[目的]研究沙尘天气及沙尘颗粒物（PM2.5、PM10）与呼吸、心血管系统疾病日入院人数的关系。[方法]采用时间序列的半参数广义相加模型（Semi-parametric generalized additive model，GAM），在控制了长期趋势、星期几效应（day of the ...[目的]研究沙尘天气及沙尘颗粒物（PM2.5、PM10）与呼吸、心血管系统疾病日入院人数的关系。[方法]采用时间序列的半参数广义相加模型（Semi-parametric generalized additive model，GAM），在控制了长期趋势、星期几效应（day of the week，DOW）以及气象因子等混杂因素的影响后，分析2004年春季沙尘PM2.5和PM10及其大气污染物（SO2和NO2）与呼吸、心血管系统疾病日入院人数的关系，并将沙尘PM2.5和PM10按浓度分类探讨不同沙尘天气对人体健康的影响。[结果]①沙尘PM2.5和PM10在单污染模型中对居民呼吸和心血管系统疾病日入院人数的影响在滞后第2天和第3天有统计学意义。多污染模型分析表明，引入SO2或（和）NO2后，PM10对呼吸和心血管系统疾病日入院人数的影响有统计学意义，PM2.5对心血管系统疾病日入院人数的影响有统计学意义。在模型中引入其他污染物后，SO2和NO2对呼吸和心血管系统日入院人数的影响均无统计学意义。②颗粒物浓度分类模型分析表明，沙尘天气PM2.5只有达到沙尘暴颗粒物水平（〉167．5μg／m^3）对男性呼吸和心血管系统疾病日入院人数的影响才有意义，而对女性的影响PM2.5在扬沙天气水平（95．4～167．5μg/m^3）就有意义。沙尘天气PM10对男、女性呼吸和心血管系统健康的影响在扬沙天气水平（150～250μg／m^3）就有意义，达到沙尘暴水平时，其影响达到最大。[结论]①在几乎没有工业污染的沙尘发生源区或近源区，其沙尘PM2.5、PM10只有达到较高浓度（扬沙天气水平）时，才会对居民呼吸和心血管系统疾病日入院人数有影响，且为滞后效应，并呈一定剂量效应关系，即：沙尘暴天〉扬沙天〉沙尘轻度污染天、清洁天；②本研究根据大气PM10和PM2.5水平划分沙尘天气类型．比以能见度划分更为科学且更易操作．同时也为我国制定PM10和PM2.5�展开更多
Wall-mounted swirling ventilation is a new type of system in mechanized excavation faces with a dust sup-pression performance that is closely related to the blowing-to-suction flow ratio.Physical and simulation models...Wall-mounted swirling ventilation is a new type of system in mechanized excavation faces with a dust sup-pression performance that is closely related to the blowing-to-suction flow ratio.Physical and simulation models were developed according to the No.C103 mechanized excavation face in the Nahe Coal Mine of the Baise Mining Bureau,Guangxi Province to optimize the blowing-to-suction flow ratio for wall-mounted swirling ventilation.Both the k-εturbulence model and the discrete phase model were utilized to simulate airflow field structures and dust concentration distribution patterns at various blowing-to-suction flow ratios.The results suggest that higher blowing-to-suction flow ratios increase the airflow field disturbance around the working face and weaken the intensity of the axial air curtain.On the other hand,both the intensity of the radial air curtain and the dust suppression effect are enhanced.At a blowing-to-suction flow ratio of 0.8,the wall-mounted swirling ventilation system achieved the most favorable dust suppression performance.Both the total dust and respirable dust had their lowest concentrations with maximum efficiencies of reducing both types at 90.33%and 87.16%,respectively.展开更多
We analyzed dust event occurrence and its seasonal distribution at 16 sites in the Tarim Basin,China.Although the overall frequency of dust events was the highest in spring in this region,its variation in other season...We analyzed dust event occurrence and its seasonal distribution at 16 sites in the Tarim Basin,China.Although the overall frequency of dust events was the highest in spring in this region,its variation in other seasons could be classified into three patterns:(1) frequency of dust events in autumn > that in summer > that in winter(at the Kashi and Kuche sites);(2) frequency in summer > that in winter > that in autumn(at the Ruoqiang site);and(3) frequency in summer > that in autumn > that in winter(at all other areas of the Tarim Basin).The frequency of dust events and their seasonal variations in the Tarim Basin were mainly controlled by wind speed and locally available dust sources;the former was the key control when dust sources did not differ significantly.The seasonal variation in evaporation had a smaller,but still significant effect on the frequency of dust events.展开更多
文摘[目的]研究沙尘天气及沙尘颗粒物（PM2.5、PM10）与呼吸、心血管系统疾病日入院人数的关系。[方法]采用时间序列的半参数广义相加模型（Semi-parametric generalized additive model，GAM），在控制了长期趋势、星期几效应（day of the week，DOW）以及气象因子等混杂因素的影响后，分析2004年春季沙尘PM2.5和PM10及其大气污染物（SO2和NO2）与呼吸、心血管系统疾病日入院人数的关系，并将沙尘PM2.5和PM10按浓度分类探讨不同沙尘天气对人体健康的影响。[结果]①沙尘PM2.5和PM10在单污染模型中对居民呼吸和心血管系统疾病日入院人数的影响在滞后第2天和第3天有统计学意义。多污染模型分析表明，引入SO2或（和）NO2后，PM10对呼吸和心血管系统疾病日入院人数的影响有统计学意义，PM2.5对心血管系统疾病日入院人数的影响有统计学意义。在模型中引入其他污染物后，SO2和NO2对呼吸和心血管系统日入院人数的影响均无统计学意义。②颗粒物浓度分类模型分析表明，沙尘天气PM2.5只有达到沙尘暴颗粒物水平（〉167．5μg／m^3）对男性呼吸和心血管系统疾病日入院人数的影响才有意义，而对女性的影响PM2.5在扬沙天气水平（95．4～167．5μg/m^3）就有意义。沙尘天气PM10对男、女性呼吸和心血管系统健康的影响在扬沙天气水平（150～250μg／m^3）就有意义，达到沙尘暴水平时，其影响达到最大。[结论]①在几乎没有工业污染的沙尘发生源区或近源区，其沙尘PM2.5、PM10只有达到较高浓度（扬沙天气水平）时，才会对居民呼吸和心血管系统疾病日入院人数有影响，且为滞后效应，并呈一定剂量效应关系，即：沙尘暴天〉扬沙天〉沙尘轻度污染天、清洁天；②本研究根据大气PM10和PM2.5水平划分沙尘天气类型．比以能见度划分更为科学且更易操作．同时也为我国制定PM10和PM2.5�
基金support for this work was provided by the National Natural Science Foundation of China(No.51574123)the Scientific Research Project of Hunan Province Office of Education(No.18A185),which are gratefully acknowledged.
文摘Wall-mounted swirling ventilation is a new type of system in mechanized excavation faces with a dust sup-pression performance that is closely related to the blowing-to-suction flow ratio.Physical and simulation models were developed according to the No.C103 mechanized excavation face in the Nahe Coal Mine of the Baise Mining Bureau,Guangxi Province to optimize the blowing-to-suction flow ratio for wall-mounted swirling ventilation.Both the k-εturbulence model and the discrete phase model were utilized to simulate airflow field structures and dust concentration distribution patterns at various blowing-to-suction flow ratios.The results suggest that higher blowing-to-suction flow ratios increase the airflow field disturbance around the working face and weaken the intensity of the axial air curtain.On the other hand,both the intensity of the radial air curtain and the dust suppression effect are enhanced.At a blowing-to-suction flow ratio of 0.8,the wall-mounted swirling ventilation system achieved the most favorable dust suppression performance.Both the total dust and respirable dust had their lowest concentrations with maximum efficiencies of reducing both types at 90.33%and 87.16%,respectively.
基金the funding from the Natural Science Foundation of China (Grant No. 40638038)
文摘We analyzed dust event occurrence and its seasonal distribution at 16 sites in the Tarim Basin,China.Although the overall frequency of dust events was the highest in spring in this region,its variation in other seasons could be classified into three patterns:(1) frequency of dust events in autumn > that in summer > that in winter(at the Kashi and Kuche sites);(2) frequency in summer > that in winter > that in autumn(at the Ruoqiang site);and(3) frequency in summer > that in autumn > that in winter(at all other areas of the Tarim Basin).The frequency of dust events and their seasonal variations in the Tarim Basin were mainly controlled by wind speed and locally available dust sources;the former was the key control when dust sources did not differ significantly.The seasonal variation in evaporation had a smaller,but still significant effect on the frequency of dust events.
