Measurements of formaldehyde at the U.S.-Mexico border during the Cal-Mex 2010 air quality study

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• 作者：Jun Zheng^a ; ^b ; Renyi Zhang^b ; ^{Renyi-Zhang@geos.tamu.edu} ; ^{renyi-zhang@tamu.edu} ; Jessica P. Garzó ; n^b ; ^c ; Marí ; a E. Huertas^b ; ^c ; Misti Levy^b ; Yan Ma^a ; Ricardo Torres-Jardó ; n^d ; Luis G. Ruiz-Suá ; rez^d ; Lynn Russell^e ; Satoshi Takahama^e ; Haobo Tan^f ; Guohui Li^g ; L.T. Molina^g
• 关键词：Formaldehyde ; PTR-MS ; Ozone ; Hydroxyl radical ; Secondary organic aerosol ; Air pollution
• 刊名：Atmospheric Environment
• 出版年：2013
• 出版时间：May, 2013
• 年：2013
• 卷：70
• 期：Complete
• 页码：513-520
• 全文大小：1081 K

文摘

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?¡À?2.6?ppbv occurred around 10?AM and a minimum of 2.8?¡À?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?¡À?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.