicola Casati (Municipality of Monza) (photo made by LIFE MONZA staff)
According to the public we wanted to inform and involve in the project, the activities had been distinguished in awareness and information activities to increase the knowledge of this issue and technical activities addressing to the scientific community.
Figure 9 - Prizegiving of contests of ideas at the Mapelli Institute held in 225/05/2018 in Monza (photo taken by LIFE MONZA staff).
Many training/information meetings have been organised in the schools of Libertà district and contests of ideas instituted for the creation of the project’s logo and related slogan (Figure 9).
In the meeting with the students of the different schools, we have organized different contents according to the specific audience and the project has been explained with topics related to physics and sound perception.
The project also included the participation in the International Noise Awareness Day annually organised by the European Acoustics Association and the Italian Acoustics Association. There was significant participation in the meetings organised by the Eurocities network, which is dedicated to noise pollution, bringing together the main European cities with the presentation and discussion of the project’s contents.
To celebrate the 25° anniversary of the establishment of the LIFE project, a workshop was organised allowing to compare the results of the Italian project in the environmental noise field, co-funded by the program.
Noise & the City conference had been organised in Florence and it had enhanced the number of people involved in the discussion, because it allowed explaining this project at local/national institutions with the presence of European experts as well. Networking activity has been started with LIFE DYNAMAP and LIFE NEREIDE projects particularly regarding the sharing of methodology and techniques about low-cost monitoring system of noise and low-noise flooring types.