Author
Jarkko V. Niemi
Bio: Jarkko V. Niemi is an academic researcher from University of Helsinki. The author has contributed to research in topics: Aerosol & Air quality index. The author has an hindex of 25, co-authored 75 publications receiving 1831 citations.
Papers published on a yearly basis
Papers
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TL;DR: It is shown that a major fraction of particles emitted by road transportation are in a previously unmeasured size range of 1.3–3.0 nm, implying that in urban areas, an atmospheric nucleation process is not necessary for the formation of a large number of particles that affect population health and climate.
Abstract: In densely populated areas, traffic is a significant source of atmospheric aerosol particles. Owing to their small size and complicated chemical and physical characteristics, atmospheric particles resulting from traffic emissions pose a significant risk to human health and also contribute to anthropogenic forcing of climate. Previous research has established that vehicles directly emit primary aerosol particles and also contribute to secondary aerosol particle formation by emitting aerosol precursors. Here, we extend the urban atmospheric aerosol characterization to cover nanocluster aerosol (NCA) particles and show that a major fraction of particles emitted by road transportation are in a previously unmeasured size range of 1.3-3.0 nm. For instance, in a semiurban roadside environment, the NCA represented 20-54% of the total particle concentration in ambient air. The observed NCA concentrations varied significantly depending on the traffic rate and wind direction. The emission factors of NCA for traffic were 2.4·1015 (kgfuel)-1 in a roadside environment, 2.6·1015 (kgfuel)-1 in a street canyon, and 2.9·1015 (kgfuel)-1 in an on-road study throughout Europe. Interestingly, these emissions were not associated with all vehicles. In engine laboratory experiments, the emission factor of exhaust NCA varied from a relatively low value of 1.6·1012 (kgfuel)-1 to a high value of 4.3·1015 (kgfuel)-1 These NCA emissions directly affect particle concentrations and human exposure to nanosized aerosol in urban areas, and potentially may act as nanosized condensation nuclei for the condensation of atmospheric low-volatile organic compounds.
172 citations
TL;DR: The American Geophysical Union published a paper as discussed by the authors, which is a summary of the previous year's conference proceedings, including the results of this paper.Reproduced by permission of American Geographical
Abstract: Published 2005 American Geophysical Union.
Reproduced by permission of American Geophysical
Union.
125 citations
TL;DR: In this article, the authors measured equivalent black carbon (eBC) using an aethalometer (AE33) at three different locations in the Helsinki metropolitan area, Finland from October 2015 to May 2017.
106 citations
Queensland University of Technology1, University of Queensland2, University of Toronto3, Nanjing University4, Shanghai University5, Finnish Meteorological Institute6, University of Helsinki7, University of Milano-Bicocca8, University of Molise9, University of Naples Federico II10, Spanish National Research Council11, University of Birmingham12, University of Southern California13
TL;DR: It is demonstrated that a high PNC level does not lead to a high PM2.5, and vice versa, and the need to establish regulatory approaches and control measures to address the impacts of elevated UFP concentrations, especially in urban areas, considering their potential health risks.
100 citations
TL;DR: In this paper, a measurement campaign by a mobile laboratory van was performed in urban microenvironments bounded by a busy street Mannerheimintie in the city center of Helsinki, Finland.
100 citations
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TL;DR: A copy of the Guangbo jiemu bao [Broadcast Program Report] was being passed from hand to hand among a group of young people eager to be the first to read the article introducing the program "What Is Revolutionary Love?".
Abstract: A copy of Guangbo jiemu bao [Broadcast Program Report] was being passed from hand to hand among a group of young people eager to be the first to read the article introducing the program "What Is Revolutionary Love?" It said: "… Young friends, you are certainly very concerned about this problem'. So, we would like you to meet the young women workers Meng Xiaoyu and Meng Yamei and the older cadre Miss Feng. They are the three leading characters in the short story ‘The Place of Love.’ Through the description of the love lives of these three, the story induces us to think deeply about two questions that merit further examination.
1,528 citations
TL;DR: Chapman and Miller as mentioned in this paper, Subset Selection in Regression (Monographs on Statistics and Applied Probability, no. 40, 1990) and Section 5.8.
Abstract: 8. Subset Selection in Regression (Monographs on Statistics and Applied Probability, no. 40). By A. J. Miller. ISBN 0 412 35380 6. Chapman and Hall, London, 1990. 240 pp. £25.00.
1,154 citations
01 Dec 2006
TL;DR: This paper showed that reactive anthropogenic VOCs (AVOCs) produce much larger amounts of SOA than these models predict, even shortly after sunrise, and a significant fraction of the excess SOA is formed from first-generation AVOC oxidation products.
Abstract: [1] The atmospheric chemistry of volatile organic compounds (VOCs) in urban areas results in the formation of ‘photochemical smog’, including secondary organic aerosol (SOA). State-of-the-art SOA models parameterize the results of simulation chamber experiments that bracket the conditions found in the polluted urban atmosphere. Here we show that in the real urban atmosphere reactive anthropogenic VOCs (AVOCs) produce much larger amounts of SOA than these models predict, even shortly after sunrise. Contrary to current belief, a significant fraction of the excess SOA is formed from first-generation AVOC oxidation products. Global models deem AVOCs a very minor contributor to SOA compared to biogenic VOCs (BVOCs). If our results are extrapolated to other urban areas, AVOCs could be responsible for additional 3–25 Tg yr−1 SOA production globally, and cause up to −0.1 W m−2 additional top-of-the-atmosphere radiative cooling.
947 citations
TL;DR: The aim of this work was to comprehensively review most of the studies published on this topic in China, including literature concerning field measurements, laboratory studies and the impacts of BB indoors and outdoors in China to provide a basis for formulation of policies and regulations by policy makers in China.
772 citations
University of Leicester1, Earth System Research Laboratory2, Centre national de la recherche scientifique3, Cooperative Institute for Research in Environmental Sciences4, Norwegian Institute for Air Research5, United Kingdom Department for Environment, Food and Rural Affairs6, Japan Agency for Marine-Earth Science and Technology7, International Institute for Applied Systems Analysis8, Danish Meteorological Institute9, Paul Scherrer Institute10, ETH Zurich11, University of California, Irvine12, University of Leeds13, Aristotle University of Thessaloniki14, École Polytechnique Fédérale de Lausanne15, Geophysical Fluid Dynamics Laboratory16, National Center for Atmospheric Research17, Stockholm University18, Swiss Federal Laboratories for Materials Science and Technology19, Forschungszentrum Jülich20, University of Oslo21, Max Planck Society22, University of Helsinki23, Joseph Fourier University24, Blaise Pascal University25, University of York26, University of Toulouse27, University of Urbino28, University of Manchester29, National University of Ireland, Galway30, University of Edinburgh31, Heidelberg University32, University of East Anglia33, Weizmann Institute of Science34, Norwegian Meteorological Institute35, Chalmers University of Technology36, Energy Research Centre of the Netherlands37, University of Stuttgart38, VU University Amsterdam39
TL;DR: A review of the state of scientific understanding in relation to global and regional air quality is outlined in this article, in terms of emissions, processing and transport of trace gases and aerosols.
760 citations