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Secondary organic aerosol (SOA) formation is important in the field of atmospheric science due to its impacts on public health and climate change. However, the molecular compositions or formation mechanisms of SOA have not been fully characterized in ambient atmospheres. In this study, ambient fine particle (PM 2.5) samples were collected in two urban cities in Beijing, China and Gwangju, Korea during the winter and summer seasons, and the SOA-associated molecular features were characterized by using Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). We found that the secondary organic carbon (SOC) during wintertime in Gwangju exhibit a more aliphatic nature, and those in Beijing have more aromatic structures like humic compounds. The contribution of CHOS to the total identified WSOC associated SOC was the most abundant at Beijing site (∼40%) compared to the Gwangju site (∼30%), and the proportion of CHON species in the WSOC associated SOC accounted for ∼30% in Beijing and 20–30% in Gwangju. Majority of SOC-derived CHOS species (∼99%) likely contained sulfate functional groups at both sites regardless of the sampling season. Organonitrates predominated in CHON species in summer compared to winter, but some fractions appeared to contain other potential nitrogen functional groups such as amide and nitrile (∼20%), suggesting the existence of other formation pathways of organic nitrogen, especially during winter. This work gave an observation insight into the molecular features of SOC at two different sites, and will deepen the understanding on the region-specific SOA formation mechanisms. [Display omitted] • A total of 10,790 chemical formulas assigned from PM 2.5 -drived WSOC samples. • SOC fractions were discriminated from the WSOC compositions. • SOC compounds during winter in Gwangju exhibit a more aliphatic nature than in Beijing. • Gwangju exhibit a more favorable environment for SOA formation process than Beijing. [ABSTRACT FROM AUTHOR]

Recently evidence linking the effects of fine-dust (FD) on skin inflammation is exaggerating. Fucoidan derived from brown algae has great potential for ameliorating oxidative stress and inflammation. Herein, a fucoidan fraction (SHC4-6) was purified from an enzymatic (Celluclast) extract of an invasive seaweed, Sargassum horneri following gradient ethanol precipitation and anion exchange chromatography. Effectiveness of SHC4-6 in ameliorating FD (from Beijing, China)-induced inflammatory responses in HaCaT keratinocytes and recovery of skin barrier dysfunction was evaluated. SHC4-6 was comprising of sulfated mannofucans with their molecular weights distributed around 45 kDa. SHC4-6 dose-dependently lowered ROS levels in FD-induced HaCaT keratinocytes, ameliorating viability at 50 μg mL−1. SHC4–6 downregulated inflammatory cytokines, tumor necrosis factor-α, interleukin (IL)-1β, -5, -6, -8, -13, interferon-γ, and chemokines, macrophage-derived chemokine, eotaxin, and thymus and activation regulated chemokine by inhibiting mitogen-activated protein kinase and nuclear factor-κB pathways. SHC4–6 treatment ameliorated key tight junction proteins and skin hydration factors, depicting the effects of fucoidan in reducing FD-induced inflammation and skin barrier deterioration. With further studies in place, SHC4-6 could be used as an ingredient for developing cosmetics to relieve FD-induced skin inflammation. • Isolation of low molecular weight fucoidan from Sargassum horneri was described. • Selected fucoidan, SHC4-6, was treated on fine dust-induced human keratinocytes. • SHC4-6 indicated protective effects via lowering inflammatory responses and defective skin barrio functions. • NF-κB and MAPK pathways might involve in the SHC4-6 mediated anti-inflammatory effects. [ABSTRACT FROM AUTHOR]

Abstract: Previously, we demonstrated that the concentrations of DDTs were greater in breast milk collected from Chinese mothers than from Japanese and Korean mothers. To investigate dicofol as a possible source of the DDTs in human breast milk, we collected breast milk samples from 2007 to 2009 in China (Beijing), Korea (Seoul, Busan) and Japan (Sendai, Takarazuka and Takayama). Using these breast milk samples, we quantified the concentrations of dichlorobenzophenone, a pyrolysis product of dicofol (simply referred to as dicofol hereafter), dichlorodiphenyltrichloroethane and its metabolites (DDTs) using GC–MS. Overall, 12 of 14 pooled breast milk samples from 210 mothers contained detectable levels of dicofol (>0.1ngg−1 lipid). The geometric mean concentration of dicofol in the Japanese breast milk samples was 0.3ngg−1 lipid and significantly lower than that in Chinese (9.6ngg−1 lipid) or Korean breast milk samples (1.9ngg−1 lipid) (p <0.05 for each). Furthermore, the ΣDDT levels in breast milk from China were 10-fold higher than those from Korea and Japan. The present results strongly suggest the presence of extensive emission sources of both dicofol and DDTs in China. However, exposure to dicofol cannot explain the large exposure of Chinese mothers to DDTs because of the trace levels of dicofol in the ΣDDTs. In the present study, dicofol was confirmed to be detectable in human breast milk. This is the first report to identify dicofol in human samples. [ABSTRACT FROM AUTHOR]

Abstract: Human breast milk samples collected in 2007–2008 from four countries, Vietnam (Hanoi), China (Beijing), Korea (Seoul) and Japan (Sendai, Kyoto and Takayama), were analyzed for persistent organic pollutants (POPs) such as dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane-related compounds (CHLs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Comparing with previous surveys, the present study indicates that the DDTs in breast milk from China and Vietnam had gradually decreased during the last decade, but were still 5–10 times higher than those in other nations. The ratios of p,p′-DDE/p,p′-DDT and o,p′-DDT/p,p′-DDT were higher in Beijing than in the other countries, suggesting that there is less fresh intake of commercial DDT products and a possible exposure to dicofol in China. CHL and PCB levels were relatively higher in mothers from Japan, whereas β-HCH and HCB were more common in Chinese women. In Japan, it is suspected that mothers in the urban/coastal area (Sendai) were more continuously exposed to organochlorine pesticides (OCPs) than mothers in the rural/inland area (Takayama). In addition, OCP levels in primiparae were significantly higher than those in multiparae from Japan and Korea. These indicate that both parity and regional factors are major determinants of the levels of OCPs and PCBs in human milk. On the other hand, higher concentrations of PBDEs were observed in mothers'' milk from Korea. The congener was dominated by BDE-47 (43–54%), followed by BDE-153 (23–33%) in all regions except for Beijing where BDE-28 (23%) was relatively abundant. In Japanese breast milk, regional and parity-dependent distributions were not observed for PBDEs. Among PBDE congeners, age-dependency was observed for BDE-153, which was negatively correlated (p <0.05) to the age of mothers in Kyoto (17 participants were housewives), while it increased with age in Sendai (10 participants were clerks). No such correlation was seen for BDE-47, indicating that BDE-47 was ingested and assimilated via different kinetics or routes from BDE-153 in Japan. [Copyright &y& Elsevier]