Anguang's new progress in the observation of HCHO in MAX-DOAS

[ Instrument Network Instrument Development ] Recently, An Guangxue Xie Pinhua Researcher Group has made new progress in the observation of HCHO in MAX-DOAS. The related research work is to observe the tropospheric HCHO VCD and CAMS based on the MAX-DOAS of Beijing suburbs during the APEC 2014. Ground-based MAX-DOAS observations of tropospheric formaldehyde VCDs and comparisons with the CAMS model at a rural site near Beijing during APEC 2014 was published in the international academic journal atmospheric chemistry and physics.

HCHO plays an important role in atmospheric photooxidation. As a reactive gas, HCHO photolysis produces HO2 radicals; HO2 reacts rapidly with NO to form OH radicals, which affects the oxidizing power of the atmosphere. Sources of tropospheric formaldehyde mainly include direct emissions and secondary generation. In addition to anthropogenic emissions, a small portion of HCHO is directly emitted from vegetation. Therefore, the study of HCHO is of great significance for the study of OH radicals and the formation of secondary organic aerosols. The 2014 APEC meeting was held in Huairou District, Beijing. In order to improve air quality during APEC, the Beijing-Tianjin-Hebei and surrounding areas implemented the “APEC Conference Air Quality Assurance Policy”, and Beijing implemented different levels of emission reduction measures in the surrounding areas. The APEC Summit provides an opportunity to study the relationship between environmental quality and pollutant emissions.

The research team cooperated with Max Planck Institute of Chemistry in Germany to study the source of Huairou HCHO and its relationship with emission control measures and meteorological conditions through MAX-DOAS observation. The HCHO concentration level and daily variation characteristics were determined. The relationship between HCHO concentration changes and regional transmission and local emissions in pollution events was studied in combination with meteorological conditions, mainly from pollution transmission in the southern region and photochemical volatile organic compounds (VOCs) reactions. The secondary source produced; quantified the change of HCHO concentration before and after APEC during APEC, HCHO VCD decreased by ~38%±20% and ~30%±24% compared with before and after APEC, and analyzed the factors causing the decrease of HCHO concentration during APEC . The researchers also compared the CAMS (Copernicus Atmosphere Monitoring Service) model of the European Mesoscale Weather Forecasting Center, and discussed the reasons for the consistency and difference between the CAMS model and the MAX-DOAS measurement. The correlation coefficient R2 is greater than 0.68, but The CAMS model systematically underestimated the low concentration of HCHO. This study assesses the effectiveness of photochemical pollution control measures taken during the APEC Summit. In addition, the study provides a scientific basis for future development of pollution control measures and supports validation model simulation.

The research work was funded by projects such as the National Natural Science Foundation of China.

(Original title: Anguang's new progress in the observation of HCHO in MAX-DOAS)