Effectiveness of an air quality intervention: an accountability study in a highly polluted industrial town

Public interventions to reduce industrial emissions and improve air quality are particularly necessary in areas that suffer an environmental and health emergency. Taranto (Apulia region, Southern Italy) is one of the most industrialized cities in Southern Italy due to the massive presence of industrial sites, including a huge steel plant. The latter hosts a large open-air mineral deposit, whose dust strongly impacts the Tamburi neighborhood, downwind of the plant when the wind blows north-wester. In order to reduce the PM (particulate matter) and B(a)P (Benzo(a)pirene) concentrations in this neighborhood, the Apulia Region enacted a law restricting some industrial activities during certain meteorological situations, called wind days, characterized by strong north-westerly winds. Connected to the regional law, there was a Local Health Unit warning to the Tamburi population to ventilate indoor environments during the central hours of the day. The aim of this work is to assess the effectiveness and the appropriateness of the intervention implemented and to evaluate whether it effectively improved the air quality in the neighborhood close to the mineral deposit. Time-space statistical analysis of PM data measured by the fixed monitoring network before and after the intervention period was carried out. The analysis was performed for different meteorological conditions, different wind days characteristics (long/short), time periods, and other pollutants such as PAH (polycyclic aromatic hydrocarbon), which includes B(a)P for which measurements were not available. In the area closest to the industrial area, there was a reduction in the difference between the concentration of PM on wind days and those in other weather conditions. The reduction was more consistent on long, persistent wind days, when the difference in concentrations reduced from 13.3 to 3.9 ?g/m. However, the uncertainties regarding the wind days predictions suggest that the PM reduction may only partially be attributed to the regional law. Furthermore, the analysis of the PAH showed that there are weather conditions other than wind days that lead to a deterioration in the air quality in the neighborhood. Regarding the warning given by local health authorities to protect the population from dust injuries, the wind days daily PM profiles do not evidence a sharp reduction during the selected time slot, while other industrial pollutants clearly increase in the same time slot. Overall, results evidence the partiality of the intervention and call for a more comprehensive emissions plan to reduce their impact on air quality. In general, the study shows the need to periodically evaluate the effectiveness of any intervention and to take the consequent decisions to adapt them.