Apportioning and Locating Nonmethane Hydrocarbon Sources to a Background Site in Korea

Abstract

Nonmethane hydrocarbons (NMHCs) measured between April 2004 and March 2005 at a background monitoring site on Sukmo Island, Korea were analyzed to identify and apportion NMHC sources. A total of 7694 samples and 35 NMHC species were analyzed. Positive matrix factorization (PMF), applied to identify and apportion the sources of NMHCs, resolved six sources: two fuel evaporative sources (36.3%), solvent sources (25.4%), mixed sources of vehicle exhaust and combustion (22.8%), petrochemical sources (9.6%), and biogenic sources (5.4%). During the summer, the largest contributors to ozone formation were biogenic sources (48.9% and 79.7% by maximum incremental reactivity and propene-equivalent concentration, respectively), which were situated locally, and secondary sources included solvent sources (22.2% and 7.4%) and fuel evaporative sources (15.6% and 8.2%). For evaporative-1 sources composed of long-lived alkanes, the potential source contribution function (PSCF) technique using 48 h back trajectories revealed oil and gas fields in China as potential source areas of fresh "regional" air masses. In addition, the PSCF results for evaporative-2 sources and a long-lived marker species of vehicle exhaust/combustion sources showed that the NMHC mixing ratio in Sukmo, South Korea was enhanced by long-range transport from the Shandong area in China.

Comprehensive source apportionment of volatile organic compounds using observational data, two receptor models, and an emission inventory in Tokyo metropolitan area

“…Short‐lived NMHC species generally have large contributions to ozone production. The receptor models generally underestimate concentrations of short‐lived NMHC species; thus, contributions of short‐lived NMHC species to ozone formation are also underestimated [ Choi et al , 2010]. For the assessment of short‐lived species for ozone production, usage of a chemical transport model is effective [ Jin et al , 2008].…”

Toward resolving the budget discrepancy of ozone-depleting carbon tetrachloride (CCl<sub>4</sub>): an analysis of top-down emissions from China

“…Furthermore, given that China has been the largest producer and consumer of HCFCs since 2003, and that production of HCFC-22 accounts for more than 80 % of all Chinese HCFC production (UNEP, 2009), HCFC-22 is the best-suited reference compound for use with China. Additionally, strong Chinese HCFC-22 emissions have been determined from atmospheric observations and inverse modeling in previous studies Li et al, 2011;Stohl et al, 2010;An et al, 2012;Fang et al, 2012) Fang et al, 2014) and ranged from 89 Gg yr −1 in 2011 to 144 Gg yr −1 in 2015. The uncertainty in the top-down estimates was 30 %, which mainly related to an assumed uncertainty of ±50 % in annual prior emissions used for the inversion calculation (Fig.…”

“…We included all CCl 4 enhancement events observed at GSN, thereby representing a better characterization of emission sources throughout East Asia and not just in China. The PMF model has been widely used to identify and apportion sources of atmospheric pollutants (Guo et al, 2009;Lanz et al, 2009;Li et al, 2009;Choi et al, 2010) and is an optimization method that uses a weighted least squares regression to obtain a best fit to the measured concentration enhancements of chemical species (details in the text of the Supplement) and to resolve the number of source factors controlling the observations. A brief mathematical expression of the model is given by Eq.…”

“…Its emissive use, production and consumption are regulated under the Montreal Protocol on Substances that Deplete the Ozone Layer and its Amendments (MP). After reaching a peak in the early 1990s, the atmospheric abundance of CCl 4 has been decreasing at a rate of −4.9 ± 0.7 ppt Cl yr −1 (Carpenter et al, 2014) due to the phase-out of CCl 4 use in MP non-Article 5 (developed) countries by 1995. MP Article 5 (developing) countries, including China, were required to cease CCl 4 production and consumption for dispersive applications by 2010.…”

“…MP Article 5 (developing) countries, including China, were required to cease CCl 4 production and consumption for dispersive applications by 2010. However, CCl 4 production and consumption for non-dispersive use (e.g., as chemical feedstock and as a process agent) continues to be allowed, and thus CCl 4 is still produced and consumed alongside the increasing production of non-ODS chemicals (Carpenter et al, 2014). At present, the global bottom-up CCl 4 emissions derived from reporting countries are 3 (0-8) Gg yr −1 for 2007-2013 (Carpenter et al, 2014;Liang et al, 2016).…”