Applicability Study of Atmospheric Circulation and Ventilation Indices to Analysis of PM2.5 Episode in March 2018 br

초록

Recirculation factor(RF), ventilation index(VI), and stable energy(SE) of the atmosphere are the indices that could quantify the kinematic ability of the atmosphere. To verify the relationship of RF, VI, and SE with PM2.5 and its components, this study analyzed the measurement data on Air Pollution Monitoring Supersite in March 2018, when the calm wind condition was prevailingly observed. In this study, the period of PM2.5 episode was selected from 06 KST on March 24thto 13 KST on March 26th, 2018. Since March 25th, the PM2.5 concentration remained at most 100 mu g/m3. At that time, the RF continuously decreased and showed the lowest value(0.56) at 06 KST on March 26th. The correlation coefficients of PM2.5 and its components(SO42-, NO3-, NH4+, OC, EC) concentrations with meteorological factors(air temperature, relative humidity, wind speed, and planetary boundary layer height(PBLH)) and atmospheric indices during this episode were the highest among the entire period in March 2018, particularly for SE. When the SE was greater than 40J/cm2, the VI was smaller than 2,000m2/s, and the RF was smaller than 0.8, the PM2.5 concentration during this episode was shown to be relatively high. In conclusion, the circulation and ventilation indices could be alternative ways to explain the PM2.5 episode, compared to well-known meteorological factors in case of regional atmospheric stagnation

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