Cicero-Fernández P, Thistlewaite W A, Falcon Y I, Guzmán I M
Environmental Science and Engineering Program, School of Public Health, University of California, Los Angeles 90024-1772, USA.
J Expo Anal Environ Epidemiol. 1993;3 Suppl 1:1-14.
Data for PM10 and TSP collected from SEDUE's (Secretary of Urban Development and Ecology) five principal air monitoring stations from March of 1988 to March of 1989 were analyzed with an emphasis on spatial and temporal distributions. The Mexico City sites consisted of a mixed residential and industrial setting in the NW, a highly industrialized area in the NE, the commercial and administrative district downtown, and areas in the SW and SE dominated by residential neighborhoods. High volume samplers for TSP and PM10 running in parallel were used following a protocol similar to the one specified by the U.S. Environmental Protection Agency. The individual data collected ranged from 24 to 1494 micrograms/m-3 for TSP and from 17 to 607 micrograms/m-3 for PM10. The PM10-to-TSP ratios ranged from 0.104 to 0.914 for a one year period, 0.495 being the overall mean ratio. Seasonal and geographical differences in this ratio may reflect the range of sources, transport and transformations of primary and secondary particles. High concentrations of particles were found during the winter and early spring, followed by relatively low concentrations during the summer. Statistically significant differences were found for the two most contrasting sites, the NE and SW areas of the city. The northern and eastern parts were the most impacted by particulate matter, while the area at the southwestern edge of the city was least polluted by fine and total suspended particles. Two interesting observations have emerged from this analysis. First, there is the exceedingly high daily and annual values for both TSP and PM10, relative to the Mexican and U.S. standards and WHO criteria for particulate matter. Second, although the SW area of Mexico City had the lowest fine suspended particle concentrations, it is in this area that the highest concentrations of ozone have been observed.
分析了1988年3月至1989年3月期间从城市发展与生态秘书处（SEDUE）的五个主要空气监测站收集的PM10和总悬浮颗粒物（TSP）数据，重点关注其空间和时间分布。墨西哥城的监测点包括西北部一个混合了住宅和工业的区域、东北部一个高度工业化的地区、市中心的商业和行政区，以及西南部和东南部以居民区为主的区域。按照类似于美国环境保护局规定的方案，使用了并行运行的TSP和PM10大容量采样器。收集到的TSP个体数据范围为24至1494微克/立方米，PM10为17至607微克/立方米。一年期间，PM10与TSP的比值范围为0.104至0.914，总体平均比值为0.495。该比值的季节性和地理差异可能反映了一次和二次颗粒物的来源、传输及转化范围。冬季和早春发现颗粒物浓度较高，随后夏季浓度相对较低。在城市中两个反差最大的区域，即东北部和西南部地区，发现了具有统计学意义的差异。城市的北部和东部受颗粒物影响最大，而城市西南边缘地区的细颗粒物和总悬浮颗粒物污染最少。从该分析中出现了两个有趣的现象。第一，相对于墨西哥和美国的标准以及世界卫生组织的颗粒物标准，TSP和PM10的每日和年度值都极高。第二，尽管墨西哥城的西南部地区细悬浮颗粒物浓度最低，但正是在该地区观测到了最高浓度的臭氧。
