Real time chemical characterization of local and regional nitrate aerosols

Dall’Osto, Manuel; Harrison, Roy M.; Coe, Hugh; Williams, P. I.; Allan, J. D.

doi:10.5194/acp-9-3709-2009

Cited by 84 publications

(80 citation statements)

References 49 publications

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“…This analysis complements the studies of Dall'Osto et al (2009a) concerning a fog event and of Dall'Osto et al (2009b) concerning different types of nitrate containing particles (and their atmospheric behaviour). Table 1 summarizes the 15 clusters found during the REPARTEE I field study.…”

Section: Dall'osto and R M Harrison: Urban Organic Aerosolssupporting

confidence: 52%

Urban organic aerosols measured by single particle mass spectrometry in the megacity of London

Dall’Osto

Harrison

2012

Atmos. Chem. Phys.

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Abstract. During the month of October 2006, as part of the REPARTEE-I experiment (Regent's Park and Tower Environmental Experiment) an Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) was deployed at an urban background location in the city of London, UK. Fifteen particle types were classified, some of which were already discussed (Dall'Osto et al., 2009a,b;Harrison et al., 2012). In this manuscript the origins and properties of four unreported particle types postulated to be due to locally generated aerosols, independent of the air mass type advected into London, are examined. One particle type, originating from lubricating oil (referred to as Ca-EC), was associated with morning rush hour traffic emissions. A second particle type, composed of both inorganic and organic species (called Na-EC-OC), was found enhanced in particle number concentration during evening time periods, and is likely to originate from a source operating at this time of day, or more probably from condensation of semi-volatile species. A third class, internally mixed with organic carbon and sulphate (called OC), was found to spike both in the morning and evenings although it could not unambiguously associated with a specific source or atmospheric process. The fourth class (Secondary Organic Aerosols -Polycyclic Aromatic Hydrocarbon; SOA-PAH) exhibited maximum frequency during the warmest part of the day, and a number of factors point towards secondary aerosol production from traffic-related volatile aromatic compounds. Single particle mass spectra of this particle type showed an oxidized polycyclic aromatic compound signature. A comparison of ATOFMS particle class data is then made with factors obtained by Positive Matrix Factorization and PAH signatures obtained from Aerosol Mass Spectrometer (AMS) data (Allan et al., 2010). Both the Ca-EC and OC particle types correlate with primary Hydrocarbon-like Organic Aerosol (HOA, R 2 = 0.65 and 0.50 respectively), and Na-EC-OC correlates weakly with the AMS secondary Oxygenated Organic Aerosol (OOA), (R 2 = 0.35). Cluster SOA-PAH was found not to correlate with any AMS signal. A detailed analysis was conducted to identify ATOFMS particle type(s) representative of the AMS cooking aerosol factor (COA), but no convincing associations were found. The combined ATOFMS and AMS results of this REPARTEE study do not always provide an entirely coherent interpretation.

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Section: Dall'osto and R M Harrison: Urban Organic Aerosolssupporting

confidence: 52%

Urban organic aerosols measured by single particle mass spectrometry in the megacity of London

Dall’Osto

Harrison

2012

Atmos. Chem. Phys.

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“…Figure 10 shows that with this assumption the simulated concentrations and diurnal cycle of nitrate and ammonium are approximately consistent with observations from ICG-2 Jülich in the dry period. Note that a similar daily aerosol nitrate cycle and good correlation with RH has been observed in an urban background location near London (UK) (Dall'Osto et al, 2009;their Fig. 6).…”

Section: Sensitivity Studymentioning

confidence: 69%

Evaluation of simulated aerosol properties with the aerosol-climate model ECHAM5-HAM using observations from the IMPACT field campaign

et al. 2010

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Abstract. In May 2008, the measurement campaign IM-PACT for observation of atmospheric aerosol and cloud properties was conducted in Cabauw, The Netherlands. With a nudged version of the coupled aerosol-climate model ECHAM5-HAM we simulate the size distribution and chemical composition of the aerosol and the associated aerosol optical thickness (AOT) for the campaign period. Synoptic scale meteorology is represented realistically through nudging of the vorticity, the divergence, the temperature and the surface pressure. Simulated concentrations of aerosol sulfate and organics at the surface are generally within a factor of two from observed values. The monthly averaged AOT from the model is 0.33, about 20% larger than observed. For selected periods of the month with relatively dry and moist conditions discrepancies are approximately −30% and +15%, respectively. Discrepancies during the dry period are partly caused by inaccurate representation of boundary layer (BL) dynamics by the model affecting the simulated AOT. The model simulates too strong exchange between the BL and the free troposphere, resulting in weaker concentration gradients at the BL top than observed for aerosol and humidity, while upward mixing from the surface layers into the BL appears to be underestimated. The results indicate that beside aerosol sulfate and organics also aerosol ammonium and nitrate sigCorrespondence to: G. J. Roelofs (g.j.h.roelofs@uu.nl) nificantly contribute to aerosol water uptake. The simulated day-to-day variability of AOT follows synoptic scale advection of humidity rather than particle concentration. Even for relatively dry conditions AOT appears to be strongly influenced by the diurnal cycle of RH in the lower boundary layer, further enhanced by uptake and release of nitric acid and ammonia by aerosol water.

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“…Nitrate aerosols have been found to be at least as important as sulfate in some regions of Europe (ten Brink et al, 1996;Schaap et al, 2004) and some urban areas (Malm et al, 2004). Nitrate is internally mixed with sulfate, ammonium, elemental and organic carbon in western Europe (Dall'Osto et al, 2009) and in the Amazon basin (Trebs et al, 2005). However, aerosol nitrate is not just associated with ammonium in the accumulation mode.…”

Section: Xu and J E Penner: Global Simulations Of Nitrate And Ammentioning

confidence: 99%

Global simulations of nitrate and ammonium aerosols and their radiative effects

2012

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Abstract.We examine the formation of nitrate and ammonium on five types of externally mixed pre-existing aerosols using the hybrid dynamic method in a global chemistry transport model. The model developed here predicts a similar spatial pattern of total aerosol nitrate and ammonium to that of several pioneering studies, but separates the effects of nitrate and ammonium on pure sulfate, biomass burning, fossil fuel, dust and sea salt aerosols. Nitrate and ammonium boost the scattering efficiency of sulfate and organic matter but lower the extinction of sea salt particles since the hygroscopicity of a mixed nitrate-ammonium-sea salt particle is less than that of pure sea salt. The direct anthropogenic forcing of particulate nitrate and ammonium at the top of the atmosphere (TOA) is estimated to be −0.12 W m −2 . Nitrate, ammonium and nitric acid gas also affect aerosol activation and the reflectivity of clouds. The first aerosol indirect forcing by anthropogenic nitrate (gas plus aerosol) and ammonium is estimated to be −0.09 W m −2 at the TOA, almost all of which is due to condensation of nitric acid gas onto growing droplets (−0.08 W m −2 ).

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Real time chemical characterization of local and regional nitrate aerosols

Cited by 84 publications

References 49 publications

Urban organic aerosols measured by single particle mass spectrometry in the megacity of London

Urban organic aerosols measured by single particle mass spectrometry in the megacity of London

Evaluation of simulated aerosol properties with the aerosol-climate model ECHAM5-HAM using observations from the IMPACT field campaign

Global simulations of nitrate and ammonium aerosols and their radiative effects

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