ASSOCIATION OF PARTICULATE AIR-POLLUTION AND ACUTE MORTALITY - INVOLVEMENT OF ULTRAFINE PARTICLES
ASSOCIATION OF PARTICULATE AIR-POLLUTION AND ACUTE MORTALITY - INVOLVEMENT OF ULTRAFINE PARTICLES
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DOI：
10.3109/08958379509014275
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发表时间：
1995-01-01
影响因子：
2.1
通讯作者：
WEISS, B
中科院分区：
文献类型：
--
作者：
OBERDORSTER, G;GELEIN, RM;WEISS, B
最近的流行病学研究表明，颗粒物空气污染与急性死亡率和发病率之间存在关联，其范围可低至环境颗粒物浓度低于100微克/立方米(3)。这种关联是否也意味着急性健康影响和低水平颗粒物暴露之间的因果关系目前尚不清楚；目前还不知道可以解释低环境颗粒物浓度如此戏剧性影响的机制。根据我们过去和最近对大鼠吸入超细颗粒的研究结果，我们认为这种颗粒，即直径小于50纳米的颗粒，可能与观察到的死亡率和发病率的增加有关。在过去，我们证明吸入高不溶性、低固有毒性的颗粒物，如二氧化钛，当其大小在超细颗粒范围内时，会导致肺部炎症反应显著增加，直径类似于20 nm。然而，这些影响并不是急性的，只有在长期吸入浓度在每立方米毫克范围内的聚集超细颗粒后才会发生。相反，在我们最近对聚四氟乙烯(PTFE)热降解产物的研究过程中，我们发现，新产生的含有单线态超细颗粒(中值直径26 nm)的PTFE烟雾在0.7-1.0x10(6)颗粒/厘米(3)的吸入浓度下对大鼠具有高度毒性，导致急性出血性肺部炎症和暴露10-30分钟后死亡。我们还发现，聚四氟乙烯烟雾暴露严重影响了大鼠在转轮上的工作表现。这些结果证实了其他实验室的报告，即聚四氟乙烯烟雾具有高度毒性，不能归因于这些烟雾的气相成分，如HF、羰基氟化物或全氟异丁烯，或活性自由基。我们研究中吸入的超细聚四氟乙烯粒子的计算质量浓度小于60微克/立方米(3)，这是导致健康大鼠死亡的一个非常低的值。伴随着超细颗粒聚集的烟雾的老化显著降低了它们的毒性。由于超细颗粒物总是存在于城市大气中，我们认为它们在导致人口中敏感地区的急性肺损伤中发挥了作用。
Recent epidemiological studies show an association between particulate air pollution and acute mortality and morbidity down to ambient particle concentrations below 100 mu g/m(3). Whether this association also implies a causality between acute health effects and particle exposure al these low levels is unclear at this time; no mechanism is known that would explain such dramatic effects of low ambient particle concentrations. Based on results of our past and most recent inhalation studies with ultrafine particles in rats, we propose that such particles, that is, particles below similar to 50 nm in diameter, may contribute to the observed increased mortality and morbidity. In the past we demonstrated that inhalation of highly insoluble particles of low intrinsic toxicity, such as TiO2, results in significantly increased pulmonary inflammatory responses when their size is in the ultrafine particle range, similar to 20 nm in diameter. However, these effects were not of an acute nature and occurred only after prolonged inhalation exposure of the aggregated ultrafine particles at concentrations in the milligrams per cubic meter range. In contrast, in the course of our most recent studies with thermodegradation products of polytetrafluoroethylene (PTFE) we found that freshly generated PTFE fumes containing singlet ultrafine particles (median diameter 26 nm) were highly toxic to rats at inhaled concentrations of 0.7-1.0 x 10(6) particles/cm(3), resulting in acute hemorrhagic pulmonary inflammation and death after 10-30 min of exposure. We also found that work performance of the rats in a running wheel was severely affected by PTFE fume exposure. These results confirm reports from other laboratories of the highly toxic nature of PTFE fumes, which cannot be attributed to gas-phase components of these fumes such as HF, carbonylfluoride, or perfluoroisobutylene, or to reactive radicals. The calculated mass concentration of the inhaled ultrafine PTFE particles in our studies was less than 60 mu g/m(3), a very low value to cause mortality in healthy rats. Aging of the fumes with concomitant aggregation of the ultrafine particles significantly decreases their toxicity. Since ultrafine particles are always present in the urban atmosphere, we suggest that they play a role in causing acute lung injury in sensitive parts of the population.