A Wide Area of Air Pollutant Impact Downwind of a Freeway during Pre-Sunrise Hours.
A Wide Area of Air Pollutant Impact Downwind of a Freeway during Pre-Sunrise Hours.
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DOI：
10.1016/j.atmosenv.2009.02.033
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发表时间：
2009-05-01
影响因子：
5
通讯作者：
Winer, Arthur M.
中科院分区：
文献类型：
--
作者：
Hu, Shishan;Fruin, Scott;Kozawa, Kathleen;Mara, Steve;Paulson, Suzanne E.;Winer, Arthur M.
我们已经观察到了大面积的空气污染物的影响下风向的高速公路在日出前的时间在冬季和夏季。相比之下，以前的研究表明，高速公路下风向的空气污染物梯度要尖锐得多，高于背景浓度的水平在白天仅延伸到道路下风向300米，在夜间可达500米。在这项研究中，实时空气污染物浓度测量沿着3 600 m的横断面垂直于高架高速公路1-2小时前日出使用电动汽车移动的平台配备了快速响应仪器。在冬季日出前的几个小时，超细颗粒（UFP）浓度峰值（约95 000 cm−3）出现在高速公路的下风向。然而，下风向UFP浓度高达约40 000 cm−3，从高速公路延伸至少1 200 m，并没有达到背景水平（约15 000 cm−3），直到约2 600 m的距离。超微粒子浓度也高于背景水平高达600米的高速公路逆风。其他污染物，如NO和颗粒结合的多环芳烃，表现出类似的长距离顺风浓度梯度。相反，空气污染物浓度在同一路线上测量后，日出，在上午和下午，表现出典型的白天顺风下降到背景水平内约300米，发现在早期的研究。虽然日出前的高速公路上的交通量远低于白天的拥堵高峰，顺风UFP浓度显着高于日出前的时间比白天; UFP和NO浓度也与高速公路上的交通计数密切相关。我们将这些日出前浓度升高的区域与夜间表面温度逆温，低风速和高相对湿度相关联。观测日出前主要道路顺风处的大范围空气污染物影响区域具有重要的暴露评估意义，因为它表明在日出前几个小时（大多数人都在家），道路对居民区有广泛的影响。
We have observed a wide area of air pollutant impact downwind of a freeway during pre-sunrise hours in both winter and summer seasons. In contrast, previous studies have shown much sharper air pollutant gradients downwind of freeways, with levels above background concentrations extending only 300 m downwind of roadways during the day and up to 500 m at night. In this study, real-time air pollutant concentrations were measured along a 3 600 m transect normal to an elevated freeway 1–2 hours before sunrise using an electric vehicle mobile platform equipped with fast-response instruments. In winter pre-sunrise hours, the peak ultrafine particle (UFP) concentration (~95 000 cm−3) occurred immediately downwind of the freeway. However, downwind UFP concentrations as high as ~ 40 000 cm−3 extended at least 1 200 m from the freeway, and did not reach background levels (~15 000 cm−3) until a distance of about 2 600 m. UFP concentrations were also elevated over background levels up to 600 m upwind of the freeway. Other pollutants, such as NO and particle-bound polycyclic aromatic hydrocarbons, exhibited similar long-distance downwind concentration gradients. In contrast, air pollutant concentrations measured on the same route after sunrise, in the morning and afternoon, exhibited the typical daytime downwind decrease to background levels within ~300 m as found in earlier studies. Although pre-sunrise traffic volumes on the freeway were much lower than daytime congestion peaks, downwind UFP concentrations were significantly higher during pre-sunrise hours than during the daytime; UFP and NO concentrations were also strongly correlated with traffic counts on the freeway. We associate these elevated pre-sunrise concentrations over a wide area with a nocturnal surface temperature inversion, low wind speeds, and high relative humidity. Observation of a wide air pollutant impact area downwind of a major roadway prior to sunrise has important exposure assessment implications since it demonstrates extensive roadway impacts on residential areas during pre-sunrise hours, when most people are at home.
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影响因子：
10.4
作者：
McConnell R;Berhane K;Yao L;Jerrett M;Lurmann F;Gilliland F;Künzli N;Gauderman J;Avol E;Thomas D;Peters J
通讯作者：
Peters J
DOI：
10.3155/1047-3289.58.7.865
发表时间：
2008-07-01
影响因子：
2.7
作者：
Baldauf, Richard;Thoma, Eben;Bang, John
通讯作者：
Bang, John
影响因子：
5
作者：
Zhu, YF;Hinds, WC;Sioutas, C
通讯作者：
Sioutas, C
影响因子：
5
作者：
Kozawa, Kathleen H.;Fruin, Scott A.;Winer, Arthur M.
通讯作者：
Winer, Arthur M.
影响因子：
5
作者：
Khlystov, Andrey;Ma, Yilin
通讯作者：
Ma, Yilin