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Abstract:
In March 2012 the emissions of NO2 and SO2 from a power station located on the east side of Montevideo Bay (34 degrees 53' 10 '' S, 56 degrees 11' 49 '' W) were quantified by simultaneously using mobile and scanning multi-axis differential optical absorption spectroscopy (in the following mobile DOAS and scanning DOAS, respectively). The facility produces electricity by means of two technologies: internal combustion motors and steam generators. The motors are powered with centrifuged heavy oil and produce a maximum power of 80 MW approximately. The steam generators produce approximately 305 MW and are powered with heavy fuel oil. We compare the emissions obtained from the measured slant column densities (mobile DOAS and scanning DOAS) with the emissions estimated from fuel mass balance. On one occasion it was possible to distinguish between the two types of sources, observing two plumes with different SO2 and NO2 emission rates.
During the period of the campaign the mean SO2 emission flux was determined to be 0.36 (+/- 0.12) kg s(-1) and 0.26 (+/- 0.09) kg s(-1) retrieved from mobile and scanning DOAS respectively, while the calculated SO2 flux from the sulphur content of the fuel was 0.34 (+/- 0.03) kg s(-1). The average NO2 flux calculated from mobile DOAS was determined to be 11 (+/- 3) x 10(-3) kg s(-1). Using the scanning DOAS approach a mean NO2 flux of 5.4 (+/- 1.7) x 10(-3) kg s(-1) was obtained, which is significantly lower than by the mobile measurements. The differences between the results of mobile MAX-DOAS measurements and scanning DOAS measurements are most probably caused by the variability and the limited knowledge of the wind speed and direction. (C) 2014 Elsevier Ltd. All rights reserved.
