Aerosols

Hatakeyama, Shiro

doi:10.1007/978-4-431-56438-6_2

Cited by 4 publications

(2 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Coarse-mode particles are related to primary emissions like industrial activities and biomass burning. This type of particle is highly correlated with the change of mass concentration [18,19]. Fine-mode particles are mainly considered as secondary aerosols formed by gaseous precursors, oxidants, and/or changes of meteorological conditions [20][21][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Long-Term Variation Study of Fine-Mode Particle Size and Regional Characteristics Using AERONET Data

et al. 2022

View full text Add to dashboard Cite

To identify the long-term trend of particle size variation, we analyzed aerosol optical depth (AOD, τ) separated as dust (τD) and coarse-(τPC) and fine-pollution particles (τPF) depending on emission sources and size. Ångström exponent values are also identified separately as total and fine-mode particles (αT and αPF). We checked these trends in various ways; (1) first-order linear regression analysis of the annual average values, (2) percent variation using the slope of linear regression method, and (3) a reliability analysis using the Mann–Kendall (MK) test. We selected 17 AERONET sun/sky radiometer sites classified into six regions, i.e., Europe, North Africa, the Middle East, India, Southeast Asia, and Northeast Asia. Although there were regional differences, τ decreased in Europe and Asian regions and increased in the Middle East, India, and North Africa. Values of τPC and τPF, show that aerosol loading caused by non-dust aerosols decreased in Europe and Asia and increased in India. In particular, τPF considerably decreased in Europe and Northeast Asia (95% confidential levels in MK-test), and τPC decreased in Northeast Asia (Z-values for Seoul and Osaka are −2.955 and −2.306, respectively, statistically significant if |z| ≥ 1.96). The decrease in τPC seems to be because of the reduction of primary and anthropogenic emissions from regulation by air quality policies. The meaningful result in this paper is that the particle size became smaller, as seen by values of αT that decreased by −3.30 to −30.47% in Europe, North Africa, and the Middle East because αT provides information on the particle size. Particle size on average became smaller over India and Asian regions considered in our study due to the decrease in coarse particles. In particular, an increase of αPF in most areas shows the probability that the average particle size of fine-mode aerosols became smaller in recent years. We presumed the cause of the increase in αT is because relatively large-sized fine-mode particles were eliminated due to air quality policies.

show abstract

Section: Introductionmentioning

confidence: 99%

Long-Term Variation Study of Fine-Mode Particle Size and Regional Characteristics Using AERONET Data

et al. 2022

View full text Add to dashboard Cite

show abstract

“…We focused on Japanese larch (Larix kaempferi), a deciduous conifer, and Sakhalin fir (Abies sachalinensis), an evergreen conifer, because the species are ecologically and economically important in northern Japan (Kita et al 2009, Goto et al 2011, where O3 tends to be elevated from spring to early summer (Koike et al 2013, Hatakeyama 2017. Japanese larch is a light-demanding pioneer species and has a high photosynthetic capacity (Ryu et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Can needle nitrogen content explain the interspecific difference in ozone sensitivities of photosynthesis between Japanese larch (Larix kaempferi) and Sakhalin fir (Abies sachalinensis)?

Sugai¹,

Kitao²,

Koike³

2019

Photosynt.

View full text Add to dashboard Cite

Although deciduous and evergreen conifers are expected to utilize needle nitrogen differently, their interspecific differences in the ozone sensitivity remain unclear. We compared the growth and physiological responses to elevated O3 concentrations in deciduous Japanese larch (Larix kaempferi) and evergreen Sakhalin fir (Abies sachalinensis) seedlings. Seedlings of both species were exposed to 62.5 ± 1.95 nmol(O3) mol-1 during the day time in open-top chambers. Elevated O3 had no effect on height or diameter growth in either of the species but suppressed photosynthetic parameters. A decline in photosynthetic nitrogen-use efficiency was observed in both species. However, needle N content in larch was decreased by O3, whereas it was not decreased in fir. Needle N responses to O3 were different between larch and fir seedlings, indicating that the O3 sensitivity of photosynthesis could vary depending on needle N dynamics. We also observed a higher correlation between photosynthesis and needle N even under O3 exposure, particularly in the mass-based relationship with higher accuracy. The result indicated that mass-based needle N could explain difference in O3 sensitivity of photosynthesis between the different leaf habits in larch and fir seedlings.

show abstract

Leaf defense capacity of Japanese elm (Ulmus davidiana var. japonica) seedlings subjected to a nitrogen loading and insect herbivore dynamics in a free air ozone-enriched environment

Sugai

Okamoto

Agathokleous

et al. 2019

Environ Sci Pollut Res

View full text Add to dashboard Cite

Japanese elm (Ulmus davidiana var. japonica) is a native species in cool temperate forests in Japan. We investigated growth, physiological reactions, and leaf defense capacity of Japanese elm seedlings under nitrogen (N) loading (45.3 kg N ha -1 yr -1 ) and seasonal insect dynamics in a free-air ozone (O3)-enriched environment (about 54.5 nmol O3 mol -1 ) over a growing season. Higher leaf N content and lower condensed tannin content under N loading and lower condensed tannin content in elevated O3 were observed, suggesting that both N loading and elevated O3 decreased the leaf defense capacity and that N loading further enhanced the leaf quality as food resource of insect herbivores. Two major herbivores were observed on the plants, elm leaf-beetle (Pyrrhalta maculicollis) and elm sawfly (Arge captiva). The peak number of observed insects was decreased by N loading. Visible foliar injury caused by N loading might directly induce the reduction of number of the observed elm sawfly individuals. While elevated O3 slightly suppressed the chemical defense capacity, significantly lower number of elm leaf-beetle was observed in elevated O3. We conclude that N loading and elevated O3 can alter not only the leaf defense capacity of Japanese elm seedlings, but also the dynamics of elm leaf-beetle and sawfly herbivores.

show abstract

Aerosols

Cited by 4 publications

References 32 publications

Long-Term Variation Study of Fine-Mode Particle Size and Regional Characteristics Using AERONET Data

Long-Term Variation Study of Fine-Mode Particle Size and Regional Characteristics Using AERONET Data

Can needle nitrogen content explain the interspecific difference in ozone sensitivities of photosynthesis between Japanese larch (Larix kaempferi) and Sakhalin fir (Abies sachalinensis)?

Leaf defense capacity of Japanese elm (Ulmus davidiana var. japonica) seedlings subjected to a nitrogen loading and insect herbivore dynamics in a free air ozone-enriched environment

Contact Info

Product

Resources

About