Abstract
In this work, time-series analyses of the chemical composition and source contributions of PM2.5 from an urban background station in Barcelona (BCN) and a rural background station in Montseny (MSY) in northeastern Spain from 2009 to 2018 were investigated and compared. A multisite positive matrix factorization analysis was used to compare the source contributions between the two stations, while the trends for both the chemical species and source contributions were studied using the Theil–Sen trend estimator. Between 2009 and 2018, both stations showed a statistically significant decrease in PM2.5 concentrations, which was driven by the downward trends of levels of chemical species and anthropogenic source contributions, mainly from heavy oil combustion, mixed combustion, industry, and secondary sulfate. These source contributions showed a continuous decrease over the study period, signifying the continuing success of mitigation strategies, although the trends of heavy oil combustion and secondary sulfate have flattened since 2016. Secondary nitrate also followed a significant decreasing trend in BCN, while secondary organic aerosols (SOA) very slightly decreased in MSY. The observed decreasing trends, in combination with the absence of a trend for the organic aerosols (OA) at both stations, resulted in an increase in the relative proportion of OA in PM2.5 by 12% in BCN and 9% in MSY, mostly from SOA, which increased by 7% in BCN and 4% in MSY. Thus, at the end of the study period, OA accounted for 40% and 50% of the annual mean PM2.5 at BCN and MSY, respectively. This might have relevant implications for air quality policies aiming at abating PM2.5 in the study region and for possible changes in toxicity of PM2.5 due to marked changes in composition and source apportionment.
Highlights
Air pollution is a major environmental issue around the world (IHME, 2020, 2018; World Health Organization (WHO), 2016)
Currently no clear hierarchy in toxicity of particulate matter (PM) components has been found due to their complex compositions and interactions with other pollutants, studies have indicated that organic carbon (OC), elemental carbon (EC), and metals such as Ni and V appear to have a larger impact on the overall toxicity of PM2.5, while there is less evidence to connect secondary inorganic aerosols (SIA) with health effects in laboratory studies (Hime et al, 2018; Kelly and Fussell, 2012; Park et al, 2018) and epidemiology studies
We focus on Barcelona (BCN) (NE Spain; 4.6 million inhabitants in the metropolitan area), which is a seaside city with numerous anthropogenic emission sources of air pollutants, such as road traffic, industrial plants, and shipping (Amato et al, 2016; Pandolfi et al, 2020), and on the Montseny (MSY) Massif northeast of Barcelona (Cusack et al, 2012; Pandolfi et al, 2016)
Summary
Air pollution is a major environmental issue around the world (IHME, 2020, 2018; WHO, 2016). The European Aerosols Monitoring and Evaluation Program (EMEP) evaluated air quality trends for 1990–2012 in Europe, finding a decrease of approximately 30% for both PM10 and PM2.5 between 2000 and 2012 and reductions of 60% to 90% and 30% to 40% for sulfate (SO42−)- and nitrate (NO3−)-bearing pollutants in PM10, respectively (EMEP/CCC, 2016; ETC/ACM, 2016) In spite of this decrease in the levels of PM and gaseous pollutants, EEA (2020) reported that in 2018, 48% and 74% of the EU-28 urban population were exposed to PM10 and PM2.5 concentrations that exceeded the WHO Air Quality Guidelines (AQG) (WHO, 2006) of 20 μgm−3 for annual average PM10 and 10 μgm−3 for annual average PM2.5, respectively. WHO (2013) stated that SIA species may have health effects associated with them
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
