加州理工研究：洛杉矶伊顿火灾烟雾铅含量超野火烟雾50倍，近700万人曾暴露于80倍铅浓度
加州理工学院科学家10月28日在《科学进展》（Science Advances）期刊发表研究指出，2025年1月伊顿火灾期间，洛杉矶城市烟雾中的铅含量是普通野火烟雾的50多倍。在建筑燃烧最剧烈的阶段，洛杉矶大都会区近700万人在24小时内暴露于平时80倍的铅浓度。这项研究由博士研究生哈鲁拉·巴利亚卡（Haroula Baliaka）领衔，合著者包括瑞安·沃德（Ryan Ward），通讯作者为恩加·李（萨莉）·吴教授（Nga Lee "Sally" Ng）与理查德·弗拉根教授（Richard Flagan），论文编号 DOI: 10.1126/sciadv.aei4455。
研究团队在阿尔塔迪纳以南约11英里的 Pico Rivera 设监测站采样，该站是 ASCENT 监测网络的12个站点之一。数据显示，城市烟雾中的氯与溴含量约为野火烟雾的7倍，砷约为3倍；作为对比样本的2024年9月河滨县机场火灾（过火24,000英亩、烧的是植被）烟雾成分与之显著不同。研究人员以钾与铅的比例追踪烟雾来源变化：1月8日至9日该比例约为5比1，1月11日约为50比1，1月12日升至数百比1，显示随着建筑燃烧减弱，来自建筑材料的铅在烟雾中的占比逐步下降。
研究团队表示，这种铅暴露对健康的实际影响目前尚不清楚，有待进一步研究；本研究结论是伊顿火灾的城市烟雾成分与烧植被的野火烟雾有本质区别，因为烧毁的是整片社区的建筑与其中物品。
伊顿火灾是2025年1月洛杉矶系列山火中破坏最严重的火灾之一，共烧毁9,000多栋建筑，造成19人死亡，逾10万人被迫疏散。
关联：洛杉矶县｜伊顿火灾烧毁的 Altadena 公园动土重建
Caltech Study: Los Angeles Eaton Fire Smoke Carried More Than 50 Times the Lead of Wildfire Smoke, With Nearly 7 Million People Exposed to 80 Times Typical Lead Levels
Caltech scientists reported on October 28 in the journal Science Advances that during the January 2025 Eaton Fire, lead levels in Los Angeles urban smoke were more than 50 times those in ordinary wildfire smoke. During the phase of most intense building burning, nearly 7 million people across the Los Angeles metropolitan area were exposed within 24 hours to lead concentrations 80 times typical levels. The study was led by doctoral researcher Haroula Baliaka, with co-author Ryan Ward and corresponding authors Professor Nga Lee "Sally" Ng and Professor Richard Flagan (DOI: 10.1126/sciadv.aei4455).
The team sampled air at a monitoring station in Pico Rivera, about 11 miles south of Altadena, one of 12 stations in the ASCENT network. Chlorine and bromine in the urban smoke measured about seven times wildfire-smoke levels, and arsenic about three times. The comparison case was the September 2024 Airport Fire in Riverside County, which burned 24,000 acres of vegetation. Tracking the potassium-to-lead ratio, the researchers found it was about 5 to 1 on January 8-9, about 50 to 1 on January 11, and rose to hundreds to 1 by January 12, showing the share of building-derived lead falling as structural burning subsided.
The researchers said the actual health effects of this lead exposure remain unclear and require further study. Their central finding is that urban smoke from the Eaton Fire differed fundamentally from vegetation wildfire smoke, because what burned was an entire community's buildings and contents.
The Eaton Fire was among the most destructive of the January 2025 Los Angeles fires, destroying more than 9,000 structures, killing 19 people and forcing more than 100,000 residents to evacuate.
Related: LA County | Eaton Fire-Destroyed Altadena Park Breaks Ground on Rebuild
来源：GSM·美国（原文链接）
图片来源：图：伊顿火灾之后的阿尔塔迪纳乡村俱乐部（Altadena Town and Country Club）景象，为火灾后建筑残骸、非烟雾实测现场。洛杉矶县政府摄，公共领域，经 Wikimedia Commons。 / The Altadena Town and Country Club after the Eaton Fire; post-fire structural damage, not a smoke measurement site. Los Angeles County photo, public domain, via Wikimedia Commons.
