Differentiation of tomatoes based on isotopic, elemental and organic markers

Abstract. As part of the FORMES summer 2008 experiment, an Aerodyne compact time-of-flight aerosol mass spectrometer (cToF-AMS) was deployed at an urban background site in Marseille to investigate the sources and aging of organic aerosols (OA). France's second largest city and the largest port in the Mediterranean, Marseille, provides a locale that is influenced by significant urban industrialized emissions and an active photochemistry with very high ozone concentrations. Particle mass spectra were analyzed by positive matrix factorization (PMF2) and the results were in very good agreement with previous apportionments obtained using a chemical mass balance (CMB) approach coupled to organic markers and metals (El Haddad et al., 2011a). AMS/PMF2 was able to identify for the first time, to the best of our knowledge, the organic aerosol emitted by industrial processes. Even with significant industries in the region, industrial OA was estimated to contribute only ~ 5% of the total OA mass. Both source apportionment techniques suggest that oxygenated OA (OOA) constitutes the major fraction, contributing ~ 80% of OA mass. A novel approach combining AMS/PMF2 data with 14C measurements was applied to identify and quantify the fossil and non-fossil precursors of this fraction and to explicitly assess the related uncertainties. Results show with high statistical confidence that, despite extensive urban and industrial emissions, OOA is overwhelmingly non-fossil, formed via the oxidation of biogenic precursors, including monoterpenes. AMS/PMF2 results strongly suggest that the variability observed in the OOA chemical composition is mainly driven in our case by the aerosol photochemical age. This paper presents the impact of photochemistry on the increase of OOA oxygenation levels, formation of humic-like substances (HULIS) and the evolution of α-pinene SOA (secondary OA) components.

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Source apportionment of PM<sub>2.5</sub> in Cork Harbour, Ireland using a combination of single particle mass spectrometry and quantitative semi-continuous measurements

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-1035-2010 ◽

2010 ◽

Vol 10 (1) ◽

pp. 1035-1082 ◽

Cited By ~ 1

Author(s):

R. M. Healy ◽

S. Hellebust ◽

I. Kourtchev ◽

A. Allanic ◽

I. P. O'Connor ◽

...

Keyword(s):

Particle Number ◽

Particle Mass ◽

Anthropogenic Sources ◽

Carbonaceous Particles ◽

Continuous Measurements ◽

Organic Markers ◽

Solid Fuel Combustion ◽

Sulfate Particle ◽

Shipping Traffic ◽

A Site

Abstract. An aerosol time-of-flight mass spectrometer (ATOFMS) was co-located with a suite of semi-continuous instrumentation for the quantitative measurement of elemental carbon (EC), organic carbon (OC), sulfate, particle number and PM2.5 mass at a site in Cork Harbour, Ireland for three weeks in August 2008. Off-line analysis of polar organic markers was also performed for the same period. The data collected was used to identify and apportion local and regional sources of PM2.5. Over 550 000 ATOFMS particle mass spectra were generated and classified using the K-means algorithm. The vast majority of particles ionised by the ATOFMS were attributed to local sources, although one class of carbonaceous particles detected is attributed to North American or Canadian anthropogenic sources. The temporality of the ambient ATOFMS particle classes was subsequently used in conjunction with the semi-continuous measurements to apportion PM2.5 mass using positive matrix factorisation. Six factors were obtained, corresponding to vehicular traffic, marine, long-range transport, power generation, domestic solid fuel combustion and shipping traffic. The estimated contribution of each factor to the measured PM2.5 mass was 23%, 14%, 13%, 11%, 5% and 1.5%, respectively. Shipping was found to contribute 18% of the measured particle number (20–600 nm mobility diameter), and thus may have implications for human health considering the size and composition of ship exhaust particles.

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