gms | German Medical Science

Introduction: In recent years, several accountability studies have been conducted on the effectiveness of air quality regulations [1]. The present study focuses on the city of Taranto, an industrialized area in southern Italy, where one of the largest steel plants in Europe is situated. The health effects of air pollution were reported in several studies and the impact of the plant was investigated within a cohort study ordered by the Court of Taranto [2]. The aim of this study is to evaluate the impact of a regional law (October-2012), which, among others, imposes an obligation on the steel industry to reduce PM10 emissions from open mineral deposits. In particular, measures are required when strong winds are forecasted form northwesterly sectors (“wind days”) in order to prevent pollution in a neighborhood located close to the plant.

Materials and methods: We analyzed monthly PM10 data registered in the period 2009-2016 from two monitoring stations: one located in the neighborhood close (1.7 km) to the steel plant; the other one far away (13 km) from it. We used the latter as the control. We performed descriptive analyses and pre-/post intervention comparisons. Furthermore, in order to detect the impact of the regional intervention, we conducted an interrupted time series analysis [3]. We tested for autocorrelation using the Durbin-Watson test and adjusted regression standard errors for autocorrelation in the identified order [4].

Results: Steel production decreased in the observed period from a yearly mean of 7.1 million tons in 2009-2012 to yearly a mean of 5.7 in 2013-2016. After taking into account Saharan dust incursions, differences in PM10 concentrations during wind days and no-wind days reduced, decreasing from 9.2 in the period 2009-2012 to 1.4 μg/m3 in the period 2013-2016.

In the neighborhood close to the steel plant, the interrupted time series analysis showed a reduction in PM10 concentration levels following the intervention (-8.4μg/m3), but no difference in slope was observed between pre and post intervention.

Before the intervention, we did not observe any difference in slope in PM10 concentrations measured in the area close to the steel plant and at the monitoring station far away from it. We observed a difference (-2.1 μg/m3) in PM10 levels between the two series before (8.2 μg/m3) and after the intervention (6.1 μg/m3). However, the control series also showed a level change after the intervention (-2.2 μg/m3).

Discussion: We observed a strong reduction in the PM10 concentrations in the period after the intervention. However, the controlled interrupted time series analysis did not evidence any decrease in PM10 concentrations potentially associated with the intervention in the neighborhood close to the steel plant. Indeed, the reduction observed in PM10 levels in the neighborhood close to the industrial area might be associated with other factors, which also likely influenced the control time series.

An analysis of other air pollutants is required for a comprehensive evaluation of the intervention. Furthermore, research is needed in order to analyze the role of steel-production and meteorological variables in the concentration of PM10.

The authors declare that they have no competing interests.

The authors declare that an ethics committee vote is not required.