The city of L'Aquila, like many other Italian cities, is subject to air pollution coming from vehicles, domestic heating, and industrial plants. The earthquake that hit Aquila on 6th April 2009 has almost completely destroyed the road system, and only a few roads have been rebuilt and opened to the vehicles' traffic. The concentration of air pollutants like nitrogen oxides (NOx), sulfur oxides (SOx), particulate matter (PM1-PM10), carbon oxide (CO), etc, can overcome for several days beyond the level of attention. To protect the environment and the human's health, without restricting mobility and harming the local economy, the Municipality of L'Aquila, in cooperation with the University of Aquila, and in Public Private Partnership with Is Clean Air Italia Srl (ICA) and its parent company ISTECH, decided to install a cluster of 16 APA systems, capable to clean the air at the surface (ground) level, where is higher the concentration of atmospheric pollutants. APA technology is protected by international patents and has received important awards, both in Italy and abroad. In 2015 ISTECH obtained by the European Commission the contribution of SME - Phase 1 for the feasibility study and then, it was awarded by two Seals of Excellence under the Horizon 2020 framework Program, for boosting, the potential of small business in the area climate action, environment, resource efficiency and raw materials. APA abates pollutants through a very simple working mechanism, which reflects the natural cycle of rain. This multistage wet scrubber technology combines different physical-mechanical processes, operating as follows: the polluted air is drawn into a weak Venturi scrubber, which triggers the first abatement, producing a gas-water aerosol. This fluid is then introduced in a second process, in which a “scrubbing shower” precipitates the absorbed pollutants downwards, depositing them in a wastewater tank. A further wet deposition process (multiple quenching) ends the treatment and the purified air is returned to the environment. This process does not generate special wastes and has limited energy consumption, because APA has been designed with specific operating characteristics, in compliance with the basic principles of sustainability, from both an economic and an environmental point of view. APA, additionally, under the EU Directive 2008/1/CE is a “Best Available Technology”, that is a solution guaranteeing a high level of environmental protection, enabling the protection of workers’ and citizens’ health. Another important feature is the capability of being integrated in a simple and flexible way with other technologies, enabling the advanced Internet of Things (IoT) services and energy efficiency solutions. The results showed up to date a tangible reduction of atmospheric pollutants. In an observation of a limited period of only four weeks, for atmospheric particulate (PM10) the measured abatement efficacy was about 61%, while for nitrogen oxides it was about 58%. Confirming the initial hypothesis, it has been observed that the efficacy of the solution is strictly dependent on the position and distance among the APA systems (usually around 40-50 meters). The University of L'Aquila has developed a simulation tool to understand how the concentration of pollutants spreads into their territory, so to simulate the effectiveness of APA systems. Moreover, simulation models helped, before the deployment of the APA cluster, to choose the optimal position right away. The main beneficiaries of the project have been L'Aquila Municipality and their citizens. The first ones, indeed, take benefits from a solution with low running costs and IoT embedded services like hot-spot, Wi-Fi, video-surveillance and advertising signs, while the second ones benefit from clean air, have a free internet connection via hot-spot and the perception to be in a safer environment.
air pollution, clean air, particulate matter, smart city, pollutants