| N, N-Dimethylformamide (DMF) is a toxic and hazardous pollutant which affects many organ systems such as digestive system, respiratory system and reproductive system, and even may have carcinogenic effects on human body. As the largest DMF consumer worldwide, there are large amounts of DMF exposure population in our country. With the rapid increase of consumption, DMF exposure population keeps on growing and will suffer from more and more serious health risk. As a non-conventional pollutant, there are no monitoring stations of DMF in the urban area. So, limited data on concentration levels of DMF could be obtained. Thus, the questions such as what level of DMF concentrations in the ambient air, what effect of DMF exposure on human health, whether there is relationship between DMFexposure and a certain disease and what health risk it is, still could not be answered. As a result, effective measures could not be taken to reduce human exposure to health risks.To solve these problems, this research established DMF emission inventory based on emission minitoring data and investigation of synthetic leather factory. After adaptability adjusting of the air dispersion model, it was used to simulate spatial and temporal distribution of DMF with fine grids to obtain annual and daily average concentrations of DMF between 1999 and 2008.We proposed GIS-based population and activity weighted exposure assessment method, investigated GIS-based population distribution and selected a total of 1289 household representatives to survey information on movement characteristics. Subsequently, population movement patterns were combined with DMF concentration levels on maps of 100 m×100 m resolution to calculate annual and daily average population exposure of DMF between 1999 and 2008 and DMF population exposure of different occupation groups. Using multifactors logistic regression analysis method, after controlling for confounding factors, we studied DMF exposure effect on liver disease, respiratory disease, digestive disease, cardiovascular disease and cancer. Using poisson regression-based semi-parametric generalized additive model, after controlling for confounding factors, we studied relationship between DMF exposure and daily inpatients of respiratory disease, digestive disease, cardiovascular disease and total disease. We assessed GIS-based helath risk of DMF between 1999 and 2008 and calculated health risk of different occupation groups. Furthermore, we studied relationship between DMF population exposure (DMF concentration) and health risk and proposed standard for DMF concentration and population exposure DMF concentration under the risk threshold.The main results and conclusions of this research are as follows:(1) Between 1999 and 2008, annual average and daily concentration of DMF was in the range of 0.09～0.85 mg/m3 and rang of 0.003 mg/m3-4.61 mg/m3, respectively. With the increase of production lines, DMF concentration increased since 1999 and achieved maximum emission in 2002. Then, with running of pollution control facilities, DMF emission decreased to the minimum value in 2008. Fugitive emission of DMF was the largest contributor of the ambient DMF concentrations. Collect and dispose DMF from fugitive emission is the effective way to reduce DMF ambient concentration. It is reliable to obtain the temporal and spatial concentration distribution of pollutants using air dispersion model. This method resolves the problem that the popupaltion exposure can not be evaluated without the monitoring concentration of pollutant. Using this method can also obtain the long term concentrations of pollutant and provide concentration distribution for population exposure assessment.(2) Annual average concentration of DMF between 1999 and 2008 was in the range of 0.09～0.88mg/m3. High population densities occurred in regions of low DMF pollution. DMF population exposure of different occupation groups was between 0.034 mg/m3 and 0.082 mg/m3. The retired people were the high exposure group because they spent most time at home where DMF concentration was high. There was a substantial impact of movement patterns on the evaluation of population exposure. Population exposure based on movement characteristics could better reflect the impact of pollutants on human health.(3) Long term exposure to DMF would increase the risk of hospitalization of liver disease, respiratory disease, digestive disease, cardiovascular disease and cancer, expecially for digestive and cardiovascular disease, which OR (95%CI) was 1.272 (1.062～1.523) and 1.578 (1.205～2.066), respectively. Short term exposure to DMF, when DMF expocure concentration increases IQR, increase percentage (95%CI) of daily inpatients of respiratory diseases, digestive diseases, cardiovascular disease, total disease (total number, male and female) was 9.3% (1.17%～18.06%),10.62%(4.04%～17.62%),4.44%(-5.2%～15.07%),7.11%(4.18%～10.12%), 4.33%(0.28%～8.54%) and 9.73%(5.69%～13.94%), respectively. The higher risks were found on respiratory diseases and digestive diseases and female (compared with male). There may exsit the difference of DMF exposure impact on different sex group, which may relate with DMF detoxification mechanism.(4) Annual average health risk of DMF between 1999 and 2008 was in the range of 2.12～20.21 mg/m3. DMF human health risk of 2008 was between 0.038 and 14.78 and the average value was 2.076. Population in the study area was exposed to the medium risk level of DMF and the ambient air was the primary source of DMF health risk. DMF health risk of different occupation groups was between 0.038 mg/m3 and 14.78 mg/m3 (average value was 2.076) and indicated that retired people had the highest health risk.(5) If DMF health risk was at the level of lower than 0.1,0.1～10 and higher than 10, then population exposure was in the range of 0-0.004 mg/m3,0.004-0.43mg/m3 and higher than 0.43mg/m3, and DMF ambient concentration was in the range of 0～0.011 mg/m3, 0.011-0.46mg/m3 higher than 0.46mg/m3. We proposed 0.23mg/m3 and 0.22 mg/m3 as the control limits of DMF population exposure and DMF ambient concentration (risk factor was controlled within 5)...
|
PDF Full Text Request