Source apportionment of the submicron organic aerosols over the Atlantic Ocean from 53° N to 53° S using HR-ToF-AMS

Abstract

PM1 filter samples with a sampling time of 24 hours. Our measurements show that the MBL aerosol particle mass is controlled by sulfate (50%), followed by organics (21%), sea salt (12%), ammonium (9%), Black Carbon (BC, 5%) and nitrate (3%). Only sulfate exhibits pronouncedly seasonal dependency, while no such trend was observed in other species.Source apportionment of the organic fraction was performed using Positive Matrix Factorization (PMF). Five factors were 20 identified, including three marine sources and two non-marine sources. Marine sources are linked to primary production (19% of total organic aerosol (OA) mass), marine dimethylsulfide (DMS)-oxidation (16%), and amine-related secondary formation (16%). The other two OA components are attributed to continental outflow (19%) and aged ship exhausts -biomass burning emissions (30%). Our study indicates that, on average, non-marine sources nearly have the equal importance to the Atlantic aerosols comparing with the marine sources, respectively contributing 49% and 51% to the total OA mass loadings. The 25 South Atlantic atmosphere is found to be less polluted than the North according to our source analysis. Detailed latitudinal distribution of OA sources showed that DMS oxidation contributes remarkably to the MBL aerosol over the South Atlantic during spring, while continental pollutants largely contaminate the marine atmosphere when near the west and middle Africa (15°N~15°S) as well as Europe. Based on our measurements, SOA produced from DMS oxidation over the Atlantic can be estimated as MSA mass concentration times a scaling factor 1.79 for spring season, which is derived from the strong 30 correlation (R 2 >0.85) between MSA and DMS-oxidation OA component.Atmos. Chem. Phys. Discuss., https://doi

African volcanic emissions influencing atmospheric aerosols over the Amazon rain forest

“…During African dust advection periods when mineral dust particles are usually mixed with BB emissions and sea-salt aerosol particles, Moran-Zuloaga et al (2017) measured sulfate mass concentrations of ∼ 0.44 µg m −3 using energy-dispersive X-ray analysis and M. L. reported a M sulfate of ∼ 0.25 ± 0.19 µg m −3 measured by ACSM; both studies were conducted at the ATTO site. All these values and also measurements over the South Atlantic Ocean (Huang et al, 2018) were well below the M sulfate median values measured at ATTO between 21 and 30 September 2014 (1.60 µg m −3 ; see Fig. 2a).…”

Effects of continental emissions on Cloud Condensation Nuclei (CCN) activity in northern South China Sea during summertime 2018

“…The average mass fraction of NR-PM 1 during the campaign was dominated by sulfate (46%), followed by organics (35%), ammonium (14%), nitrate (3%), and chloride (2%), which was similar to the measurement over the Atlantic Ocean (Huang et al, 2018). The chemical composition over northern SCS was quite different from that at the urban site which was dominated by organics largely from anthropogenic sources (Cai et al, 2017).…”

“…Remote sensing and ship-based cruise methods are two typical approaches employed to measure aerosol properties in marine environments (Durkee et al, 1986;Kim et al, 2009;Lehahn et al, 2010;Huang et al, 2018). Compared to ship-based measurements, remote sensing covers spatially a larger area and temporally a longer period which are essential in the characterization of marine aerosols.…”

“…Although ship-based measurements are limited in spatial coverage, they can provide higher spatial and temporal resolution for obtaining comprehensive physical and chemical properties of gas and aerosol particles. Huang et al (2018) measured chemical composition of particles with a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) over the Atlantic Ocean aboard a campaign ship and found that about 19% of organics originated from continental long-range transport. Kim et al (2009) found that particle size distribution varied in a dynamic range, depending on the meteorological conditions over the Yellow Sea and the East China Sea.…”