Does Light Pollution Affect Nighttime Ground-Level Ozone Concentrations?

Abstract

Ground-level ozone (O3) is mainly produced during daytime in the presence of ultraviolet (UV) light and later destroyed by nitrogen oxides during nighttime. However, light pollution caused by the excessive use of artificial lights may disrupt the chemistry of night-time ground-level O3 by providing enough energy to initiate nighttime ground-level O3 production. In this study, nighttime (7 p.m. to 7 a.m.) ground-level O3, nitrogen oxide (NO), and nitrogen dioxides (NO2) concentrations were observed for three years (2013, 2014, and 2015). The existence of O3 was found during nighttime, especially in urban areas with a concentration range of 8–20 ppb. The results suggested that nighttime variations of ground-level O3 concentrations were higher in urban areas than in suburban areas. The mean nighttime O3 concentration at urban sites varied, possibly because the distribution of anthropogenic lights around the urban sites is brighter than in suburban locations, as indicated by the data from the light-pollution map. This anthropogenic light has not caused the suspected nighttime photolysis processes, which directly slowed nighttime oxidation. The photochemistry rate of JNO2/k3 was supposed to be near zero because of the absence of photochemical reactions at night. However, the minimum concentration in all urban and suburban sites ranged from 2–3 ppb, indicating that O3 might also form at night, albeit not due to light pollution.

Drivers of nocturnal interactions between ground-level ozone and nitrogen dioxide

“…The box showed high variations in Klang, and Shah Alam compared to Putrajaya and Minden. The monthly nighttime variations in NOx were similar to other studies (Guttikunda & Gurjar, 2011;Awang et al, 2015;Shith et al, 2022), which attributed to the poor dependence of NOx on the meteorological situation. Less anthropogenic sources in sub-urban were related to the decrease of NO2 during nighttime.…”

“…This could be due to the location itself, as Minden was located in the university area, where highly illuminated for safety and security reasons for the students during nighttime. Similar observations have been recorded by Shith et al (2022) at Putrajaya, as its functions as the federal administrative centre in Malaysia. This place was busy during the daytime when people went to work and had fewer activities during the nighttime.…”

“…The high O3 concentrations in urban sites (Shah Alam) happened before the MCO was implemented. This is due to various anthropogenic activities which became a significant source of O3 precursors in urban areas (Ghazali et al, 2010;Latif et al, 2012;Awang et al, 2015;Shith et al, 2021;Shith et al, 2022). After the MCO, the O3 concentrations reduced significantly, indicating the reduction in motor vehicles on the road as the effect of the temporary closure of industries during the MCO 1 (Othman & Latif, 2020;Mohd Nadzir et al, 2021;Awang et al, 2022).…”

“…Recently, due to the high nighttime O3 concentration phenomenon in many regions, focused nighttime O3 pollution has been crucially observed and investigated (Sousa et al, 2011;Awang et al, 2015;Awang & Ramli, 2017;Shith & Ramli, 2019;Shith et al, 2021;Shith et al, 2022;Wang et al, 2022). Sousa et al (2011) found that meteorological factors are the factors that increased nighttime O3 concentrations in urban and suburban areas.…”

“…With the absence of sunlight during nighttime, the high nighttime concentrations are associated with the transport process and meteorological conditions (Kulkarni et al, 2013). Substantial research also argues that the possibility of light pollution in cities enhanced the O3 formation during nighttime (Stark et al, 2010;Brown et al, 2012;Shith et al, 2022).…”