Identification and quantification of organic aerosol from cooking and other sources in Barcelona using aerosol mass spectrometer data

Abstract

Abstract. PM1 (particulate matter with an aerodynamic diameter <1 μm) non-refractory components and black carbon were measured continuously together with additional air quality and atmospheric parameters at an urban background site in Barcelona, Spain, during March 2009 (campaign DAURE, Determination of the sources of atmospheric Aerosols in Urban and Rural Environments in the western Mediterranean). Positive matrix factorization (PMF) was conducted on the organic aerosol (OA) data matrix measured by an aerosol mass spectrometer, on both unit mass (UMR) and high resolution (HR) data. Five factors or sources could be identified: LV-OOA (low-volatility oxygenated OA), related to regional, aged secondary OA; SV-OOA (semi-volatile oxygenated OA), a fresher oxygenated OA; HOA (hydrocarbon-like OA, related to traffic emissions); BBOA (biomass burning OA) from domestic heating or agricultural biomass burning activities; and COA (cooking OA). LV-OOA contributed 28% to OA, SV-OOA 27%, COA 17%, HOA 16%, and BBOA 11%. The COA HR spectrum contained substantial signal from oxygenated ions (O:C: 0.21) whereas the HR HOA spectrum had almost exclusively contributions from chemically reduced ions (O:C: 0.03). If we assume that the carbon in HOA is fossil while that in COA and BBOA is modern, primary OA in Barcelona contains a surprisingly high fraction (59%) of non-fossil carbon. This paper presents a method for estimating cooking organic aerosol in ambient datasets based on the fractions of organic mass fragments at m/z 55 and 57: their data points fall into a V-shape in a scatter plot, with strongly influenced HOA data aligned to the right arm and strongly influenced COA data points aligned to the left arm. HR data show that this differentiation is mainly driven by the oxygen-containing ions C3H3O+ and C3H5O+, even though their contributions to m/z 55 and 57 are low compared to the reduced ions C4H7+ and C4H9+. A simple estimation method based on the markers m/z 55, 57, and 44 is developed here and allows for a first-order-estimation of COA in urban air. This study emphasizes the importance of cooking activities for ambient air quality and confirms the importance of chemical composition measurements with a high mass and time resolution.

Chemical Characterization of Submicron Aerosol Particles in Santiago de Chile

“…Fourth factor was found to contain elevated relative signal at m/z's 29, 60 and 73, suggesting the presence of wood combustion, likely from local domestic heating (Lanz et al, 2007;Aiken et al, 2008). That factor also contains elevated signal at m/z's 41, 43 and 55, which has been associated with cooking OA (COA), an important source of POA in urban environments like Zurich, Barcelona and Manchester (Lanz et al, 2007;Allan et al, 2010;Mohr et al, 2012). Mohr et al (2012) demonstrated that food charbroiling mass spectrum differs from HOA due to the oxygen-containing ions in the m/z's 43, 55 and 57, typical from fatty acids.…”

“…That factor also contains elevated signal at m/z's 41, 43 and 55, which has been associated with cooking OA (COA), an important source of POA in urban environments like Zurich, Barcelona and Manchester (Lanz et al, 2007;Allan et al, 2010;Mohr et al, 2012). Mohr et al (2012) demonstrated that food charbroiling mass spectrum differs from HOA due to the oxygen-containing ions in the m/z's 43, 55 and 57, typical from fatty acids. Moreover, in the food charbroiling mass spectra the m/z 43 presents higher relative signal than 41.…”

Formation of secondary organic aerosol coating on black carbon particles near vehicular emissions

“…The results of PMF illustrate that rBC-and HOA-rich factors accounted for about 60 and 20 wt % of rBC with a thin coating, respectively, and the rBC-rich factor contributed about 82 wt % of the freshly emitted rBC from traffic, similar to previous observations in the roadside environment . The COA factor is commonly observed in urban areas (Allan et al, 2010;Mohr et al, 2012) but its mixing with ambient rBC is seldom reported. The absence of a COA factor in rBC-containing particles highlights the fact that emissions of rBC from modern kitchens and the mixing of rBC and COA through particle coalescence were negligible in this study.…”

Organic aerosol composition and sources in Pasadena, California, during the 2010 CalNex campaign

“…This approach is a simplistic approximation, but the lower limit appears to be reasonable given that the diurnal cycles and spectral characteristics of CIOA are consistent with previous studies. In addition, comparison of the CIOA concentration against that predicted from the amount of organic mass measured by the AMS at m/z 55 following Mohr et al [2011] indicates that approximately 75% of CIOA is from cooking sources (see section D of the supporting information for the details of this comparison). A higher percentage up to almost 100% is also possible given the uncertainties in the comparison.…”

“…For HOA, O : C is relatively high (0.14) but not out of the range of previously reported values. For instance, O : C values as low as 0.02 (Riverside, CA) and 0.03 (Barcelona) [Docherty et al, 2011;Mohr et al, 2011] and as high as 0.16 (Mexico City) and 0.17 (Beijing) have been reported for HOA components [Aiken et al, 2009;Huang et al, 2010]. The diurnal cycle of HOA is similar to that of EC (and rBC) with a peak between 13:00 and 14:00 PDT (local time), and HOA and EC (and rBC) show high correlation (see Table D-1 in the supporting information and section 3.3 below).…”