A5074631406- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Atmospheric aerosols and clouds
- Air Quality Monitoring and Forecasting
- Air Quality and Health Impacts
- Atmospheric and Environmental Gas Dynamics
- Electron and X-Ray Spectroscopy Techniques
- Semiconductor materials and devices
- Surface and Thin Film Phenomena
- Marine and coastal ecosystems
- Smart Materials for Construction
- Cryospheric studies and observations
- Fire effects on ecosystems
- Copper-based nanomaterials and applications
- Aquatic Ecosystems and Phytoplankton Dynamics
- Catalytic Processes in Materials Science
- Plant responses to elevated CO2
- Phosphorus and nutrient management
- Copper Interconnects and Reliability
- ZnO doping and properties
- Electronic and Structural Properties of Oxides
- Insect and Pesticide Research
- Hemoglobin structure and function
- High-Temperature Coating Behaviors
- Lichen and fungal ecology
University of Helsinki
2014-2024
Paul Scherrer Institute
2008-2015
Tampere University
2005-2011
A list of authors and their affiliations appears at the end paper New-particle formation is a major contributor to urban smog1,2, but how it occurs in cities often puzzling3. If growth rates particles are similar those found cleaner environments (1-10 nanometres per hour), then existing understanding suggests that new should be rapidly scavenged by high concentration pre-existing particles. Here we show, through experiments performed under atmospheric conditions CLOUD chamber CERN, below...
Where is the Ce<sup>3+</sup>? Depth-profiling by <italic>in situ</italic> high-energy XPS provides an answer.
Surface oxidation of Cu(100) has been investigated by variable temperature scanning tunneling microscopy and quantitative x-ray photoelectron spectroscopy as a function O(2) pressure (8.0x10(-7) 3.7x10(-2) mbar) at 373 K. Three distinct phases in the initial have observed: (1) formation mixed oxygen chemisorption layer consisting Cu(100)-c(2x2)-O Cu(100)-(2sqrt[2]xsqrt[2])R45 degrees -O domains, (2) growth well-ordered (2sqrt[2]xsqrt[2])R45 degrees-O islands, (3) onset subsurface oxide...
Nano-structured and porous foams derived from crosslinked cellulose nanofibers (CNF) were designed tailored as highly efficient aerosol filters. The lignin-containing CNF was prepared a recycled milk-container board using deep eutectic solvent pretreatment mechanical grinding. nanofoams or aerogels formed in different densities (initial concentration of 0.2–1.0 wt%) with freeze-drying process two silane compounds for strengthening the structure. filtration performance studied Differential...
Abstract. The formation of ice particles in Earth's atmosphere strongly influences the dynamics and optical properties clouds their impacts on climate system. Ice is often triggered heterogeneously by ice-nucleating (INPs) that represent a very low number atmosphere. To date, many sources INPs, such as mineral soil dust, have been investigated identified mid latitudes. Although less known about nucleation at high latitudes, efforts made to identify INPs Arctic boreal environments. In this...
Inhomogeneities in temperature and ammonia concentrations can cause rapid growth of nanoparticles polluted environments.
Abstract. Atmospheric soluble organic aerosol material can become solid or semi-solid. Due to increasing viscosity and decreasing diffusivity, this impact important processes such as gas uptake reactivity within aerosols containing substances. This work explores the dependence of shikimic acid ozonolysis on humidity thereby viscosity. Shikimic acid, a proxy for oxygenated reactive material, reacts with O3 in Criegee-type reaction. We used an environmental microreactor embedded scanning...
Illustration of how ammonium nitrate formation can cause rapid growth nucleating particles, increasing survival particles in polluted conditions.
Surface oxidation of Cu(100) in O(2) has been investigated situ by x-ray photoelectron spectroscopy, induced Auger electron spectroscopy (XAES), and scanning tunneling microscopy (STM) as a function surface temperature (T(S)=303-423 K) pressure (p(O(2) )=3.7 x 10(-2)-213 mbars). Morphology the oxide on near layers is characterized utilizing STM inelastic background XAES O KLL signal. Analysis peak shape Cu LMM facilitates quantification Cu, Cu(2)O, CuO concentrations. The authors conclude...
Heterogeneous reactions of nitrogen oxides on metal oxide surfaces have been suggested to play a significant role in environmental chemistry, physics, and engineering. Many the compounds found among atmospheric mineral dust particles are inherently semiconducting substrates. Due their low band gap, they effective photoactive materials environmentally relevant ultraviolet (UVA) range solar radiation. Here, we studied species evolution photochemistry TiO2(110) context chemistry by means near...
Abstract. Atmospheric observations in remote locations offer a possibility of exploring trace gas and particle concentrations pristine environments. However, data from areas are often contaminated by pollution local sources. Detecting this contamination is thus central frequently encountered issue. Consequently, many different methods exist today to identify atmospheric composition measurement time series, but no single method has been widely accepted. In study, we present new primary...
Abstract. Several studies have investigated new particle formation (NPF) events from various sites ranging pristine locations, including forest sites, to urban areas. However, there is still a dearth of investigating NPF processes and subsequent aerosol growth in coastal yet semi-urban where the tropospheric layer concoction biogenic anthropogenic gases particles. The investigation factors leading becomes extremely complex due highly dynamic meteorological conditions at coastline especially...
Abstract Surface oxidation of Fe‐19Cr‐17Ni, Fe‐19Cr‐18Ni‐1Al and TiC‐enriched alloys was investigated by photoelectron spectroscopy (PES). The experiments were conducted at 323 K in pure O 2 (2.7 × 10 −6 mbar). Composition morphology the nanoscale surface oxides determined quantitatively inelastic electron background analysis. Moreover, use synchrotron radiation facilities necessary to obtain improved sensitivity for studying minor alloying elements such as Al Si. results indicate...
Abstract. The occurrence of new particle formation (NPF) events detected in a coastal agricultural site, at Qvidja, Southwestern Finland, was investigated using the data measured with nitrate ion-based chemical-ionization atmospheric-pressure-interface time-of-flight (CI-APi-TOF) mass spectrometer. binned positive matrix factorization method (binPMF) applied to spectra. It resulted eight factors describing time series ambient gas and cluster composition Qvidja during spring 2019. most...
Abstract Isolation of extracellular vesicles (EV) has been developing rapidly in parallel with the interest EVs. However, commonly utilized protocols may not suit more challenging sample matrixes and could potentially yield suboptimal results. Knowing assessing pitfalls isolation procedure to be used, should involved some extent for EV analytics. EVs cow milk are great due their abundancy large‐scale availability as well cross‐species bioavailability possible use drug carriers....
The design and performance of an x-ray photoelectron spectroscopy (XPS)–scanning tunneling microscopy (STM) surface analysis system for studying nanostructured materials are described. features electron methods (XPS Auger spectroscopy) in addition to a variable temperature STM. With the analytical system, chemical as well morphology down atomic resolution can be obtained. also provides facilities sample cleaning, annealing, gas dosing, depth profiling, modifications by sputtering...
Ultrafine particles (UFP, <100 nm) often dominate the aerosol number concentration in urban environments. The resulting high particle concentrations can be as 106 cm−3. Such are a challenge for instruments, measurements based on condensation counters, typically designed to sensitive lower concentrations. Therefore, diluter is employed down measurement range of instrument. However, diluters unsuitable measuring cluster or nucleation mode due losses. Here, we present new Airmodus nanoparticle...
Agriculture provides people with food, but poses environmental challenges. Via comprehensive observations on an agricultural land at Qvidja in Southern Finland, we were able to show that soil-emitted compounds (mainly ammonia and amines), together available sulfuric acid, form new aerosol particles which then grow climate-relevant sizes by the condensation of extremely low volatile organic originating from a side production photosynthesis (compounds emitted ground surrounding vegetation). We...
Abstract Ozone adsorption and decomposition on metal oxides is of wide interest in technology atmospheric chemistry. Here, ozone‐adsorption‐induced band bending observed Ti‐ Fe‐oxide model surfaces under dry humid conditions. Photoelectron spectroscopic studies indicate the effect charge transfer to O 3 , which limits surface coverage precursor reactions. This also consistent with negative pressure dependence previous studies. These results contribute our fundamental understanding ozone...