PM_(2.5)pollution variations in different microenvironments would result in PM_(2.5)exposure inequity between rural and urban residents.In this study,the real-time PM_(2.5)exposure of urban and rural residents in Chin...PM_(2.5)pollution variations in different microenvironments would result in PM_(2.5)exposure inequity between rural and urban residents.In this study,the real-time PM_(2.5)exposure of urban and rural residents in China was examined based on portable PM_(2.5)sensors together with activity patterns derived from questionnaire surveys,with a focus on students and senior citizens who are sensitive to air pollution.The results showed that PM_(2.5)exposure varied significantly among different resident groups,with higher PM_(2.5)exposure of rural residents than those of urban residents.PM_(2.5)exposure peaks mostly occurred during(Accompanied)cooking activities owing to strong emissions.Sleeping and resting were the main activities that affected PM_(2.5)exposures of different resident groups,accounting for 60.7%-94.5%of total daily exposures.Furthermore,the long duration of sleeping makes it the predominant activity contributing to PM 25 exposure inequity.It is necessary to obtain point-to-point respiratory volume(respiratory rate)data when measuring real-time PM_(2.5)exposure data and incorporate respiratory volume(respiratory rate)into the analysis of PM_(2.5)exposure.For the first time,this study quantified the PM_(2.5)exposure inequality based on a novel method and can provide useful information for further studies on the exposure inequity.展开更多
Salt marsh plants play a vital role in mediating nitrogen(N)biogeochemical cycle in estuarine and coastal ecosystems.However,the effects of invasive Spartina alterniflora on N fixation and removal,as well as how these...Salt marsh plants play a vital role in mediating nitrogen(N)biogeochemical cycle in estuarine and coastal ecosystems.However,the effects of invasive Spartina alterniflora on N fixation and removal,as well as how these two processes balance to determine the N budget,remain unclear.Here,simultaneous quantifications of N fixation and removal via^(15)N tracing experiment with native Phragmites australis,invasive S.alterniflora,and bare flats as well as corresponding functional gene abundance by qPCR were carried out to explore the response of N dynamics to S.alterniflora invasion.Our results showed that N fixation and removal rates ranged from 0.77±0.08 to 16.12±1.13 nmol/(g·h)and from 1.42±0.14 to 16.35±1.10 nmol/(g·h),respectively,and invasive S.alterniflora generally facilitated the two processes rates.Based on the difference between N removal and fixation rates,net N_(2)fluxes were estimated in the range of-0.39±0.14 to 8.24±2.23 nmol/(g·h).Estimated net N_(2)fluxes in S.alterniflora stands were lower than those in bare flats and P.australis stands,indicating that the increase in N removal caused by S.alterniflora invasion may be more than offset by N fixation process.Random forest analysis revealed that functional microorganisms were the most important factor associated with the corresponding N transformation process.Overall,our results highlight the importance of N fixation in evaluating N budget of estuarine and coastal wetlands,providing valuable insights into the ecological effect of S.alterniflora invasion.展开更多
基金supported by Yunnan Provincial Science and Technology Project at Southwest United Graduate School(Grant No.202302AO370001)NHC Key Laboratory of Nuclear Technology Medical Transformation(MIANYANG CENTRAL HOSPITAL)(Grant No.2021HYX030 and 2021HYX006).
文摘PM_(2.5)pollution variations in different microenvironments would result in PM_(2.5)exposure inequity between rural and urban residents.In this study,the real-time PM_(2.5)exposure of urban and rural residents in China was examined based on portable PM_(2.5)sensors together with activity patterns derived from questionnaire surveys,with a focus on students and senior citizens who are sensitive to air pollution.The results showed that PM_(2.5)exposure varied significantly among different resident groups,with higher PM_(2.5)exposure of rural residents than those of urban residents.PM_(2.5)exposure peaks mostly occurred during(Accompanied)cooking activities owing to strong emissions.Sleeping and resting were the main activities that affected PM_(2.5)exposures of different resident groups,accounting for 60.7%-94.5%of total daily exposures.Furthermore,the long duration of sleeping makes it the predominant activity contributing to PM 25 exposure inequity.It is necessary to obtain point-to-point respiratory volume(respiratory rate)data when measuring real-time PM_(2.5)exposure data and incorporate respiratory volume(respiratory rate)into the analysis of PM_(2.5)exposure.For the first time,this study quantified the PM_(2.5)exposure inequality based on a novel method and can provide useful information for further studies on the exposure inequity.
基金supported by the Natural Science Foundation of China(grant numbers:42030411,42206237,41725002,41671463,41601530,and 41730646)supported by grants from China Postdoctoral Science Foundation(2021M691020).
文摘Salt marsh plants play a vital role in mediating nitrogen(N)biogeochemical cycle in estuarine and coastal ecosystems.However,the effects of invasive Spartina alterniflora on N fixation and removal,as well as how these two processes balance to determine the N budget,remain unclear.Here,simultaneous quantifications of N fixation and removal via^(15)N tracing experiment with native Phragmites australis,invasive S.alterniflora,and bare flats as well as corresponding functional gene abundance by qPCR were carried out to explore the response of N dynamics to S.alterniflora invasion.Our results showed that N fixation and removal rates ranged from 0.77±0.08 to 16.12±1.13 nmol/(g·h)and from 1.42±0.14 to 16.35±1.10 nmol/(g·h),respectively,and invasive S.alterniflora generally facilitated the two processes rates.Based on the difference between N removal and fixation rates,net N_(2)fluxes were estimated in the range of-0.39±0.14 to 8.24±2.23 nmol/(g·h).Estimated net N_(2)fluxes in S.alterniflora stands were lower than those in bare flats and P.australis stands,indicating that the increase in N removal caused by S.alterniflora invasion may be more than offset by N fixation process.Random forest analysis revealed that functional microorganisms were the most important factor associated with the corresponding N transformation process.Overall,our results highlight the importance of N fixation in evaluating N budget of estuarine and coastal wetlands,providing valuable insights into the ecological effect of S.alterniflora invasion.
