The international journal of Aerosol and Air Quality Research (AAQR) covers all aspects of aerosol science and technology, atmospheric science and air quality related issues.

To understand the carbon cycle at policy-relevant spatial scales, a high density of high-quality CO ₂ measurement sites is needed. In 2012, the Korea Meteorological Administration (KMA) installed CO ₂ monitoring systems at Anmyeondo (AMY) in the west, Jejudo Gosan Suwolbong (JGS) in the southwest, and Ulleungdo (ULD) in the east of South Korea. Three stations were instrumented with identical greenhouse gas measurement systems based on cavity ring-down spectroscopy (CRDS) and a new drying system developed by KMA and the Korea Research Institute of Standards and Science (KRISS). This drying system is suitable in humid areas; water vapor measured using CRDS in ambient air was 0.001 % to 0.004 % across the stations. Measurement uncertainties expressed by the quadrature sum of the uncertainties from the drying system, scale propagations, repeatability, and reproducibility were ∼0.11 ppm from all KMA stations in the 68 % confidence interval. Average monthly CO ₂ enhancements above the local background at each station were 4.3±3.3 ppm at AMY, 1.7±1.3 ppm at JGS, and 1±1.9 ppm (1 σ ) at ULD, respectively, during 2012 to 2016. At AMY station, located between China and South Korea, CO ₂ annual means and seasonal variations are also greater than the other KMA stations, indicating that it is affected not only by local vegetation, but also added anthropogenic sources. Selected baseline CO ₂ at AMY and at JGS in the west of South Korea is more sensitive to East Asia (e.g., China) according to wind direction and speed. Through the comparison of long-term trends and growth rates at AMY with other East Asian stations over 15 years, it was suggested that they could be affected not only by local vegetation but also by measurement quality.

Weekly rain samples were collected in coastal areas of the Shihwa Basin (Korea) from June 2000 to November 2007. The study region includes industrial, rural, and agricultural areas. Wet precipitation was analyzed for conductivity, pH, Cl⁻, NO₃⁻, SO₄²⁻, Na⁺, K⁺, Mg²⁺, NH₄⁺, and Ca²⁺. The major components of precipitation in the Shihwa Basin were NH₄⁺, volume-weighted mean (VWM) of 44.6 µeq∙L⁻¹, representing 43% of all cations, and SO₄²⁻, with the highest concentration among the anions (55%) at all stations. The pH ranged from 3.4 to 7.7 with a VMM of 4.84. H⁺ was weakly but positively correlated with SO₄²⁻ (r = 0.39, p < 0.001) and NO₃⁻ (r = 0.38, p < 0.001). About 66% of the acidity was neutralized by NH₄⁺ and Ca²⁺. The Cl⁻/Na⁺ ratio of the precipitation was 37% higher than seawater Cl⁻/Na⁺. The high SO₄²⁻/NO₃⁻ ratio of 2.3 is attributed to the influence of the surrounding industrial sources. Results from positive matrix factorization showed that the precipitation chemistry in Shihwa Basin was influenced by secondary nitrate and sulfate (41% ± 1.1%), followed by sea salt and Asian dust, contributing 23% ± 3.9% and 17% ± 0.2%, respectively. In this study, the annual trends of SO₄²⁻ and NO₃⁻ (p < 0.05) increased, different from the trends in some locations, due to the influence of the expanding power generating facilities located in the upwind area. The increasing trends of SO₄²⁻ and NO₃⁻ in the study region have important implications for reducing air pollution in accordance with national energy policy.

The international journal of Aerosol and Air Quality Research (AAQR) covers all aspects of aerosol science and technology, atmospheric science and air quality related issues.

To understand the Korean Peninsula's carbon dioxide (CO ₂ ) emissions and sinks as well as those of the surrounding region, we used 70 flask-air samples collected during May 2014 to August 2016 at Anmyeondo (AMY; 36.53 ^∘ N, 126.32 ^∘ E; 46 m a.s.l.) World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) station, located on the west coast of South Korea, for analysis of observed ¹⁴ C in atmospheric CO ₂ as a tracer of fossil fuel CO ₂ contribution ( C _ff ). Observed ¹⁴ C ∕ C ratios in CO ₂ (reported as Δ values) at AMY varied from −59.5 ‰ to 23.1 ‰, with a measurement uncertainty of ±1.8 ‰. The derived mean value C _ff of (9.7±7.8) µmol mol ⁻¹ (1 σ ) is greater than that found in earlier observations from Tae-Ahn Peninsula (TAP; 36.73 ^∘ N, 126.13 ^∘ E; 20 m a.s.l., 28 km away from AMY) of (4.4±5.7) µmol mol ⁻¹ from 2004 to 2010. The enhancement above background mole fractions of sulfur hexafluoride (Δ x (SF ₆ )) and carbon monoxide (Δ x (CO)) correlate strongly with C _ff ( r >0.7) and appear to be good proxies for fossil fuel CO ₂ at regional and continental scales. Samples originating from the Asian continent had greater Δ x (CO) : C _ff ( R _CO ) values, (29±8) to (36±2) nmol µmol ⁻¹ , than in Korean Peninsula local air ((8±2) nmol µmol ⁻¹ ). Air masses originating in China showed (1.6±0.4) to (2.0±0.1) times greater R _CO than a bottom-up inventory, suggesting that China's CO emissions are underestimated in the inventory, while observed R _SF6 values are 2–3 times greater than inventories for both China and South Korea. However, R _CO values derived from both inventories and observations have decreased relative to previous studies, indicating that combustion efficiency is increasing in both China and South Korea.