Publications by authors named "Luis Barreira"

Article Synopsis
  • Brown carbon (BrC) is a type of organic aerosol that absorbs light in the UV-Vis spectrum, influencing climate, but its full effects are not well understood due to limited knowledge on its chemistry and atmospheric behavior over time.
  • This study focused on measuring BrC in particulate matter from winter emissions in Helsinki, specifically in areas influenced by wood combustion, using advanced techniques to analyze its sources, chemical composition, and the extent of light absorption.
  • Findings indicated that BrC significantly contributed to light absorption, especially in residential areas, with biomass burning being the primary source, while the research also highlighted variances in absorption characteristics and the uncertainties related to measuring these properties.
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Vehicular emissions deteriorate air quality in urban areas notably. The aim of this study was to conduct an in-depth characterization of gaseous and particle emissions, and their potential to form secondary aerosol emissions, of the cars meeting the most recent emission Euro 6d standards, and to investigate the impact of fuel as well as engine and aftertreatment technologies on pollutants at warm and cold ambient temperatures. Studied vehicles were a diesel car with a diesel particulate filter (DPF), two gasoline cars (with and without a gasoline particulate filter (GPF)), and a car using compressed natural gas (CNG).

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Recent studies indicate that monitoring only fine particulate matter (PM) may not be enough to understand and tackle the health risk caused by particulate pollution. Health effects per unit PM seem to increase in countries with low PM, but also near local pollution sources (e.g.

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The differences in the traffic fuels have been shown to affect exhaust emissions and their toxicity. Especially, the aromatic content of diesel fuel is an important factor considering the emissions, notably particulate matter (PM) concentrations. The ultra-fine particles (UFP, particles with a diameter of <100 nm) are important components of engine emissions and connected to various health effects, such as pulmonary and systematic inflammation, and cardiovascular disorders.

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Urban air fine particles are a major health-relating problem. However, it is not well understood how the health-relevant features of fine particles should be monitored. Limitations of PM (mass concentration of sub 2.

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The ageing of the population poses urgent challenges to the health and social protection sectors, including the need for greater adequacy and integration of health care services provided to older people. It is considered necessary and urgent to understand the state-of-the-art of community-based models of care for older people in institutional care and at home. This study aims to map the concepts that politicians and providers need to address through an umbrella review as a review method.

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Amines are recognized as key compounds in new particle formation (NPF) and secondary organic aerosol (SOA) formation. In addition, ozonolysis of α-pinene contributes substantially to the formation of biogenic SOAs in the atmosphere. In the present study, ozonolysis of α-pinene in the presence of dimethylamine (DMA) was investigated in a flow tube reactor.

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Pinonaldehyde, which is among the most abundant oxidation products of α-pinene, and dimethylamine were selected to study the formation of N-containing low volatile compounds from aldehyde-amine reactions in the atmosphere. Gas phase reactions took place in a Tedlar bag, which was connected to a mass spectrometer ionization source via a short deactivated fused silica column. In addition to on-line analysis, abundance of gaseous precursors and reaction products were monitored off-line.

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We introduce the mathematical concept of multifractality and describe various multifractal spectra for dynamical systems, including spectra for dimensions and spectra for entropies. We support the study by providing some physical motivation and describing several nontrivial examples. Among them are subshifts of finite type and one-dimensional Markov maps.

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