Spatial Distribution of Air Pollution, Hotspots and Sources in an Urban-Industrial Area in the Lisbon Metropolitan Area, Portugal-A Biomonitoring Approach.

Leonor Abecasis,Zsofia Kertesz,Ana Rita Justino,Nuno Canha,Susana Marta Almeida,Carla A Gamelas,Isabel Dionísio

doi:10.3390/ijerph19031364

Abstract

This study aimed to understand the influence of industries (including steelworks, lime factories, and industry of metal waste management and treatment) on the air quality of the urban-industrial area of Seixal (Portugal), where the local population has often expressed concerns regarding the air quality. The adopted strategy was based on biomonitoring of air pollution using transplanted lichens distributed over a grid to cover the study area. Moreover, the study was conducted during the first period of national lockdown due to COVID-19, whereas local industries kept their normal working schedule. Using a set of different statistical analysis approaches (such as enrichment and contamination factors, Spearman correlations, and evaluation of spatial patterns) to the chemical content of the exposed transplanted lichens, it was possible to assess hotspots of air pollution and to identify five sources affecting the local air quality: (i) a soil source of natural origin (based on Al, Si, and Ti), (ii) a soil source of natural and anthropogenic origins (based on Fe and Mg), (iii) a source from the local industrial activity, namely steelworks (based on Co, Cr, Mn, Pb, and Zn); (iv) a source from the road traffic (based on Cr, Cu, and Zn), and (v) a source of biomass burning (based on Br and K). The impact of the industries located in the study area on the local air quality was identified (namely, the steelworks), confirming the concerns of the local population. This valuable information is essential to improve future planning and optimize the assessment of particulate matter levels by reference methods, which will allow a quantitative analysis of the issue, based on national and European legislation, and to define the quantitative contribution of pollution sources and to design target mitigation measures to improve local air quality.

Highlights

A–that is a steelwork that manufactures galvanized sheet metal and cold rolled sheet, with an installed capacity of 800,000 tons per year [27]; industry B–that is steelwork with an installed capacity of 215 tons per hour for the production of steel, where the main processes consist of an Electric Arc Furnace for steelmaking and hot rolling [28]; industry C–that it is a lime factory, which manufactures lime by calcination of limestone in a coke kiln [29]; and industry D that is a company focused on metal waste management and treatment
The methodology applied in this study allowed to involve the local population and to obtain a spatial distribution of the chemical elements absorbed by the lichens during a period where the activities in the area were mainly the industries, due to the COVID-19 national lockdown
A total of five different sources were identified as contributing to the local air quality: (i) a soil source of natural origin, (ii) a soil source of natural and anthropogenic origins, (iii) a source from the local industrial activity, namely steelworks; (iv) a source from the road traffic, and (v) a source of biomass burning

Summary

Introduction

Industrial emissions have an important contribution to particulate matter (PM) in urban-industrial areas [1,2]. To solve environmental problems in this type of areas it is crucial to understand and identify prevailing emission sources to promote targeted and successful mitigation measures. It is known that particulate matter may have adverse health effects, since PM may contain potentially toxic elements (PTEs) [3,4,5]. The determination of the chemical composition of PM aims to determine the sources of the PM sampled at receptor sites and to identify its potential health hazards

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Conclusion