空气细颗粒物(PM_(2.5))污染特征及其毒性机制的研究进展

The characteristics and toxic mechanism of fine particle pollution (PM_( 2.5) ) in air

细颗粒物 (PM2 .5)是指空气动力学直径≤ 2 .5 μm的颗粒物 ,其表面吸附大量的有毒有害物质 ,并可通过呼吸沉积在肺泡 ,甚至可通过肺换气到达其他器官。由于细颗粒物的重要性 ,美国 EPA已经于 1 997年颁布了细颗粒物的空气质量标准 ,年均值为 0 .0 1 5 mg/m3,日均值为 0 .0 65 mg/m3,然而我国至今仍未制定细颗粒物空气质量标准。颗粒物上吸附的化学组分主要可分成自然来源及燃煤或燃油等人为污染来源两大类 ,特别是来自工业性和居住区燃煤及汽车燃油尾气。空气细颗粒物污染表现为形态各异、成分复杂等特征。细颗粒物有明显的毒性作用 ,可引起机体呼吸系统、免疫系统等较为广泛的损害。细颗粒物与心肺疾病密切相关 ,如增加入院率、急诊次数、呼吸疾病及症状增加、肺功能下降 ,甚至于过早死亡。

Those particles that are less than or equal to 2 5 micrometers in diameter are know as fine particles It absorb a lot of toxic compounds which can deposit in alveolus through inhalation, even transport to other organs by exchange of gas in lung Because of its importance, US EPA of enacted air quality standards of fine particles which are set at 15μg/m 3 and 65μg/m 3, respectively, for the annual and 24 hour standards But china hasn't enacted air quality standards of fine particles up to now Fine particles originate from natural sources and man made pollution, especially emission from industrial and residential combustion as well as from vehicle exhaust The characteristics of fine particles pollution are complex because of their different forms It is showed that fine particles are toxic to body , it can result in wide range damage in respiratory and immunity system Fine particles are most closely associated with health effects such as increased hospital admissions and emergency room visits for heart and lung disease, increased respiratory symptoms and disease, decreased lung function, and even premature death This paper outline the characteristics of fine particles pollution and its toxic mechanism