A severe Asian Dust Storm （ADS） event occurred on 16-17 April 2006 in northern China. The mineral compositions of dust samples were analyzed using X-ray diffraction （XRD）. The results indicated that dust particles...A severe Asian Dust Storm （ADS） event occurred on 16-17 April 2006 in northern China. The mineral compositions of dust samples were analyzed using X-ray diffraction （XRD）. The results indicated that dust particles of the ＂17 April 2006＂ dust storm were dominated by quartz （37.4%） and clay （32.9%）, followed by plagioclase （13.7%）, with small amounts of calcite, K-feldspar, dolomite, hornblende and gypsum （all less than 10%）. The clay fractions with diameter less than 2 μm were separated from the dust storm particles by centrifuging and were further analyzed by XRD. The results revealed that the clay species were mainly illite/smectite mixed layers （I/S） （49%） and illite （34%）, with small amount of kaolinite （8%） and chlorite （9%）. In order to evaluate the feasibility of using the mineralogy to trace the sources of dust particles, the XRD results of the ＂17 April 2006＂ dustfall particles were compared with the dust particles over past years. The results confirmed that the finer dust particles represented by the ADS PM10 displayed a smaller quartz/clay ratio than the dustfall particles. The dust storm particles, either from the ADS PM10 or from the ＂17 April 2006＂ dustfall, showed a lower level of dolomite contents and lower dolomite/clay ratios compared with the non-dust storm dustfall particles. This implies that dolomite could be used to distinguish between the dust contributions from local and non-local sources. Similar trends were found for the gypsum and the gypsum/clay ratio. Moreover, the two dustfall samples had a lower level of illite/smectite mixed layers and a higher level of illite than airborne PM10, implying that the dustfall particles tend to be enriched with illite in its clay fraction.展开更多
Strontium has four naturally occurring stable isotopes,84Sr,86Sr,87Sr,and 88Sr,with abundances of 0.56,9.87,approximately 7.04,and 82.53 atomic %,respectively.The 87Sr/86Sr isotope ratio is variable due to the additio...Strontium has four naturally occurring stable isotopes,84Sr,86Sr,87Sr,and 88Sr,with abundances of 0.56,9.87,approximately 7.04,and 82.53 atomic %,respectively.The 87Sr/86Sr isotope ratio is variable due to the addition of radiogenic 87Sr produced by the beta decay of 87Rb with a half-life of 4.88 ± 0.05 Ga.Thus,展开更多
A simple method for estimating the contributions of mineral dust to PM2.5, PM10, or TSP is presented. The method is based on the assumption of external mixing of two types of particles with different PM2.5/PM10 ratios...A simple method for estimating the contributions of mineral dust to PM2.5, PM10, or TSP is presented. The method is based on the assumption of external mixing of two types of particles with different PM2.5/PM10 ratios, The method was applied to local and transported dust events observed in Tsukuba, Japan, and was compared with collocated polarization lidar measurements. The method was then applied to three dust events that occurred in Oki, Rishiri, and Ochiishi,Japan, in 2012. The results showed that the method was useful for detecting mineral dust and for qualitatively describing the mixing of dust with anthropogenic aerosols.展开更多
基金National Basic Research Program of China （Grant No. 2006CB403701） the National Natural Science Foundation of China （Grant No. 40575065）.
文摘A severe Asian Dust Storm （ADS） event occurred on 16-17 April 2006 in northern China. The mineral compositions of dust samples were analyzed using X-ray diffraction （XRD）. The results indicated that dust particles of the ＂17 April 2006＂ dust storm were dominated by quartz （37.4%） and clay （32.9%）, followed by plagioclase （13.7%）, with small amounts of calcite, K-feldspar, dolomite, hornblende and gypsum （all less than 10%）. The clay fractions with diameter less than 2 μm were separated from the dust storm particles by centrifuging and were further analyzed by XRD. The results revealed that the clay species were mainly illite/smectite mixed layers （I/S） （49%） and illite （34%）, with small amount of kaolinite （8%） and chlorite （9%）. In order to evaluate the feasibility of using the mineralogy to trace the sources of dust particles, the XRD results of the ＂17 April 2006＂ dustfall particles were compared with the dust particles over past years. The results confirmed that the finer dust particles represented by the ADS PM10 displayed a smaller quartz/clay ratio than the dustfall particles. The dust storm particles, either from the ADS PM10 or from the ＂17 April 2006＂ dustfall, showed a lower level of dolomite contents and lower dolomite/clay ratios compared with the non-dust storm dustfall particles. This implies that dolomite could be used to distinguish between the dust contributions from local and non-local sources. Similar trends were found for the gypsum and the gypsum/clay ratio. Moreover, the two dustfall samples had a lower level of illite/smectite mixed layers and a higher level of illite than airborne PM10, implying that the dustfall particles tend to be enriched with illite in its clay fraction.
文摘Strontium has four naturally occurring stable isotopes,84Sr,86Sr,87Sr,and 88Sr,with abundances of 0.56,9.87,approximately 7.04,and 82.53 atomic %,respectively.The 87Sr/86Sr isotope ratio is variable due to the addition of radiogenic 87Sr produced by the beta decay of 87Rb with a half-life of 4.88 ± 0.05 Ga.Thus,
文摘A simple method for estimating the contributions of mineral dust to PM2.5, PM10, or TSP is presented. The method is based on the assumption of external mixing of two types of particles with different PM2.5/PM10 ratios, The method was applied to local and transported dust events observed in Tsukuba, Japan, and was compared with collocated polarization lidar measurements. The method was then applied to three dust events that occurred in Oki, Rishiri, and Ochiishi,Japan, in 2012. The results showed that the method was useful for detecting mineral dust and for qualitatively describing the mixing of dust with anthropogenic aerosols.
