Environmentally persistent free radicals and their lifetimes in PM2.5.
Environmentally persistent free radicals and their lifetimes in PM2.5.
复制标题
DOI：
10.1021/es401767m
复制
发表时间：
2013-08-06
影响因子：
11.4
通讯作者：
Dellinger B
中科院分区：
文献类型：
--
作者：
Gehling W;Dellinger B
首次对 PM2.5 中环境持久性自由基的浓度和长期衰减行为进行了广泛研究。这项研究的结果揭示了三种类型的自由基衰变——快速衰变、慢速衰变和无衰变——遵循四种衰变模式之一：相对较快的衰变，1/e 寿命为 1-21 天，伴随缓慢衰变，1/e 寿命为 21-5028 天（47% 的样本）；一次缓慢衰变，包括 4-2083 天的 1/e 寿命（24% 的样本）；无衰减（18% 的样本）；相对较快的衰减显示平均 1/e 寿命为 0.25-21 天，随后无衰减（11% 的样品）。苯酚与初始自由基浓度和快速衰减速率密切相关。常见大气污染物（臭氧、氮氧化物、二氧化硫等）以及气象条件的其他相关性表明，光化学过程会影响初始自由基浓度和快速衰减率。 PM2.5 中的自由基信号与香烟烟雾中的半醌非常相似。因此，PM2.5吸入的自由基与吸烟吸入的自由基相关，以吸等量香烟的数量表示。计算得出，美国空气质量非极端情况下每天吸 0.4-0.9 支香烟。
For the first time, an expansive study into the concentration and extended decay behavior of environmentally persistent free radicals in PM2.5 was performed. Results from this study revealed three types of radical decay—a fast decay, slow decay, and no decay—following one of four decay patterns: a relatively fast decay exhibiting a 1/e lifetime of 1–21 days accompanied by a slow decay with a 1/e lifetime of 21–5028 days (47% of samples); a single slow decay including a 1/e lifetime of 4–2083 days (24% of samples); no decay (18% of samples); and a relatively fast decay displaying an average 1/e lifetime of 0.25–21 days followed by no decay (11% of samples). Phenol correlated well with the initial radical concentration and fast decay rate. Other correlations for common atmospheric pollutants (ozone, NOx, SO2, etc.) as well as meteorological conditions suggested photochemical processes impact the initial radical concentration and fast decay rate. The radical signal in PM2.5 was remarkably similar to semiquinones in cigarette smoke. Accordingly, radicals inhaled from PM2.5 were related to the radicals inhaled from smoking cigarettes, expressed as the number of equivalent cigarettes smoked. This calculated to 0.4–0.9 cigarettes per day for nonextreme air quality in the United States.