Chemical fingerprinting and toxicity of particulate matter from indoor sources

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Geochemical, mineralogical and morphological characterisation of road dust and associated health risks

Publication . Candeias, Carla; Vicente, Estela; Tomé, Mário; Rocha, Fernando; Ávila, Paula Freire; Alves, Célia

ABSTRACT: Road dust resuspension, especially the particulate matter fraction below 10 mu m (PM10), is one of the main air quality management challenges in Europe. Road dust samples were collected from representative streets (suburban and urban) of the city of Viana do Castelo, Portugal. PM10 emission factors (mg veh(-1) km(-1)) ranging from 49 (asphalt) to 330 (cobble stone) were estimated by means of the United Stated Environmental Protection Agency method. Two road dust fractions (<0.074 mm and from 0.0074 to 1 mm) were characterised for their geochemical, mineralogical and morphological properties. In urban streets, road dusts reveal the contribution from traffic emissions, with higher concentrations of, for example, Cu, Zn and Pb. In the suburban area, agriculture practices likely contributed to As concentrations of 180 mg kg(-1) in the finest road dust fraction. Samples are primarily composed of quartz, but also of muscovite, albite, kaolinite, microcline, Fe-enstatite, graphite and amorphous content. Particle morphology clearly shows the link with natural and traffic related materials, with well-formed minerals and irregular aggregates. The hazard quotient suggests a probability to induce non-carcinogenic adverse health effects in children by ingestion of Zr. Arsenic in the suburban street represents a human health risk of 1.58 x 10(-4).

2020Journal article

Open access

Passive monitoring of particulate matter and gaseous pollutants in Fogo Island, Cape Verde

Publication . Alves, Célia; Candeias, Carla; Nunes, Teresa; Tomé, Mário; Vicente, Estela; Ávila, Paula Freire; Rocha, Fernando

ABSTRACT: An air quality monitoring campaign by passive sampling techniques was carried out, for the first time, between November 2016 and January 2017 on the Cape Verdean island of Fogo, whose volcanic mountain rises up to 2829 m. Levels of SO2 and acid gases (HF, HCl, HNO3, H2SO4 and H3PO4) were, in most cases, below the detection limits. Alkylpentanes, hexane, cycloalkanes and toluene were the dominant volatile organic compounds. The m,p-xylene/ethylbenzene ratios revealed that air masses arriving at Cape Verde have been subjected to significant aging processes. High toluene/benzene ratios suggested extra sources of toluene in addition to vehicle emissions. Deposition rates of total settleable dust ranged from 23 to 155 mg/m(2)/day. On average, organic carbon accounted for 15.6% of the dust mass, whereas elemental carbon was generally undetected. Minerals comprised the dominant mass fraction. The dust levels were mostly affected by two main airflows: the westerlies and the Saharan Air Layer. These air masses contributed to the transport of mineral dust from desert regions, secondary inorganic constituents (SO42-, NO3- and NH4+) and tracers of biomass burning emissions, such as potassium. Sea salt represented 12% of the mass of settleable dust. Scanning electron microscope observations of several particles with different compositions, shapes and sizes revealed high silica mass fractions in all samples, as well as variable contents of carbonates, sulphates, aluminosilicates, Fe, Ti, F and NaCl, suggesting that, in addition to the already mentioned sources, dust is likely linked to industrial emissions in the northern and north-western coast of the African continent. Although some atmospheric constituents presented higher concentrations near the crater, the small fumarolic activity still present after cessation of the eruption in February 2015 has a limited impact on air quality, which is most affected by long range transport and some local sources at specific locations.

2018-12Journal article

Open access