Detection of pollution transport events southeast of Mexico City using ground-based visible spectroscopy measurements of nitrogen dioxide 1Centro de Ciencias de la Atmósfera, Univ. Nacional Autónoma de México, México D.F., México
2Institute for Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Forschungszentrum Karlsruhe GmbH, Garmisch-Partenkirchen, Germany
Received: 19 Dec 2008 – Published in Atmos. Chem. Phys. Discuss.: 24 Feb 2009 Abstract. This work presents ground based differential optical absorption spectroscopy (DOAS)
measurements of nitrogen dioxide (NO2) during the MILAGRO field campaign in March 2006
at the Tenango del Aire research site located to the southeast of Mexico City.
The DOAS NO2 column density measurements are used in conjunction with ceilometer,
meteorological and surface nitric oxide (NO), nitrogen oxides (NOx)
and total reactive nitrogen (NOy) measurements to analyze pollution transport
events to the southeast of Mexico City during the MILARGO field campaign.
The study divides the data set into three case study pollution transport events
that occurred at the Tenango del Aire research site.
The unique data set is then used to provide an in depth analysis of
example days of each of the pollution transport events. An in depth analysis
of 13 March 2006, a Case One day, shows the transport of several air pollution
plumes during the morning through the Tenango del Aire research site when
southerly winds are present and demonstrates how DOAS tropospheric NO2 vertical
column densities (VCD), surface NO2 mixing ratios and ceilometer data are used
to determine the vertical homogeneity of the pollution layer. The analysis of
18 March 2006, a Case Two day, shows that when northerly winds are present for
the entire day, the air at the Tenango del Aire research site is relatively
clean and no major pollution plumes are detected. Case 3 days are characterized
by relatively clean air throughout the morning with large DOAS NO2 enhancements
detected in the afternoon. The analysis of 28 March 2006 show the DOAS NO2
enhancements are likely due to lightning activity and demonstrate how suitable
ground-based DOAS measruements are for monitoring anthropogenic and natural
pollution sources that reside above the mixing layer.
Revised: 09 Jun 2009 – Accepted: 07 Jul 2009 – Published: 22 Jul 2009
Citation: Melamed, M. L., Basaldud, R., Steinbrecher, R., Emeis, S., Ruíz-Suárez, L. G., and Grutter, M.: Detection of pollution transport events southeast of Mexico City using ground-based visible spectroscopy measurements of nitrogen dioxide, Atmos. Chem. Phys., 9, 4827-4840, doi:10.5194/acp-9-4827-2009, 2009.