Comparative Assessment of Cooking Emission Contributions to Urban Organic Aerosol Using Online Molecular Tracers and Aerosol Mass Spectrometry Measurements

Author(s):  
Dan Dan Huang ◽  
Shuhui Zhu ◽  
Jingyu An ◽  
Qiongqiong Wang ◽  
Liping Qiao ◽  
...  
2011 ◽  
Vol 45 (15) ◽  
pp. 6329-6335 ◽  
Author(s):  
Lea Hildebrandt ◽  
Kaytlin M. Henry ◽  
Jesse H. Kroll ◽  
Douglas R. Worsnop ◽  
Spyros N. Pandis ◽  
...  

2007 ◽  
Vol 7 (3) ◽  
pp. 8617-8662 ◽  
Author(s):  
N. Hock ◽  
J. Schneider ◽  
S. Borrmann ◽  
A. Römpp ◽  
G. Moortgat ◽  
...  

Abstract. Detailed investigations of the chemical and microphysical properties of rural continental aerosols were performed during the HAZE2002 experiment, which was conducted in May 2002 at the Meteorological Observatory Hohenpeissenberg (DWD) in Southern Germany. The online measurement data and techniques included: size-resolved chemical composition of submicron particles by aerosol mass spectrometry (AMS); total particle number concentrations and size distributions over the diameter range of 3 nm to 9 μm (CPC, SMPS, OPC); monoterpenes determined by gas chromatography- ion trap mass spectrometry; OH and H2SO4 determined by atmospheric pressure chemical ionization mass spectrometry (CIMS). Filter sampling and offline analytical techniques were used to determine: fine particle mass (PM2.5), organic, elemental and total carbon in PM2.5 (OC2.5, EC2.5, TC2.5), and selected organic compounds (dicarboxylic acids, polycyclic aromatic hydrocarbons, proteins). Overall, the non-refractory components of submicron particles detected by aerosol mass spectrometry (PM1, 6.6±5.4 μg m−3, arithmetic mean and standard deviation) accounted for ~62% of PM2.5 determined by filter gravimetry (10.6±4.7 μg m−3). The relative proportions of non-refractory submicron particle components were: 11% ammonium, 19% nitrate, 20% sulfate, and 50% organics (OM1). In spite of strongly changing meteorological conditions and absolute concentration levels of particulate matter (3–13 μg m−3 PM1), OM1 was closely correlated with PM1 (r2=0.9) indicating a near-constant ratio of non-refractory organics and inorganics. In contrast, the ratio of nitrate to sulfate was highly dependent on temperature (14–32°C) and relative humidity (20–100%), which could be explained by thermodynamic model calculations of NH3/HNO3/NH4NO3 gas-particle partitioning. From the combination of optical and other sizing techniques (OPC, AMS, SMPS), an average refractive index of 1.40–1.45 was inferred for the measured rural aerosol particles. The average ratio of OM1 to OC2.5 was 2, indicating a high proportion of heteroelements in the organic fraction of the sampled rural aerosol. This is consistent with the high ratio of oxygenated organic aerosol (OOA) over hydrocarbon-like organic aerosol (HOA) inferred from the AMS results (4:1), and also with the high abundance of proteins (~3%) indicating a high proportion of primary biological material (~30%) in PM2.5. Moreover, the low abundance of PAHs (<1 ng m−3) and EC (<1 μg m−3) in PM2.5 confirm a low contribution of combustion emissions, which are usually also major sources for HOA. Slightly enhanced HOA concentrations indicating fresh anthropogenic emissions were observed during a period when air masses were advected from the densely populated Po Valley, Italy. Detection of several secondary organic aerosol compounds (dicarboxylic acids) and their precursors (monoterpenes) confirmed the finding that secondary aerosol from natural sources was an important aerosol constituent. A sharp decrease of the short lived monoterpenes indicated that during night-time the measurement station was isolated from ground emission sources by a stable inversion layer. Nighttime values can therefore be regarded to represent regional or long range transport. New particle formation was observed almost every day with particle number concentrations exceeding 104 cm−3 (nighttime background level 1000–2000 cm−3). Closer inspection of two major events indicated that ternary H2SO4/H2O/NH3 nucleation triggered particle formation and that condensation of both organic and inorganic species contributed to particle growth.


2010 ◽  
Vol 40 (10) ◽  
pp. 1550-1557
Author(s):  
YuanHang ZHANG ◽  
Lian XUE ◽  
LingYan HE ◽  
QiJing BIAN ◽  
Min HU ◽  
...  

2010 ◽  
Vol 10 (21) ◽  
pp. 10453-10471 ◽  
Author(s):  
V. A. Lanz ◽  
A. S. H. Prévôt ◽  
M. R. Alfarra ◽  
S. Weimer ◽  
C. Mohr ◽  
...  

Abstract. Real-time measurements of non-refractory submicron aerosols (NR-PM1) were conducted within the greater Alpine region (Switzerland, Germany, Austria, France and Liechtenstein) during several week-long field campaigns in 2002–2009. This region represents one of the most important economic and recreational spaces in Europe. A large variety of sites was covered including urban backgrounds, motorways, rural, remote, and high-alpine stations, and also mobile on-road measurements were performed. Inorganic and organic aerosol (OA) fractions were determined by means of aerosol mass spectrometry (AMS). The data originating from 13 different field campaigns and the combined data have been utilized for providing an improved temporal and spatial data coverage. The average mass concentration of NR-PM1 for the different campaigns typically ranged between 10 and 30 μg m−3. Overall, the organic portion was most abundant, ranging from 36% to 81% of NR-PM1. Other main constituents comprised ammonium (5–15%), nitrate (8–36%), sulfate (3–26%), and chloride (0–5%). These latter anions were, on average, fully neutralized by ammonium. As a major result, time of the year (winter vs. summer) and location of the site (Alpine valleys vs. Plateau) could largely explain the variability in aerosol chemical composition for the different campaigns and were found to be better descriptors for aerosol composition than the type of site (urban, rural etc.). Thus, a reassessment of classifications of measurements sites might be considered in the future, possibly also for other regions of the world. The OA data was further analyzed using positive matrix factorization (PMF) and the multi-linear engine ME (factor analysis) separating the total OA into its underlying components, such as oxygenated (mostly secondary) organic aerosol (OOA), hydrocarbon-like and freshly emitted organic aerosol (HOA), as well as OA from biomass burning (BBOA). OOA was ubiquitous, ranged between 36% and 94% of OA, and could be separated into a low-volatility and a semi-volatile fraction (LV-OOA and SV-OOA) for all summer campaigns at low altitude sites. Wood combustion (BBOA) accounted for a considerable fraction during wintertime (17–49% OA), particularly in narrow Alpine valleys BBOA was often the most abundant OA component. HOA/OA ratios were comparatively low for all campaigns (6–16%) with the exception of on-road, mobile measurements (23%) in the Rhine Valley. The abundance of the aerosol components and the retrievability of SV-OOA and LV-OOA are discussed in the light of atmospheric chemistry and physics.


2013 ◽  
Vol 13 (9) ◽  
pp. 4997-5015 ◽  
Author(s):  
M. Dall'Osto ◽  
J. Ovadnevaite ◽  
D. Ceburnis ◽  
D. Martin ◽  
R. M. Healy ◽  
...  

Abstract. Ambient wintertime background urban aerosol in Cork city, Ireland, was characterized using aerosol mass spectrometry. During the three-week measurement study in 2009, 93% of the ca. 1 350 000 single particles characterized by an Aerosol Time-of-Flight Mass Spectrometer (TSI ATOFMS) were classified into five organic-rich particle types, internally mixed to different proportions with elemental carbon (EC), sulphate and nitrate, while the remaining 7% was predominantly inorganic in nature. Non-refractory PM1 aerosol was characterized using a High Resolution Time-of-Flight Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS) and was also found to comprise organic aerosol as the most abundant species (62%), followed by nitrate (15%), sulphate (9%) and ammonium (9%), and chloride (5%). Positive matrix factorization (PMF) was applied to the HR-ToF-AMS organic matrix, and a five-factor solution was found to describe the variance in the data well. Specifically, "hydrocarbon-like" organic aerosol (HOA) comprised 20% of the mass, "low-volatility" oxygenated organic aerosol (LV-OOA) comprised 18%, "biomass burning" organic aerosol (BBOA) comprised 23%, non-wood solid-fuel combustion "peat and coal" organic aerosol (PCOA) comprised 21%, and finally a species type characterized by primary \\textit{m/z}~peaks at 41 and 55, similar to previously reported "cooking" organic aerosol (COA), but possessing different diurnal variations to what would be expected for cooking activities, contributed 18%. Correlations between the different particle types obtained by the two aerosol mass spectrometers are also discussed. Despite wood, coal and peat being minor fuel types used for domestic space heating in urban areas, their relatively low combustion efficiencies result in a significant contribution to PM1 aerosol mass (44% and 28% of the total organic aerosol mass and non-refractory total PM1, respectively).


2013 ◽  
Vol 13 (2) ◽  
pp. 3533-3573 ◽  
Author(s):  
Y. J. Li ◽  
B. Y. L. Lee ◽  
J. Z. Yu ◽  
N. L. Ng ◽  
C. K. Chan

Abstract. The chemical characteristics of organic aerosol (OA) are still poorly constrained. Here we present observation results of the degree of oxygenation of OA based on high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS) measurements made at a coastal site in Hong Kong from late April to the end of May in 2011. Two foggy periods and one hazy period were chosen for detailed analysis to compare the changes in the degree of oxygenation of OA due to different processes. The Extended Aerosol Inorganic Model (E-AIM) predicted a fine particle liquid water content (LWCfp) up to 85 μg m−3 during the foggy days. Particle concentration as measured by HR-ToF-AMS was up to 60 μg m−3 during the hazy days and up to 30 μg m−3 during the foggy days. The degree of oxygenation of OA, as indicated by several parameters including the fraction of m/z 44 in organic mass spectra (f44), the elemental ratio of oxygen to carbon (O : C), and the carbon oxidation state (OSc), was evaluated against the odd oxygen (Ox) concentration, LWCfp, ionic strength (IS), and in-situ pH (pHis). Results suggest that the high concentration of OA (on average 11 μg m−3) and the high degree of oxygenation (f44 = 0.15, O : C = 0.51, and OSc = −0.31) during the hazy period were mainly due to gas-phase oxidation. During the foggy periods with low photochemical activities, the degree of oxygenation of OA was almost as high as that on the hazy days and significantly higher than that during non-foggy/non-hazy days. However, the OA evolved quite differently in the two foggy periods. The first foggy period in late April saw a larger LWCfp and a lower Ox concentration and the OA was made up of ~ 20% semi-volatile oxygenated organic aerosol (SVOOA) as resolved by positive matrix factorization (PMF). In the second foggy period in mid-May, higher Ox concentration and lower LWCfp were observed, and the OA was found to contain >50% low-volatility oxygenated organic aerosols (LVOOA). An examination of the particle-phase constituents suggests that partitioning may have been the dominating process through which oxygenated species were incorporated into the particle phase during the first foggy period, while oxidation in the aqueous phase may have been the dominating process during the second foggy period. Both physical and chemical processes were found to be important for oxygenated OA formation.


2017 ◽  
Vol 14 (2) ◽  
pp. 75 ◽  
Author(s):  
Wenzheng Fang ◽  
Lei Gong ◽  
Liusi Sheng

Environmental contextSecondary organic aerosol, formed by oxidation of volatile precursors such as monoterpenes, is a major contributor to the total atmospheric organic aerosol. We focus on the online mass spectrometric analysis of the aerosol generated by oxidation products of four major monoterpenes in an environmental chamber. Numerous important monoterpene oxidation products were clearly observed and provided a direct comparison of the formation of biogenic secondary organic aerosols. AbstractWe present here thermal desorption–tunable vacuum ultraviolet time-of-flight photoionisation aerosol mass spectrometry (TD-VUV-TOF-PIAMS) for online analysis of biogenic secondary organic aerosols (BSOAs) formed from OH-initiated photooxidation and dark ozonolysis of α-pinene, β-pinene, Δ3-carene and d-limonene in smog chamber experiments. The ‘soft’ ionisation at near-threshold photon energies (≤10.5eV) used in this study permits direct measurement of the fairly clean mass spectra, facilitating molecular identification. The online BSOA mass spectra compared well with previous offline measurements and most of the important monoterpene oxidation products were clearly found in the online mass spectra. Oxidation products such as monoterpene-derived acids (e.g. pinic acid, pinonic acid, 3-caronic acid, limononic acid, limonalic acid), ketones (e.g. norpinone, limonaketone), aldehydes (e.g. caronaldehyde, norcaronaldehyde, limononaldehyde) and multifunctional organics (e.g. hydroxypinonaldehydes, hydroxy-3-caronic aldehydes, hydroxylimononic acid) were tentatively identified. The online TD-VUV-TOF-PIAMS mass spectra showed that the OH-initiated photooxidation and ozonolysis of the same monoterpenes produced some similar BSOA products; for example, 3-caric acid, 3-caronic acid, 3-norcaronic acid, 3-norcaralic acid, caronaldehyde and norcaronaldehyde were observed in both photooxidation and ozonolysis of Δ3-carene. However, they could be formed through different pathways. Some of the same products and isomers (e.g. 10-oxopinonic acid, pinonic acid, norpinic acid, hydroxyl pinonaldehyde, norpinonic acid, norpinone) were formed during the photooxidation and ozonolysis of α-pinene and β-pinene. However, several different BSOA products were generated in these photooxidation and ozonolysis reactions due to their different parent structures. The OH–monoterpene reaction generated higher-molecular-weight products than O3–monoterpene owing to multiple OH additions to the unsaturated carbon bond. The online observation of key BSOA products provided a direct comparison of BSOA formation among different monoterpenes and insights into the formation pathways in the OH-initiated photooxidation and ozonolysis of monoterpenes.


2010 ◽  
Vol 3 (4) ◽  
pp. 1175-1183 ◽  
Author(s):  
S. Geddes ◽  
B. Nichols ◽  
K. Todd ◽  
J. Zahardis ◽  
G. A. Petrucci

Abstract. A new method, near-infrared laser desorption/ionization aerosol mass spectrometry (NIR-LDI-AMS), is described for the real time analysis of organic aerosols at atmospherically relevant total mass loadings. Particles are sampled with an aerodynamic lens onto an aluminum probe. A moderate energy NIR laser pulse at 1064 nm is directed onto the probe to vaporize and ionize particle components. Delayed pulse extraction is then used to sample the ions into a reflectron time of flight mass spectrometer for chemical analysis. The soft ionization afforded by the NIR photons results in minimal fragmentation (loss of a hydrogen atom) producing intact pseudo-molecular anions at [M-H]−. The limit of detection measured for pure oleic acid particles (geometric mean diameter and standard deviation of 180 nm and 1.3, respectively) was 140 fg (or 1.7 ng m−3 per minute sampling time). As an example of the utility of NIR-LDI-AMS to measurements of atmospheric importance, the method was applied to laboratory chamber measurements of the secondary organic aerosol formation from ozonolysis of α-pinene. High quality mass spectra were recorded with a 2-min time resolution for total aerosol mass loadings ranging from 1.5 to 8.7 μg m−3. These results demonstrate the potential of NIR-LDI-AMS to allow for more accurate measurements of the organic fraction of atmospheric particulate at realistic mass loadings. Measurements at ambient-levels of SOA mass loading are important to improve parameterizations of chamber-based SOA formation for modeling regional and global SOA fluxes and to aid in remediating the discrepancy between modeled and observed atmospheric total SOA production rates and concentrations.


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