Four years of highly time resolved measurements of elemental
and organic carbon at a rural background site in Central Europe

J 2018

Four years of highly time resolved measurements of elemental and organic carbon at a rural background site in Central Europe

MBENGUE, Saliou, Michal FUSEK, Jaroslav SCHWARZ, Petr VODICKA, Adela SMEJKALOVA HOLUBOVA et. al.

Basic information

Original name

Four years of highly time resolved measurements of elemental and organic carbon at a rural background site in Central Europe

Authors

MBENGUE, Saliou (203 Czech Republic), Michal FUSEK (203 Czech Republic), Jaroslav SCHWARZ (203 Czech Republic), Petr VODICKA (203 Czech Republic), Adela SMEJKALOVA HOLUBOVA (203 Czech Republic) and Ivan HOLOUBEK (203 Czech Republic, guarantor, belonging to the institution)

Edition

Atmospheric Environment, OXFORD (ENGLAND), Pergamon Press, 2018, 1352-2310

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10511 Environmental sciences

Country of publisher

United Kingdom of Great Britain and Northern Ireland

Confidentiality degree

není předmětem státního či obchodního tajemství

References:

URL

Impact factor

Impact factor: 4.012

RIV identification code

RIV/00216224:14310/18:00106132

Organization unit

Faculty of Science

DOI

http://dx.doi.org/10.1016/j.atrnosenv.2018.03.056

UT WoS

000432104700032

Keywords in English

Elemental - organic carbon; OC/EC ratio; Variability; Air masses origin; Rural background site; Censored data

Abstract

V originále

Elemental carbon (EC) and organic carbon (OC) in fine atmospheric aerosols (PM2.3: aerodynamic diameter smaller than 2.5 mu m) have been measured with a semi -automatic instrument during a 4 -year survey at the National Atmospheric Observatory Koletice (NAOK), Czech Republic. Ground based measurements were performed from March 2013 to December 2016 with a field Semi -Continuous OCEC Aerosol Analyzer (Sunset Laboratory Inc., USA). The variation of EC and OC concentrations and the OC/EC ratio was characterized for different seasons and days of the week. During our survey, higher concentrations of EC and OC were observed in winter (0.83 +/- 0.67 and 3.33 2.28 mu m(-3), respectively), and lower concentrations were recorded in summer (0.34 +/- 0.18 and 2.30 +/- 1.15 mu g m(-3), respectively). Inversely, the OC/EC ratio with mean value (5.1 +/- 2.6) characteristic to rural background area was higher in summer (7.33 +/- 3.23) in comparison to the other seasons. Since the data contain values below detection and quantification limits of the measuring device (i.e., censored values), statistical methods for censored data have been used in order to compare mean EC and OC concentrations between various seasons. It was found out that there is a significant difference between summer and the other seasons with the exception of mean OC concentrations at noon. In most cases, there was also a significant difference between winter and the other seasons. Moreover, it was found out that when dealing with OC concentrations, it is possible to replace censored values by a constant and still obtain reasonable results. In case of EC concentrations, the method based on censored distributions should be preferred when the sample size is small and the proportion of censored values is high. The diurnal variation of EC and OC is less pronounced in summer. During working days, the EC diurnal pattern displays a morning (between 6:00 and 10:00) and an afternoon/evening (between 18:00 and 22:00) peaks, while for OC, only the afternoon/evening peak is observed. These seasonal, diurnal and weekly variations of EC and OC concentrations and OC/EC ratio are probably related to variability in terms of emission sources (residential heating, traffic), transport characteristic and meteorological conditions. A weaker correlation between EC and OC in summer (r = 0.56) suggests additional sources and/or transport processes during other seasons. The elevated OC/EC ratio, the higher correlation between OC and 03, and the temperature and solar radiation during summer confirmed an increasing contribution of OC from secondary organic carbon (SOC) estimated as at least 59 +/- 11% of total carbon in the PM2.5 using the EC tracer method. Backward trajectories of air masses arriving at 100 m AGL calculated in winter and summer show that higher pollution episodes of EC and OC are predominantly associated with continental air masses confined over Central Europe (about 79%), while lower EC and OC levels are mainly associated with episodes of long-range transport of marine air masses. Interestingly, the results reveal that in winter pollutants emitted during workdays could be accumulated above the region and influence the rural background air quality during some prolonged time of the weekend, especially on Saturday.

Links

CZ.02.1.01/0.0/0.0/16_013/0001315, interní kód MU

Name: ACTRIS - CZ - RI (Acronym: ACTRIS-CZ RI)

Investor: Ministry of Education, Youth and Sports of the CR, Priority axis 1: Strengthening capacities for high-quality research

LM2015037, research and development project

Name: ACTRIS – účast České republiky (Acronym: ACTRIS-CZ)

Investor: Ministry of Education, Youth and Sports of the CR

Citovat

MBENGUE, Saliou, Michal FUSEK, Jaroslav SCHWARZ, Petr VODICKA, Adela SMEJKALOVA HOLUBOVA and Ivan HOLOUBEK. Four years of highly time resolved measurements of elemental and organic carbon at a rural background site in Central Europe. Atmospheric Environment. OXFORD (ENGLAND): Pergamon Press, 2018, vol. 182, June, p. 335-346. ISSN 1352-2310. Available from: https://dx.doi.org/10.1016/j.atrnosenv.2018.03.056.

@article{1495404,
   author = {Mbengue, Saliou and Fusek, Michal and Schwarz, Jaroslav and Vodicka, Petr and Smejkalova Holubova, Adela and Holoubek, Ivan},
   article_location = {OXFORD (ENGLAND)},
   article_number = {June},
   doi = {http://dx.doi.org/10.1016/j.atrnosenv.2018.03.056},
   keywords = {Elemental - organic carbon; OC/EC ratio; Variability; Air masses origin; Rural background site; Censored data},
   language = {eng},
   issn = {1352-2310},
   journal = {Atmospheric Environment},
   title = {Four years of highly time resolved measurements of elemental and organic carbon at a rural background site in Central Europe},
   url = {https://www.sciencedirect.com/science/article/pii/S1352231018302188?via%3Dihub},
   volume = {182},
   year = {2018}
}

TY  - JOUR
ID  - 1495404
AU  - Mbengue, Saliou - Fusek, Michal - Schwarz, Jaroslav - Vodicka, Petr - Smejkalova Holubova, Adela - Holoubek, Ivan
PY  - 2018
TI  - Four years of highly time resolved measurements of elemental and organic carbon at a rural background site in Central Europe
JF  - Atmospheric Environment
VL  - 182
IS  - June
SP  - 335-346
EP  - 335-346
PB  - Pergamon Press
SN  - 13522310
KW  - Elemental - organic carbon
KW  - OC/EC ratio
KW  - Variability
KW  - Air masses origin
KW  - Rural background site
KW  - Censored data
UR  - https://www.sciencedirect.com/science/article/pii/S1352231018302188?via%3Dihub
L2  - https://www.sciencedirect.com/science/article/pii/S1352231018302188?via%3Dihub
N2  - Elemental carbon (EC) and organic carbon (OC) in fine atmospheric aerosols (PM2.3: aerodynamic diameter smaller than 2.5 mu m) have been measured with a semi -automatic instrument during a 4 -year survey at the National Atmospheric Observatory Koletice (NAOK), Czech Republic. Ground based measurements were performed from March 2013 to December 2016 with a field Semi -Continuous OCEC Aerosol Analyzer (Sunset Laboratory Inc., USA). The variation of EC and OC concentrations and the OC/EC ratio was characterized for different seasons and days of the week. During our survey, higher concentrations of EC and OC were observed in winter (0.83 +/- 0.67 and 3.33 2.28 mu m(-3), respectively), and lower concentrations were recorded in summer (0.34 +/- 0.18 and 2.30 +/- 1.15 mu g m(-3), respectively). Inversely, the OC/EC ratio with mean value (5.1 +/- 2.6) characteristic to rural background area was higher in summer (7.33 +/- 3.23) in comparison to the other seasons. Since the data contain values below detection and quantification limits of the measuring device (i.e., censored values), statistical methods for censored data have been used in order to compare mean EC and OC concentrations between various seasons. It was found out that there is a significant difference between summer and the other seasons with the exception of mean OC concentrations at noon. In most cases, there was also a significant difference between winter and the other seasons. Moreover, it was found out that when dealing with OC concentrations, it is possible to replace censored values by a constant and still obtain reasonable results. In case of EC concentrations, the method based on censored distributions should be preferred when the sample size is small and the proportion of censored values is high. The diurnal variation of EC and OC is less pronounced in summer. During working days, the EC diurnal pattern displays a morning (between 6:00 and 10:00) and an afternoon/evening (between 18:00 and 22:00) peaks, while for OC, only the afternoon/evening peak is observed. These seasonal, diurnal and weekly variations of EC and OC concentrations and OC/EC ratio are probably related to variability in terms of emission sources (residential heating, traffic), transport characteristic and meteorological conditions. A weaker correlation between EC and OC in summer (r = 0.56) suggests additional sources and/or transport processes during other seasons. The elevated OC/EC ratio, the higher correlation between OC and 03, and the temperature and solar radiation during summer confirmed an increasing contribution of OC from secondary organic carbon (SOC) estimated as at least 59 +/- 11% of total carbon in the PM2.5 using the EC tracer method. Backward trajectories of air masses arriving at 100 m AGL calculated in winter and summer show that higher pollution episodes of EC and OC are predominantly associated with continental air masses confined over Central Europe (about 79%), while lower EC and OC levels are mainly associated with episodes of long-range transport of marine air masses. Interestingly, the results reveal that in winter pollutants emitted during workdays could be accumulated above the region and influence the rural background air quality during some prolonged time of the weekend, especially on Saturday.
ER  -

MBENGUE, Saliou, Michal FUSEK, Jaroslav SCHWARZ, Petr VODICKA, Adela SMEJKALOVA HOLUBOVA and Ivan HOLOUBEK. Four years of highly time resolved measurements of elemental and organic carbon at a rural background site in Central Europe. \textit{Atmospheric Environment}. OXFORD (ENGLAND): Pergamon Press, 2018, vol.~182, June, p.~335-346. ISSN~1352-2310. Available from: https://dx.doi.org/10.1016/j.atrnosenv.2018.03.056.

Detailed Information on Publication Record