Observations of SO₂ and NO₂ by mobile DOAS in the Guangzhou eastern area during the Asian Games 2010

Abstract. Mobile passive differential optical absorption spectroscopy measurements of SO₂ and NO₂ were performed in the Guangzhou eastern area (GEA) during the Guangzhou Asian Games 2010 from November 2010 to December 2010. The observations were carried out between 10:00 to 13:00 (local time, i.e., during daylight). Spatial and temporal distributions of SO₂ and NO₂ in this area were obtained and emission sources were determined using wind field data. The NO₂ vertical column densities were found to agree with Ozone Monitoring Instrument values. The correlation coefficient (referred to as R²) was 0.88 after cloud filtering within a specific ground pixel. During the Guangzhou Asian Games and Asian Paralympics (Para) Games, the SO₂ and NO_x emissions in the area were quantified using averaged wind speed and wind direction. For times outside the games the average SO₂ emission was estimated to be 9.50 ± 0.90 tons per hour and the average NO_x emission was estimated to be 5.87 ± 3.46 tons per hour. During the phases of the Asian and Asian Para Games, the SO₂ and NO_x emissions were reduced by 53.50% and 43.50%, respectively, compared to the usual condition. We also investigated the influence of GEA on Guangzhou University Town, the main venue located northwest of the GEA, and found that SO₂ concentrations here were about tripled by emissions from the GEA.