CONCLUSION

Nowadays, due to the constant increase of outdoor air pollution, the impact on the health of the people is becoming serious. Moreover, in the current vulnerable and crucial histori-cal period, when society is experiencing and dealing with the Covid-19 pandemic, the issue of people’s health is becoming even more important.

In 2019,the Global Burden of Disease Study estimated that outdoor air pollution is one of the main reasons for death in the world, with estimated 3.4 million deaths in 2017. These data highlight the danger to the health of people, taking into attention the international agencies such as the United Nations, that mentioned “good health and well-being” (SDG3) as a part of the 17 goals of the Sustainable Development declaration.

The concept of Outdoor Air Quality (OAQ) is a relevant topic, especially in the urban area, where population will continue to grow, expectingto reach 6.5 million people in 2050.

Therefore, it is essential to take in consideration the health and wellbeing of the people.

The main goal of my thesis was to study the effects of air pollution on people’s health and to investigate how the diseases affect the society and the economy. In particular, the developed analysis allowed to provide scientific outcomes which could be suitable for sup-porting the urban planning decision-making process.

Studying the main sources of air pollution, 30% of emissions are caused by the heating systems in Europe. Based on this information, the thesis had set two main objectives, fo-cusing on the residential sector of the city of Torino. Firstly, using the reference building approach, a simplification of the residential building stock of Torino was done, in order to evaluate its current emissions, not only in terms of CO2 emissions, but also considering the local impact due to air pollutants (i.e. PM, NOx, SOx, CO, etc.). Based on the current state, different retrofit scenarios were identified, in order to evaluate those able to guarantee the highest emissions reductions. Two families of scenarios were developed, the first im-proving only the heating systems, and the second coupling also envelope interventions with heating system retrofit. Four scenarios were then compared in terms of total emis-sions and net avoided emisemis-sions (with respect to the current state). Moreover, the thesis aimed also to quantify the impact of health diseases caused by air pollution exposure on

economy and society, and thus to evaluate the benefits on social costs guaranteed by the developed scenarios. The methodology used to monetize the air pollution health ef-fects was defined after a preliminary literature review on the topic. In particular, thanks to an epidemiological bibliographic study, the social cost assessment was developed only considering particulate matter (PM) emissions, which emerged to be the most dangerous pollutant, causing respiratory and cardiovascular diseases.

The thesis focused on the method of Cost of Illness (C.O.I.). In particular, the Human Capi-tal Approach (H.C.A.) was used to calculate direct costs, while the Willingness to Pay (WTP) method was deployed to estimate the intangible costs.

Based on the retrofit scenario analyses, the results brought out that the use of biomass source produces a negative effect, showing an increase of CO, NMVOC, and PM emissions with respect to the current state. Therefore, when considering a system retrofit scenario without permitting a shift towards biomass systems, a PM10 emission reduction of almost 30% can be achieved. However, the complete retrofit scenarios (built coupling envelope and system interventions) allowed to increase the emissions reduction, obtaining a 40%

and 45% PM10 reductions when considering the standard and advanced complete ret-rofit scenarios, respectively. Moreover, the four scenarios were built assuming different renovation rates, some similar to the typical Italian annual renovation rates (0.8%, 1.2%

and 2.5%), and some assumed to simulate stronger retrofit uptakes (25%, 50%, 75% and 100%). Clearly, the highest emissions reductions are associated to the highest renovation rates. However, it is important to clarify that only 75% of the building stock floor area was assumed to be potentially renovated (excluding buildings built before 1945 and built after 2005).

Focusing on the social effects of air pollution, it appears that PM10 causes approximate-ly 2900 deaths cases per year and reduces life expectancy by 3 years. Appapproximate-lying the COI method, it was possible to associate to PM10 emissions an annual social cost of more than 1100 € per person. Intangible costs contribute to two thirds of this social cost, while direct costs only account for around 500 €/person per year.

A parametric index expressed in €/tPM10 was used in order to estimate the social costs and the associated benefits guaranteed by the developed retrofit scenarios. Almost all scenarios, with the diverse renovation rates assumptions, allowed to guarantee some eco-nomic benefits, increasing with the renovation rate. The highest values are achieved for the standard and advanced complete retrofit scenarios, for the 100% annual renovation

147 rates, equal to almost 450 €/person per year and 550 €/person per year respectively. The

sole exception is represented by the system retrofit scenario with biomass (for all the as-sumed renovation rates), which induced negative effects on the overall social cost.

The thesis and the obtained results are interesting, since they clearly show the effect that residential heating has on outdoor air quality. Moreover, it is clear that the highest ben-efits are associated with the highest renovation rates, showing how urban policy should stress on this topic.

The work opens the way to future work on this field. In particular, on the economic side, it would be interesting to estimate the local (or national) WTP, by submitting surveys to the population of Torino. On the energy side, the thesis concentrated on traditional technolo-gies (i.e. condensing gas boiler, biomass boiler, electric heat pump). However, it would be interesting to consider the same technologies with higher efficiency, or to explore other technologies (e.g. district heating), as well as renewable energy sources, in order to evalu-ate how their adoption could strongly increase the urban emissions reductions.

Finally, the thesis was developed considering a single year assessment. In the future, it would be interesting to expand the research to a long-term study perspective, trying to explore the evolution of the urban residential sector up to 2050, considering the future technological maturity, in order to estimate the potential environmental and social bene-fits associated to the residential energy transition.

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