https://scholars.lib.ntu.edu.tw/handle/123456789/606319
Title: | The contribution of transport and chemical processes on coastal ozone and emission control strategies to reduce ozone | Authors: | Lien J HUI-MING HUNG |
Keywords: | Leighton ratio;Ozone;Ozone isopleth;Photochemistry;Sea breeze | Issue Date: | 2021 | Journal Volume: | 7 | Journal Issue: | 10 | Source: | Heliyon | Abstract: | The interaction between transport and chemistry is pivotal for local ozone (O3) concentration, especially for a coastal region where the upstream sources might change diurnally. In the current emission control policy, most pollutants, such as particulate matter, SO2, NOx, and CO, decrease while the annual O3 trend might increase due to the complex feedbacks of precursors. In this study, we investigate the influence of transport upon the wintertime O3 diurnal trend over ZuoYing Kaohsiung, an urban coastal site in southern Taiwan, by constructing a two-dimensional numerical model coupling both physical mechanisms and core chemical processes and provide a feasible emission control strategy. The transport process (i.e., import vs. export) for the daytime is determined using the Leighton Ratio (Φ), the ratio of O3-production over O3-loss rate, under the pseudo-steady-state condition. Φ shows a deviation of -9 to +13% from the photo-stationary state, and experiences a transition from import effect before 10:15 to weakening import or net export effect afterward associated with a net O3 production as sea breeze starts developing. The significantly higher Φ derived from observation than from simulation by a factor of 1.35 might be resulted from the over-reported NO2 due to NOy contribution on the NO2 measurement, and the influence of aerosol and cloud possibly reducing ~30% on applied NO2 photolysis rate constant, associated with aerosol optical depth of 0.75 ± 0.15 and single scattering albedo of 0.85 ± 0.15. In this studied NOxsaturated regime, the addition of sea breeze convergence over the land enhances the maximal O3 by ~10%, mainly due to the O3 accumulation (~88%). Furthermore, the ozone isopleth analysis as a function of nonmethane hydrocarbons and NOx emissions provides an achievable strategy to decrease both maximum daily ozone and the increment of ozone from morning to maximum by reducing hydrocarbons and NOx emissions, which can also eliminate the additional nitrate contribution on the aerosols ? 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/bync-nd/4.0/) |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85120897540&doi=10.1016%2fj.heliyon.2021.e08210&partnerID=40&md5=446cce6e40eefe61b98a61d6e4f4e232 https://scholars.lib.ntu.edu.tw/handle/123456789/606319 |
ISSN: | 24058440 | DOI: | 10.1016/j.heliyon.2021.e08210 |
Appears in Collections: | 大氣科學系 |
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