| Aerosol becomes hotspot of study in recent years because of having an adverse impact on climate, environment,visibility and human being. The smaller of particle diameter, the greater damage to human health, especially PM2.5and PM10caused global concern. Organic carbon (OC) and elements carbon (EC) are main components of atmospheric particulates, which is the principal reason for PM2.5and PM10causing the damage to the health of human body, visibility and climate problem etc.PM2.5and PM10were collected at one outdoor site which is the roof environment building (O1) and different typical indoor environments include common office room(Il), special printing©ing office room (12), student dormitory building (13), the classroom of environment building (14), the student canteen (15), the reading room of library (16) in QianHu campus of Nanchang university during summer (June,2009) and winter (January,2010). Pollutants level, distribution characteristics and sources of PM2.5and PM10are discussed, as well as organic carbon and the element carbon. The main research conclusions were as follows:(1) The concentration levels of PM2.5, PM10and its carbon component:In outdoor environment(Ol), the average concentration of PM2.5and PM10were89.6μg/m3and123.4μg/m3, and the average daily concentration of OC and EC of PM2.5were18.8and5.7μg/m3during summer; The average concentration of PM2.5and PM10were122.0and186.2μg/m, and the average daily concentration of OC and EC of PM2.5were22.9and7.7μg/m3during winter. The concentration of PM2.5and PM10, compared with Chinese Standard, were0.82-2.27times of standard during summer, and1.01～2.73times during winter. The concentration of PM2.5, PM10, and OC, EC compared with Heijing, Xi’an and other northern cities, were relatively low, but compared with Shanghai, Guangzhou, Hong Kong, Macau and other southern cities, were on the high side. It is polluted severely relative to some foreign cities. The average concentrations of PM2.5and PM10of Nanchang were9.8and7.0times of that of Birmingham in winter. The average concentrations of OC and EC in PM2.5of Nanchang were8.9and29.6times of that of the United States Alan parker in winter, and4.7and1.7times of that of Cheongju of Korea in winter.(2) The distribution of day and night:In sampling point01, the average concentration of PM2.5in daytime and nighttime during the summer period were96.8μg/m3and109.2μg/m3, and which were93.1and93.7μg/m3in I1site. The average concentration of OC in PM2.5in daytime and nighttime during the summer period wereμg/m324.0and26.7μg/m3, and for EC, which were5.2and8.0μg/m3; In sampling point I1, for OC, which were26.1and27.3μg/m3, and for EC, which were4.9and7.8μg/m3; OC and EC present higher in nighttime and lower in daytime, which reason was mainly attributed to the difference mixing layer depth between nighttime and daytime; The concentrations of SOC in daytime and nighttime during the summer period were14.1and11.4μg/m3. Which was higher in daytime than which is in nighttime. It was believed higher temperature and more intense solar radiation during daytime provided favorable conditions for photochemical activities and SOC formation.(3) The distribution of particle size:The ratio of PM2.5and PM10were0.595～0.795in summer and0.591-0.865in winter, which indicated PM2.5was in high proportion of PM10. There are good correlations with the concentration of PM2.5and which of PM10. The square of correlation coefficient in summer and winter were0.877and0.6628. It said that PM2.5and PM10have the same contamination source.(4) The distribution of PM2.5between indoor and outdoor:The concentrations of PM2.5in01site were higher than that in I1,and lower than12and13site in summer, and which in01site were higher than I1,12,13,14and16site, and lower15site in winter. Through the T test, there are uncorrelated with indoor-outdoor correlations with concentrations of PM2.5between01and I1site,01and13site of the summer and winter. The square of correlation coefficient of01and I1site,01and13site in summer were0.5167and0.2257, and0.4566and0.0072in winter. Which was caused by poor ventilation,indoor source in I1and13site..(5) The distribution of OC and EC between indoor and outdoor:The orders of the concentrations of OC of PM2.5in summer was as follows I2> I3>I1>O1, and for EC, which was O1>I1>I2and O1>13. For OC in winter, which was I2> I5>16> O1>13> I4> I1, and for EC, which was I5>16> O1>12> I4>13=I1. The comparison results of OC brtween indoor and outdoor reflected there OC emissions in the indoor, especially there were obvious OC emissions in printing room(I2); The cookers in student canteen (I5) made contribution to OC and EC of indoor. The library (I6) lies on downwind direction of canteen,which caused high concentrations of OC and EC. The inspection results of correlation of OC and EC between indoor and outdooe (O1-I1:outdoor-office; O1-I3:outdoor-student dormitory):The correlation of indoor-ourdoor of OC was less obvious, and which is good correlations for EC, which is reflected that there are some different sources both indoor and outdoor for OC, and the sources of EC between indoor and outdoor have few differences.(6) The seasonal distribution:The regularity displayed by the concentrations of PM2.5is lower in summer and higher in winter; For the concentrations of OC and EC in O1site and EC in I2and I3site were also lower in summer and higher in winter, There more southerly winds blowing in Nanchang during summer, and which will blow clean air from equatorial Pacific and the South China Sea to this region, in winter weather, northerly winds blowing more than, the polluted air will be blowed from inland to this region. The concentrations of OC and EC in I1and OC in I2and I3site were higher in summer and lower in winter, which is may relevanted to that summer is positive for the formation of secondary organic.(7) The maximum contribution of the concentrations of OC, TC and TCA to PM2.5is in I2site,I5and I6site is only second to12. The eighet carbon components have obvious difference carbon sources in I2,I5and I6site. The contribution of TCA is more than a third of the mass of PM2.5, which showed that OC and EC is the important ingredient of fine particles.(8) The conclusion obtained by the factor analysis showed that the carbonaceous of PM2.5is mainly from gasoline vehicles, coal-fired fumes and burning biomass, and the maximum ratio of the sources is gasoline vehicles, the overriding reason is that Qianhu campus of nanchang university is next to ChangZhang Highway.(9) The contributions of OCin-real to TC in I2site is higher, and which contribution is52.0%in summer and48.3%in winter, which indicated that a mass of OC or the precursors of secondary organic were emissioned from printing©ing office room; The contributions of ECin-real to TC in15and16site are also special, which contribution is7.6%and8.1%, which is mainly relate to burning stov in15site, and the library (16) lies on downwind direction of canteen(I5) causing northerly winds blowing in winter. |
PDF Full Text Request