scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Aerosol formation: atmospheric particles from organic vapours.

04 Apr 2002-Nature (Nature Publishing Group)-Vol. 416, Iss: 6880, pp 497-498
TL;DR: It is shown, to the knowledge for the first time, that these newly formed particles are composed primarily of organic species, such as cis-pinonic acid and pinic acid, produced by oxidation of terpenes in organic vapours released from the canopy.
Abstract: Aerosol particles produced over forested areas may affect climate by acting as nuclei for cloud condensation, but their composition (and hence the chemical species that drive their production) remains an open question. Here we show, to our knowledge for the first time, that these newly formed particles (3–5 nm in diameter) are composed primarily of organic species, such as cis-pinonic acid and pinic acid, produced by oxidation of terpenes in organic vapours released from the canopy1,2,3,4.
Citations
More filters
Journal ArticleDOI
TL;DR: In this article, an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and analytical techniques used to determine the chemical composition of SOA is presented.
Abstract: Secondary organic aerosol (SOA) accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated with SOA formation are complex and varied, and, despite considerable progress in recent years, a quantitative and predictive understanding of SOA formation does not exist and therefore represents a major research challenge in atmospheric science. This review begins with an update on the current state of knowledge on the global SOA budget and is followed by an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and the analytical techniques used to determine the chemical composition of SOA. A survey of recent laboratory, field and modeling studies is also presented. The following topical and emerging issues are highlighted and discussed in detail: molecular characterization of biogenic SOA constituents, condensed phase reactions and oligomerization, the interaction of atmospheric organic components with sulfuric acid, the chemical and photochemical processing of organics in the atmospheric aqueous phase, aerosol formation from real plant emissions, interaction of atmospheric organic components with water, thermodynamics and mixtures in atmospheric models. Finally, the major challenges ahead in laboratory, field and modeling studies of SOA are discussed and recommendations for future research directions are proposed.

3,324 citations

Journal ArticleDOI
TL;DR: In this article, the authors reviewed existing knowledge with regard to organic aerosol (OA) of importance for global climate modelling and defined critical gaps needed to reduce the involved uncertainties, and synthesized the information to provide a continuous analysis of the flow from the emitted material to the atmosphere up to the point of the climate impact of the produced organic aerosols.
Abstract: The present paper reviews existing knowledge with regard to Organic Aerosol (OA) of importance for global climate modelling and defines critical gaps needed to reduce the involved uncertainties. All pieces required for the representation of OA in a global climate model are sketched out with special attention to Secondary Organic Aerosol (SOA): The emission estimates of primary carbonaceous particles and SOA precursor gases are summarized. The up-to-date understanding of the chemical formation and transformation of condensable organic material is outlined. Knowledge on the hygroscopicity of OA and measurements of optical properties of the organic aerosol constituents are summarized. The mechanisms of interactions of OA with clouds and dry and wet removal processes parameterisations in global models are outlined. This information is synthesized to provide a continuous analysis of the flow from the emitted material to the atmosphere up to the point of the climate impact of the produced organic aerosol. The sources of uncertainties at each step of this process are highlighted as areas that require further studies.

2,863 citations

Journal ArticleDOI
TL;DR: In this paper, the formation rate of 3-nm particles is often in the range 0.01-10 cm −3 s −1 in the boundary layer in urban areas and in coastal areas and industrial plumes.

2,028 citations

Journal ArticleDOI
TL;DR: In this paper, the authors discuss the environmental drivers of phenology, and the impacts of climate change on phenology in different biomes, and assess the potential impact on these feedbacks of shifts in phenology driven by climate change.

1,522 citations

Journal ArticleDOI
TL;DR: In this article, the authors discuss the role of chemical composition and particle size in cloud condensation nucleation processes, and the role that the chemical composition plays in the process of cloud droplet and ice nucleation.

1,347 citations


Cites background from "Aerosol formation: atmospheric part..."

  • ...…e.g., freshly nucleated sulfate particles in the ultrafine size class, which may be as small as 2–9 nm (Kerminen et al., 2000; Kulmala et al., 2000; Kerminen, 2001; Gao et al., 2001; O'Dowd et al., 2002; Lihavainen et al., 2003; Maria et al., 2004; Zhang et al., 2004a,b; Kulmala et al., 2007a,b)....

    [...]

References
More filters
Journal ArticleDOI
01 Oct 1998-Nature
TL;DR: In this article, the authors present measurements of gaseous and particulate atmospheric species from a forested area to show that some hydrocarbons emitted by vegetation are photo-oxidized to organic acids (for example, pinonic acids), which condense to form organic aerosols.
Abstract: Aerosol formation in the atmosphere is an important process to understand, in that such particles may act as the cloud condensation nuclei responsible for the ‘cloud–climate’ effect1, and could locally be hazardous to health. The number-concentration of total atmospheric aerosols and cloud condensation nuclei is largely contributed by organic aerosols1. Much of the organic aerosol is formed from atmospheric gas-to-particle conversion, and the common and widespread non-methane hydrocarbons emitted by vegetation have been investigated as possible precursors2. But strong evidence for a quantitative link between biogenic hydrocarbon emission and organic aerosol formation has so far been lacking. Here we present measurements of gaseous and particulate atmospheric species from a forested area to show that some hydrocarbons (for example, terpenes) emitted by vegetation are photo-oxidized to organic acids (for example, pinonic acids), which condense to form organic aerosols. Thus the forests, through their production of large quantities of organic aerosols, could be of considerable significance both for climate (through cloud-condensation-nuclei formation) and for heterogeneous atmospheric chemical processes.

472 citations

Journal ArticleDOI
TL;DR: In this article, the number size distribution of ambient submicron and ultrafine aerosol particles have been measured on a continuous basis (every 10 minutes) for three quarters of the year 1996, at a forest site in Southern Finland.
Abstract: Number size distribution of ambient submicron and ultrafine aerosol particles have been measured on a continuous basis (every 10 minutes) for three quarters of the year 1996, at a forest site in Southern Finland. Continuous monitoring offers additional insight over the diurnal dynamics of the submicron size distribution, including existence of clearly separate size modes as well as events of new particle formation. Selected examples of the measured size distributions are presented, including the particle formation events observed at the measurement site. Typical characteristics of days with particle formation events versus days of no events are discussed.

381 citations

Journal ArticleDOI
01 Sep 2001-Tellus B
TL;DR: In this article, the authors investigated the formation mechanisms of aerosol particles in the boreal forest site and quantified the amount of condensable vapours produced in photochemical reactions of biogenic volatile organic compounds (BVOC) leading to aerosol formation.
Abstract: Aerosol formation and subsequent particle growth in ambient air have been frequently observed at a boreal forest site (SMEAR II station) in Southern Finland. The EU funded project BIOFOR (Biogenic aerosol formation in the boreal forest) has focused on: (a) determination of formation mechanisms of aerosol particles in the boreal forest site; (b) verification of emissions of secondary organic aerosols from the boreal forest site; and (c) quantification of the amount of condensable vapours produced in photochemical reactions of biogenic volatile organic compounds (BVOC) leading to aerosol formation. The approach of the project was to combine the continuous measurements with a number of intensive field studies. These field studies were organised in three periods, two of which were during the most intense particle production season and one during a non-event season. Although the exact formation route for 3 nm particles remains unclear, the results can be summarised as follows: Nucleation was always connected to Arctic or Polar air advecting over the site, giving conditions for a stable nocturnal boundary layer followed by a rapid formation and growth of a turbulent convective mixed layer closely followed by formation of new particles. The nucleation seems to occur in the mixed layer or entrainment zone. However two more prerequisites seem to be necessary. A certain threshold of high enough sulphuric acid and ammonia concentrations is probably needed as the number of newly formed particles was correlated with the product of the sulphuric acid production and the ammonia concentrations. No such correlation was found with the oxidation products of terpenes. The condensation sink, i.e., effective particle area, is probably of importance as no nucleation was observed at high values of the condensation sink. From measurement of the hygroscopic properties of the nucleation particles it was found that inorganic compounds and hygroscopic organic compounds contributed both to the particle growth during daytime while at night time organic compounds dominated. Emissions rates for several gaseous compounds was determined. Using four independent ways to estimate the amount of the condensable vapour needed for observed growth of aerosol particles we get an estimate of 2–10×10 7 vapour molecules cm −3 . The estimations for source rate give 7.5–11×10 4 cm −3 s −1 . These results lead to the following conclusions: The most probable formation mechanism is ternary nucleation (water-sulphuric acid-ammonia). After nucleation, growth into observable sizes (∼3 nm) is required before new particles appear. The major part of this growth is probably due to condensation of organic vapours. However, there is lack of direct proof of this phenomenon because the composition of 1–5 nm size particles is extremely difficult to determine using the present state-of-art instrumentation DOI: 10.1034/j.1600-0889.2001.530402.x

349 citations

Journal ArticleDOI
TL;DR: A case study from July 7-8 provides evidence of nucleation and condensation of products related to the oxidation of different biogenic emissions at Kejimkujik National Park, Canada.
Abstract: Aerosol and trace gas measurements were made at Kejimkujik National Park, Nova Scotia, Canada, during the summer of 1996. A case study from July 7-8 provides evidence of nucleation and condensation of products related to the oxidation of different biogenic emissions. Particles from 5 nm to 50 nm in diameter evolved during the afternoon and early evening associated with variations in isoprene. Late in the evening the α- and β-pinene mixing ratios and the aerosol particle volume increased. Soon after, there was a sharp increase in RO 2 H/H 2 O 2 that persisted until about 0100 LT. The initial increases in the pinenes and aerosols were strong and influenced by changes in winds. After 2200 LT, and into the early morning, the winds were relatively steady, and the α-and β-pinene mixing ratios continually decreased. The decay of α-pinene is explained through reaction with O 3 . However, the addition of OH radicals from the reaction of terpenes with O 3 is necessary to explain the observed rate of decay of β-pinene. During the same time, the aerosol volume increased with the decrease in α- and β-pinene. The volume increase was distributed 40:60 between particles in a mode centered at 80-90 nm and particles > 150 nm. The fine particle mass concentrations of the measured inorganic ions (sulfate, nitrate, chloride, ammonium, sodium, and calcium) and organic ions (oxalate, formate, acetate, pyruvate, propionate) account for 25-30% of the total aerosol volume during the period (2.7 μm 3 cm -3 ) indicating that the aerosol volume increase was due to unidentified species. Assuming that the increase in the aerosol was the result of products from the oxidation of α- and β-pinene, an aerosol mass yield of 13% is estimated. The concentrations of cloud condensation nuclei active at 0.2% supersaturation were enhanced by the appearance of the 80-90 nm mode pointing to at least some of these forest-generated particles as being able to serve as nuclei for cloud droplets at common atmospheric supersaturations.

92 citations

Journal ArticleDOI
TL;DR: In this paper, an event of new particle formation is presented, based on simultaneous measurements of aerosol number size distributions, relevant gaseous components including H2SO4 and OH, and meteorological parameters.
Abstract: An event of new particle formation is presented, based on simultaneous measurements of aerosol number size distributions, relevant gaseous components including H2SO4 and OH, and meteorological parameters. Measurements were conducted at Hohenpeissenberg, a rural continental mountain site in southern Germany. The event was observed under intense solar radiation, with total particle number concentrations increasing from 6000 to 25000 cm−3 within one hour, and ultrafine particles (3–11 nm) accounting for more than 50% of total number. Observed OH and H2SO4 concentrations reached maximum levels around 107 cm−3. A lower limit of the particle nucleation rate was estimated to be 3 cm−3·s−1, consistent with present models of ternary nucleation involving the H2SO4-H2O-NH3 system. Roughly 80% of the subsequent drop in ultrafine mode particle number concentration could be explained by coagulation. The observed particle growth rate of 2.1±0.1 nm/h was largely attributed to the condensation of measured H2SO4, assuming neutralization by ammonia.

84 citations