Revista Boliviana de Física
versión impresa ISSN 1562-3823
TAPIA PORTUGAL, Wilmer y ANDRADE, Marcos. CHARACTERIZING SURFACE OZONE CONCENTRATION IN THE CITY OF LA PAZ DURING EARLY MORNING REGIME. Revista Boliviana de Física [online]. 2011, vol.18, n.18, pp. 26-36. ISSN 1562-3823.
Sz The behavior of surface ozone was studied in the city of La Paz (3630 masl, 16° 29′52"S 68° 08′01"W). Measurements were obtained in downtown between 0:00 and 6:00 a.m. which was defined as the early morning regime. The reason for choosing such period for this is study is related to the existence of an anomalous peak around 3 am which was present in most measurements through the year. Independent measurements carried out at the outskirts of the city did not show this peak. Data from 2007 to 2010 were used for this study. The analysis of surface ozone, nitrogen monoxide, carbon monoxide and associated meteorological data suggests that the peak is a result of surface ozone produced during the previous day in downtown La Paz and transported later to the upper part of the city by the valley winds. The air mass containing this polluted air would be trapped in this region and brought it back to the city early in the morning of the following day. The typical behavior of the anomalous ozone peak shows a strong anticorrelation between surface ozone and nitrogen monoxide. On the other hand, measurements of vehicular traffic early in the morning clearly show a positive correlation with NO concentration suggesting that the observed reduction of the ozone peak during the weekends is related to the increase of vehicular traffic on that period.
Palabras llave : Land/atmosphere interactions; atmospheric chemistry; air quality and air pollution.