Theoretical implication of reversals of the ozone weekend effect systematically observed in Japan

Abstract

Abstract. Systematic changes of the ozone weekend effect are found over broad areas of Japan. These changes are characterized by (1) spatial reversals from a weekend increase in the vicinity of huge precursor source areas to a weekend decrease in the surrounding rural areas, and (2) temporal reversals from a weekend increase under relatively unsuitable meteorological conditions for ozone formation to a weekend decrease under relatively suitable conditions. We developed a simple numerical advection-reaction model to explain the relationship between the duration of advection and the supplied solar energy, which causes the daily maximum ozone concentration to be lower near the precursor source. Ozone isopleth diagrams for individual advection durations (equivalent to the distance from the source) for a wide range of initial precursor conditions show that both VOC-limited and NO x -limited regimes exist for each advection duration, but the area of NO x -limited regime becomes dominant as the advection duration increases because of the increased exposure of the air mass to solar energy. For given initial VOC and NO x concentrations, the area remote from the source becomes a NO x -limited regime even if the precursor source area is in the VOC-limited regime. The rate of reduction of weekend emissions of NO x is larger than that of VOC, causing a weekend increase in ozone inside an area of VOClimited regime near the source, but a weekend decrease in remote areas with a NO x -limited regime. The boundary between these two ozone formation regimes depends on meteorological conditions: when sunlight intensity and temperature are relatively low, the change from a VOC-limited to a NO x -limited regime occurs at a point more remote from the source than when they are relatively high, which causes a prevailing ozone weekend increase over a wide geographical area on days with lower ozone potential. Therefore, obserCorrespondence to: A. Kannari (kannari.akiyoshi@circus.ocn.ne.jp) vations of ozone weekend changes can be interpreted in light of the theoretical implications of our model; they can be used for determination of ozone formation regimes, which change in different locations and under different meteorological conditions.

Review on Atmospheric Ozone Pollution in China: Formation, Spatiotemporal Distribution, Precursors and Affecting Factors

“…On the urban scale, the weekend effect in the central area of the city was larger than that in the suburb, but on the local scale, the weekend effect showed a downward trend, with an increase in urbanization. Weekend O 3 changes depend on the intensity of the sunshine and the ratio of VOCs to NOx emissions [94].…”

Detectability assessment of a satellite sensor for lower tropospheric ozone responses to its precursors emission changes in East Asian summer

“…In 2010s, the Chinese anthropogenic emissions such as NO x and SO 2 began to decrease and this trend was well observed by satellites 6–9 . However, because the reduction of NO x emissions increased photochemical production of O 3 near the emission source regions (VOC-limited regions) 10 , it is not necessary that the lower tropospheric O 3 in China and East Asia have started to decrease, associated with the decrease in NO x emission in China, Korea, and Japan. Also the local/regional emission reduction may not decrease local/regional O 3 concentrations, because the trans-boundary to hemispheric transport contributes to raise the background level of the surface and the lower tropospheric O 3 concentrations 11 .…”

Potential Impact of Battery Electric Vehicle Penetration and Changes in Upstream Process Emissions Assuming Night‐Charging on Summer O3 Concentrations in Japan

“…Therefore, the positive and negative O 3 sensitivities enclosed with solid lines in Figure 6b are consistent with this trend. However, it has been reported that the distribution of regime boundary changes temporally and spatially (e.g., Kannari & Ohara, 2010; Lei et al., 2007; Martill et al., 2002; Sillman, 1999; Song et al., 2010). As a result, there are cases where O 3 has negative sensitivity (i.e., VOC‐limited) despite living in a suburban area (area enclosed with a dashed line in Figure 6b).…”