Characterization of hydrocarbons in aerosols and investigation of biogenic sources as a carrier of radiocesium isotopes

Nakagawa, Mayuko; Yamada, Keita; Toyoda, Sakae; Kita, K.; Igarashi, Yasuhito; Komatsu, Shojiro; Yamada, Kentaro; Yoshida, Naohiro

doi:10.2343/geochemj.2.0512

Cited by 9 publications

(6 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Based on recent cumulative knowledge, major resuspension aerosols could be supermicron-sized, such as soil dust (Ishizuka et al, 2017;Kinase et al, 2018) and bioaerosols (Kinase et al, 2018;Igarashi et al, 2019b;Kita et al, 2020;Minami et al, 2020;Igarashi, 2021). Lower possibilities of submicron particle involvement, such as that resulting from forest fires (Kinase et al, 2018) and epicuticular wax (Nakagawa et al, 2018), have been reported. Thus, the regional budget considering supermicron aerosols is significantly different from that considering submicron aerosols: faster supermicron deposition rates necessitated higher emission fluxes to sustain the simulated surface concentrations at the observed levels.…”

Section: Discussionmentioning

confidence: 99%

Reassessment of the radiocesium resuspension flux from contaminated ground surfaces in East Japan

Kajino

Watanabe

Ishizuka

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. Resuspension of 137Cs from the contaminated ground surface to the atmosphere is essential for understanding the environmental behaviors of 137Cs and estimating external and inhalation exposure of residents. Kajino et al. (2016) assessed the 137Cs resuspension flux from bare soil and forest ecosystems in East Japan in 2013 using a numerical simulation constrained by surface air concentration measurements. However, the simulation was found to underestimate the observed deposition amounts by two orders of magnitude. The reason for this underestimation is that the simulation assumed that resuspended 137Cs is carried by submicron aerosols, which have low deposition rates. Based on the observational indications that soil dust and bioaerosols are the major carriers of resuspended 137Cs, a new simulation is performed with higher deposition rates constrained by both surface concentrations and deposition amounts. In the new estimation, the areal total annual resuspension of 137Cs in 2013 is 25.7 TBq, which is equivalent to 0.96 % of the initial deposition (2.68 PBq). Due to the rapid deposition rates, the annual redeposition amount is also large at 10.6 TBq, approximately 40 % of the resuspended 137Cs. The resuspension rate through the atmosphere (0.96 % y−1) seems slow, but it (2.6 × 10−5 d−1) may not be negligibly small compared to the actual decreasing trend of the ambient gamma dose rate obtained in Fukushima Prefecture after the radioactive decay of 137Cs plus 134Cs in 2013 is subtracted (1.0–7.9 × 10−4 d−1): Resuspension can account for 1–10 % of the decreasing rate due to decontamination and natural decay through land surface processes. The current simulation underestimated the 137Cs deposition in Fukushima city in winter by more than an order of magnitude, indicating the presence of additional resuspension sources. The site of Fukushima city is surrounded by major roads. Heavy traffic on wet and muddy roads after snow removal operations could generate superlarge (approximately 100 µm in diameter) road dust or road salt particles, which is not included in the model but might contribute to the observed 137Cs at the site.

show abstract

Section: Discussionmentioning

confidence: 99%

Reassessment of the radiocesium resuspension flux from contaminated ground surfaces in East Japan

Kajino

Watanabe

Ishizuka

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Since K16 was published, several emission sources of resuspended 137 Cs have been indicated, such as soil dust (Ishizuka et al, 2017;Kinase et al, 2018) and bioaerosols (Kinase et al, 2018;Nakagawa et al, 2018;Igarashi et al, 2019b;Kita et al, 2020;Minami et al, 2020;Igarashi, 2021), but the relative contributions of these sources, the spatiotemporal variations in the associated emission fluxes, and their size distributions are still not well understood. Kita et al (2020) indicated the associations of rain with fungal spore emissions, and Minami et al (2020) estimated the emission flux of 137 Cs associated with bioaerosols; however, the emission flux has not yet been formulated as a function of meteorological or land surface variables.…”

Section: Constraint Of Modeled Deposition Parametersmentioning

confidence: 99%

“…Ochiai et al (2016) also showed that the temporal variations in fine-mode (< 1.1 µm in diameter) and coarse-mode (> 1.1 µm) 137 Cs behaved differently by season, indicating that the major emission sources could be different between winter and summer. Nakagawa et al (2018) conducted size-resolved n-alkane and 137 Cs measurements in similar forest areas and concluded that among biogenic emission sources, epicuticular wax is less likely and bioaerosols such as pollen and fungal spores are more likely. Based on long-term measurements taken in the same forest area, Kinase et al (2018) indicated the association of mineral dust in late spring and bioaerosols in summer and autumn.…”

Section: Introductionmentioning

confidence: 99%

Reassessment of the radiocesium resuspension flux from contaminated ground surfaces in eastern Japan

et al. 2022

Self Cite

View full text Add to dashboard Cite

Abstract. Resuspension of 137Cs from the contaminated ground surface to the atmosphere is essential for understanding the environmental behaviors of 137Cs and estimating external and inhalation exposure of residents. Kajino et al. (2016) assessed the 137Cs resuspension flux from bare soil and forest ecosystems in eastern Japan in 2013 using a numerical simulation constrained by surface air concentration measurements. However, the simulation was found to underestimate the observed deposition amounts by 2 orders of magnitude. The reason for this underestimation is that the simulation assumed that resuspended 137Cs is carried by submicron aerosols, which have low deposition rates. Based on the observational indications that soil dust and bioaerosols are the major carriers of resuspended 137Cs, a new simulation is performed with higher deposition rates constrained by both surface concentrations and deposition amounts. In the new estimation, the total areal annual resuspension of 137Cs in 2013 is 25.7 TBq, which is equivalent to 0.96 % of the initial deposition (2.68 PBq). Due to the rapid deposition rates, the annual redeposition amount is also large at 10.6 TBq, approximately 40 % of the resuspended 137Cs. The resuspension rate through the atmosphere (0.96 % yr−1) seems slow, but it (2.6 × 10−5 d−1) may not be negligibly small compared to the actual decreasing trend of the ambient gamma dose rate obtained in Fukushima Prefecture after the radioactive decay of 137Cs plus 134Cs in 2013 is subtracted (1.0–7.9 × 10−4 d−1): resuspension can account for 1 %–10 % of the decreasing rate due to decontamination and natural decay through land surface processes. The current simulation underestimated the 137Cs deposition in Fukushima city in winter by more than an order of magnitude, indicating the presence of additional resuspension sources. The site of Fukushima city is surrounded by major roads. Heavy traffic on wet and muddy roads after snow removal operations could generate superlarge (approximately 100 µm in diameter) road dust or road salt particles, which are not included in the model but might contribute to the observed 137Cs at the site.

show abstract

“…Since K16 was published, several emission sources of resuspended 137 Cs have been indicated, such as soil dust (Ishizuka et al, 2017;Kinase et al, 2018) and bioaerosols (Kinase et al, 2018;Nakagawa et al, 2018;Igarashi et al, 2019b;Kita et al, 2020;Minami et al, 2020;Igarashi, 2021), but the relative contributions of these sources, the spatiotemporal variations in the associated emission fluxes, and their size distributions are still not well understood. 2021) evaluated the performance of the K16 model using concentrations and deposition amounts measured at Fukushima sites and found that the seasonal variations in simulated concentrations were opposite to those observed and that the simulated deposition amounts were underestimated by one to two orders of magnitude.…”

Section: Constraint Of Modeled Deposition Parametersmentioning

confidence: 99%

Reply on RC2

Kajino

2021

View full text Add to dashboard Cite

Characterization of hydrocarbons in aerosols and investigation of biogenic sources as a carrier of radiocesium isotopes

Cited by 9 publications

References 33 publications

Reassessment of the radiocesium resuspension flux from contaminated ground surfaces in East Japan

Reassessment of the radiocesium resuspension flux from contaminated ground surfaces in East Japan

Reassessment of the radiocesium resuspension flux from contaminated ground surfaces in eastern Japan

Reply on RC2

Contact Info

Product

Resources

About