9:45 AM - 10:00 AM
[AAS04-19] Recent trends of NO2, VOC, and tropospheric ozone concentrations observed around Chiba, Japan in 2013-2018
Keywords:Nitrogen dioxide, Volatile organic compounds, Tropospheric ozone
Using the multi-axis differential optical absorption spectroscopy (MAX-DOAS), we conducted continuous observations of NO2, formaldehyde (HCHO; as a substitute for VOC) and O3 concentrations for altitudes of 0-1 km at the SKYNET Chiba site (35.63ºN, 140.10ºE, 21 m asl) for 6 years from 2013 to 2018. Analysis of the data showed that NO2 and HCHO concentrations decreased by about 30%, but a systematic decrease in O3 concentration was not observed. Similar trends were seen in tropospheric NO2 column data obtained by the Ozone Monitoring Instrument (OMI) onboard the Aura satellite of the National Aeronautics and Space Administration (NASA), and concentration data of NO2, non-methane hydrocarbon (NMHC; as a substitute for VOC), and photochemical oxidant (Ox; as a substitute for O3) observed by the atmospheric environmental regional observation system (AEROS) called Soramamekun. These results are consistent with previous reports. In this presentation, the observed trends and their causes will also be discussed by utilizing our unique MAX-DOAS system that was directed to 4 different azimuth directions (north, east, west, and south), while traffic is heavy at the north, a residential area is located at the east, there is a sea at the west, and a factory area is located at the south around the SKYNET Chiba site.