Remote sensing of atmospheric nitrogen dioxide in an urban area in central northern Mexico

Nitrogen dioxide (NO2) was remotely measured in the urban area of San Luis Potosí (México) using the differential optical absorption spectroscopy (DOAS) technique. Measurements were taken from July to August 2015. In this technique, light scattered by the sun through the atmosphere is focused by a telescope onto a linear array-based spectrometer at ground level. During the measurement period, the maximum NO2 levels (2.3 x 1016 molecules/cm2) were found at around 11:00 h, whereas NO2 levels fell on days with wind speeds lower than 1.5 m/s. The NO2 levels were compared and explained with the behavior of meteorological data such as wind speed, relative humidity, and surface temperature obtained from the Weather Research and Forecasting Model (WRF).