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Seasonal and regional variations of atmospheric ammonia across the South Korean Peninsula
이태형,최진수,박태현,Rahul Singh,반지희,김경훈,박규태,강석원,최시영,송정인,유동길,배민석,안준영,정해진,임용재,김현웅,황태경,최유진,김수영,김효선,장유운,신혜정,임윤성,이종태,박진수 한국대기환경학회 2023 Asian Journal of Atmospheric Environment (AJAE) Vol.17 No.1
This study aimed to identify the factors causing NH3 emissions in the South Korean Peninsula and West Sea region. To analyze the trends of NH3 and other air pollutants, such as NOx, CO, and NR-PM1, we collected samples from six supersites across the peninsula, a roadside in Seoul, and the West Sea over different sampling periods, ranging from 1 month to 1 year. The highest NH3 concentrations were found at rural areas, ascribed to agricultural activities, particularly NH4NO3 decomposition at high summer temperatures. Areas with low population densities recorded the lowest NH3 concentrations, attributed to the lack of anthropogenic activities. A roadside field experiment confirmed the close link between ambient NH3 and vehicle emissions in urban regions by showing a strong correlation between CO and NOx concentrations and that of NH3. Moreover, we examined oceanic emissions near the eastern coast of South Korea in the West Sea. Long-range transportation studies confirmed that most of the pollutants ( NH3, CO, and PM1) were transported by wind from the northeastern region of China. A maritime origin study showed that oceanic emissions and NH4NO3 decomposition in the atmosphere owing to high temperatures were the causing NH3 pollution. These findings provided valuable insights into the emission sources of NH3 in primary air pollutants in South Korea, highlighting the contributions of land-based and oceanic sources. Our study can help inform policymakers and stakeholders for developing effective regional air pollution control strategies.
이태형,황지현,강석원,김경훈,박태현,반지희,송정인,박인선,신혜정,정해진,강공언,배민석,이권호 한국대기환경학회 2023 한국대기환경학회지 Vol.39 No.2
Nitric acid (HNO3) is formed to ammonium nitrate (NH4NO3) of secondary aerosols by the photochemical reaction. A semi-continuous HNO3 measurement system was developed for the concentration of HNO3 in the atmosphere through ion chromatography after it is sufficiently absorbed by deionized water. In order to correct the Nitrate (NO3 -) concentration, an experiment was conducted to simulate the concentration of atmospheric nitrogen dioxide (NO2) and hydrogen peroxide (H2O2) which produce additional NO3 -. To evaluate the performance of the instrument, it compared the denuder method, Vocus PTR-TOF (Vocus proton-transfer-reaction time-of-flight mass spectrometer), and semi-continuous HNO3 measurement systems at high concentrations of HNO3 using a standard gas. In addition, an experiment to measure HNO3 in the atmosphere was conducted using both the denuder method and the semi-continuous HNO3 system. The concentration of HNO3 additionally generated by H2O2 and NO2 inside the measurement system was measured lower than the detection limit of the previously performed QC/QA, indicating that it was suitable for measuring HNO3. In the comparison experiment between the different equipment using a standard HNO3 gas, a difference of 4.7% to 8.4% was observed, demonstrating that the results of HNO3 concentration measurements were similar. When measuring HNO3 in the air, the comparison experiment between the semi-continuous HNO3 system and the denuder method showed a high correlation with a coefficient of about 0.98 and a difference of only 0.2%. The semi-continuous HNO3 measuring system was found to be hardly impacted by interference from other materials in the sample and produced results that were similar measured values to using other equipment. Also, it is easy to analyze the concentration and chemical properties of HNO3 during the measurement period because the data is acquired in real-time.