High Contribution of Biomass Combustion to PM2.5 in the City Centre of Naples (Italy)

Abstract

A better knowledge of the local and regional sources of the atmospheric particulate matter provides policy makers with the proper awareness when acting to improve air quality, in order to protect public health. A source apportionment study of the carbonaceous aerosol in Naples (Italy) is presented here, in order to improve this understanding in a vulnerable urban area. The aim of this study is quantifying directly fossil and non-fossil contributions to carbonaceous aerosol, by means of radiocarbon measurements. This is the first time that such an approach is implemented in this area. Fine particles with diameter ≤ 2.5 µm (PM2.5) were collected daily on top of a building in the city center, from November 2016 until January 2017. The carbonaceous aerosol was separated into organic carbon (OC) and elemental carbon (EC), by a two-step thermal desorption method. Subsequent radiocarbon analysis enabled the partitioning of the major sources of carbonaceous aerosol into fossil and non-fossil ones by applying radiocarbon isotopic mass balance. The PM2.5 concentration was on average 29 ± 3 µg⁄m3 (mean ± standard error; n = 18), with a maximum of 68.6 ± 0.7 µg⁄m3 on a day when air masses back-trajectories suggest a local origin and stagnant airflow conditions in the region. The carbonaceous component accounts for roughly half of the PM2.5 mass. Fossil fuel emissions are a minor source of OC (23%), but the dominant source of EC (66%), which is directly emitted during combustion processes. However, overall only 30% of the total carbon is of fossil origin, accounting for 14% of PM2.5 mass. Surprisingly, a comparable contribution is due to primary biomass burning carbon, which accounts in total for 15% of PM2.5 mass. Traffic pollution, the main cause of fossil fuel emissions in urban areas, is a significant, but not the predominant source of carbonaceous particle concentration. These findings support the conclusion of a predominant contribution from non-fossil sources to the carbon in airborne particulate matter, which policy makers should take into account when planning mitigation strategies to improve urban air quality.

Particulate Matter Ionic and Elemental Composition during the Winter Season: A Comparative Study among Rural, Urban and Remote Sites in Southern Italy

“…In particular, the enrichment in Ca 2+ could be attributed to dust from soil resuspension in urban and suburban environments (no transport of desert dust was observed during this field campaign), while K + enrichment could testify to the significant use of biomass burning for heating systems; this observation was particularly true at the NAP site, due to the accumulation of K + in the smaller particles (PM 2.5 fraction). The higher contribution from anthropogenic sources was also supported by the measured organic/elemental carbon (OC/EC) content at the same site [19,65]. In that work, the authors analyzed the carbon content in PM from the same monitoring campaign and showed that the highest levels were achieved in Naples (12.8 ± 5.1 and 11.8 ± 4.6 µg/m 3 for organic carbon in PM 10 and PM 2.5 ; 2.3 ± 1.1 and 1.8 ± 0.5 µg/m 3 for elemental carbon in PM 10 and PM 2.5 ).…”

“…It is within a restricted traffic area and near to the marina, but not far from heavily trafficked roads. It is influenced by multiple sources, e.g., vehicular traffic, port emissions and biomass combustion from the numerous pizza restaurants nearby, combined with widespread pollution conditions [17][18][19][20][21][22]. Lecce (LEC, 40.3°N, 18.1°E) is an urban background site located on the roof of CNR-ISAC (Istituto di Scienze dell'Atmosfera e del Clima, Italian National Research Council) at 12 m above ground level and about 4 km south-west of Lecce town center.…”

Chemical characterisation of PM10 from ship emissions: a study on samples from hydrofoil exhaust stacks

“…In addition, the harbours are close to a densely populated urban area (about 1,000,000 inhabitants), which is characterized by the presence of many other pollutant emission sources: vehicular traffic, domestic and commercial combustions and air traffic due to the nearby Capodichino Airport. These sources determine the air quality in the urban area, which is characterized by severe PM pollution (Agrillo et al 2013;Chianese et al 2019;Dinoi et al 2017;Riccio et al 2014;Sirignano et al 2019).…”

“…Currently available data about EC and OC for the urban area of Naples were reported in studies conducted by Dinoi et al (2017) and by Sirignano et al (2019). In these studies, it was hypothesized that the sampling site, located in the centre of the urban area of Naples (close to marina, at 53 m a.s.l.…”

Tropical Air Chemistry in Lagos, Nigeria

“…In contrast, biomass combustion is highly variable, depending on the biomass resource and the burning conditions. The ratio can vary from ~1 to >5, e.g., [51,52]. A ratio of <~1.9 could be interpreted as the primary aerosol associated with motor vehicle and biomass burning emissions alone.…”