The association between PM_(2.5)(particulate matter≤2.5μm)short-term exposure and its health effect is non-linear from the epidemiological studies.And this nonlinearity is suggested to be related with the PM_(2.5)he...The association between PM_(2.5)(particulate matter≤2.5μm)short-term exposure and its health effect is non-linear from the epidemiological studies.And this nonlinearity is suggested to be related with the PM_(2.5)heterogeneity,however,the underlying biological mechanism is still unclear.Here,a total of 38 PM_(2.5)filters were collected continuously for three weeks in winter Beijing,with the ambient PM_(2.5)varying between 10 and 270μg/m^(3).Human monocytes-derived macrophages(THP-1)were treated with PM_(2.5)water-soluble elutes at10μg/mL to investigate the PM_(2.5)short-term exposure effect from a proinflammatory perspective.The proinflammatory cytokine tumor necrosis factor(TNF)induced by the PM_(2.5)elutes at equal concentrations were unequal,showing the heterogeneity of PM_(2.5)proinflammatory potentials.Of the various chemical and biological components,lipopolysaccharide(LPS)showed a strong positive association with the TNF heterogeneity.However,some outliers were observed among the TNF-LPS association.Specifically,for PM_(2.5)from relatively clean air episodes,the higher LPS amount corresponded to relatively low TNF levels.And this phenomenon was also observed in the promotion tests by treating macrophages with PM_(2.5)elutes dosed with additional trace LPS.Gene expression analysis indicated the involvement of oxidative-stress related genes in the LPS signaling pathway.Therefore,a potential oxidative-stress-mediated suppression on the PM_(2.5)-borne LPS proinflammatory effect was proposed to be accounted for the outliers.Overall,the results showed the differential role of LPS in the heterogeneity of PM_(2.5)proinflammatory effects from a component-based perspective.Future experimental studies are needed to elucidate the signaling pathway of LPS attached on PM_(2.5)from different air quality episodes.展开更多
Nighttime aqueous oxidation of fossil fuel emissions is a significant source of atmospheric secondary organic aerosols.However,the underlying mechanism of the aqueous processing remains unclear.Utilizing ultrahigh-res...Nighttime aqueous oxidation of fossil fuel emissions is a significant source of atmospheric secondary organic aerosols.However,the underlying mechanism of the aqueous processing remains unclear.Utilizing ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry of watersoluble organic carbon samples,we present field observations that reveal the aqueous-phase conversion of nitroaromatic compounds(NACs)and sulfur-containing aerosols from fossil fuel combustion at high relative humidity during a severe haze event in Beijing in the winter of 2016.We have confirmed that the ring-breaking oxidation of NACs can generate nitrous acid in the aqueous phase,which rapidly oxidizes sulfur dioxide(SO_(2))to sulfate.Subsequently,reactions between sulfate and unsaturated compounds contribute to the formation of aliphatic organosulfates.Our results elucidate a molecular-level understanding of the aqueous production of sulfur-containing aerosols from NACs and SO_(2) in wintertime urban haze.展开更多
基金supported by the National Natural Science Foundation of China (Nos.42075117 and 41807306)。
文摘The association between PM_(2.5)(particulate matter≤2.5μm)short-term exposure and its health effect is non-linear from the epidemiological studies.And this nonlinearity is suggested to be related with the PM_(2.5)heterogeneity,however,the underlying biological mechanism is still unclear.Here,a total of 38 PM_(2.5)filters were collected continuously for three weeks in winter Beijing,with the ambient PM_(2.5)varying between 10 and 270μg/m^(3).Human monocytes-derived macrophages(THP-1)were treated with PM_(2.5)water-soluble elutes at10μg/mL to investigate the PM_(2.5)short-term exposure effect from a proinflammatory perspective.The proinflammatory cytokine tumor necrosis factor(TNF)induced by the PM_(2.5)elutes at equal concentrations were unequal,showing the heterogeneity of PM_(2.5)proinflammatory potentials.Of the various chemical and biological components,lipopolysaccharide(LPS)showed a strong positive association with the TNF heterogeneity.However,some outliers were observed among the TNF-LPS association.Specifically,for PM_(2.5)from relatively clean air episodes,the higher LPS amount corresponded to relatively low TNF levels.And this phenomenon was also observed in the promotion tests by treating macrophages with PM_(2.5)elutes dosed with additional trace LPS.Gene expression analysis indicated the involvement of oxidative-stress related genes in the LPS signaling pathway.Therefore,a potential oxidative-stress-mediated suppression on the PM_(2.5)-borne LPS proinflammatory effect was proposed to be accounted for the outliers.Overall,the results showed the differential role of LPS in the heterogeneity of PM_(2.5)proinflammatory effects from a component-based perspective.Future experimental studies are needed to elucidate the signaling pathway of LPS attached on PM_(2.5)from different air quality episodes.
基金supported by the National Natural Science Foundation of China(42130513,42221001,22276099,and U24A20515)the Harvard-NUIST Joint Laboratory on Air Quality and Climate(JLAQC)。
文摘Nighttime aqueous oxidation of fossil fuel emissions is a significant source of atmospheric secondary organic aerosols.However,the underlying mechanism of the aqueous processing remains unclear.Utilizing ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry of watersoluble organic carbon samples,we present field observations that reveal the aqueous-phase conversion of nitroaromatic compounds(NACs)and sulfur-containing aerosols from fossil fuel combustion at high relative humidity during a severe haze event in Beijing in the winter of 2016.We have confirmed that the ring-breaking oxidation of NACs can generate nitrous acid in the aqueous phase,which rapidly oxidizes sulfur dioxide(SO_(2))to sulfate.Subsequently,reactions between sulfate and unsaturated compounds contribute to the formation of aliphatic organosulfates.Our results elucidate a molecular-level understanding of the aqueous production of sulfur-containing aerosols from NACs and SO_(2) in wintertime urban haze.
