Meteorology influencing springtime air quality, pollution transport, and visibility in Korea

Md Firoz Khan,Ralph E. Kuehn,Edward J. Hyer,Christoph Knote,James H. Crawford,Detlev Helmig,Carolyn E. Jordan,Edwin Eloranta,Barry L. Lefer,Sang-Ok Han,David A. Peterson,Rokjin J. Park,Robert Holz

doi:10.1525/elementa.395

Abstract

In an environment with many local, remote, persistent, and episodic sources of pollution, meteorology is the primary factor that drives periods of unhealthy air quality and reduced visibility. The 2016 Korea-United States Air Quality (KORUS-AQ) field study provides a unique opportunity to examine the impact of meteorology on the relative influence of local and transboundary pollution. Much of the KORUS-AQ campaign can be grouped into four distinct research periods based on observed synoptic meteorology, including a period of complex aerosol vertical profiles driven by dynamic meteorology, stagnation under a persistent anticyclone, low-level transport and haze development, and a blocking pattern. These episodes are examined using a diverse archive of ground, airborne, and satellite data. While frontal boundaries are recognized as the primary mechanism driving pollution transport in eastern Asia, results show that they are not always related to sustained periods of hazardous air quality and reduced visibility at the surface. Significant long-range transport of pollution and dust was constrained to a few short events, suggesting that the majority of pollutants sampled during KORUS-AQ originated from local sources. A severe regional pollution episode is examined in detail, featuring dense haze and significant secondary particle formation within a shallow moist boundary layer. Observations during KORUS-AQ also highlight a rapid, 40 ppbv increase in ozone pollution as a strong sea breeze front traversed the Seoul Metropolitan Area. Representativeness of meteorology and pollution conditions measured by KORUS-AQ is considered by comparison with climatology. This analysis is an essential step toward improved local and regional forecasting of air quality and visibility.

Highlights

Air quality is a growing environmental concern in many regions across the globe
Understanding the factors contributing to poor air quality in this region was the primary objective of the Korea-United States Air Quality (KORUS-AQ) field study during May–June 2016
The broad scope of KORUS-AQ provides an unprecedented opportunity for analysis of air quality and visibility hazards arising from the combination of local and transboundary pollution

Summary

Introduction

Air quality is a growing environmental concern in many regions across the globe. Increased populations, energy use, and industrial activity continue to generate pollutants that impact human health (e.g., Kampa and Castanas, 2008; Shang et al, 2013; Liao et al, 2017) and produceJeju-do, KR ‡ NASA Langley Research Center, Hampton, VA, US § School of Earth and Environmental Sciences, Seoul NationalUniversity, Seoul, KR ‖ Space Science and Engineering Center, University of Wisconsin, US ¶ Meteorological Institute, Department of Physics, LMU Munich, hazardous visibility conditions (e.g., Tao et al, 2012; Fu and Chen, 2017). Observations during the KORUS-AQ measurement period reveal that a specific synoptic environment is required for cold fronts to induce persistent air quality and visibility impacts at the surface.

Results

Conclusion