| Autor: |
Zheng, Jun1,2, Zhang, Renyi2 renyi-zhang@tamu.edu, Garzón, Jessica P.2,3, Huertas, María E.2,3, Levy, Misti2, Ma, Yan1, Torres-Jardón, Ricardo4, Ruiz-Suárez, Luis G.4, Russell, Lynn5, Takahama, Satoshi5, Tan, Haobo6, Li, Guohui7, Molina, L.T.7 |
| Předmět: |
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| Zdroj: |
Atmospheric Environment. May2013, Vol. 70, p513-520. 8p. |
| Abstrakt: |
Abstract: Ambient formaldehyde (HCHO), along with other volatile organic compounds (VOCs), was measured using proton-transfer reaction mass spectrometry (PTR-MS) at a ground site along the U.S.–Mexico border during the Cal-Mex 2010 air quality study. During the observation period, the HCHO mixing ratio varied between 1.0 ppbv and 13.7 ppbv. On average, a daily maximum of 6.3 ± 2.6 ppbv occurred around 10 AM and a minimum of 2.8 ± 1.3 ppbv was observed around midnight. The early onset of the HCHO daily maximum (∼ 3 h before the solar noon) indicated the presence of primary HCHO sources and a fast photolysis loss of HCHO, consistent with a measured low ratio of HCHO to acetaldehyde of (2.5 ± 0.8). Using the simulated photolysis rates, we estimated the contribution of OH radical production from HCHO photolysis relative to that from O3 photolysis, with a ratio from 0.8 to 18 and the highest values around traffic rush hours. Hence, our results indicate that HCHO plays a dominant role in regulating the OH radical budget in the area. [Copyright &y& Elsevier] |
| Databáze: |
GreenFILE |
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