Significant increase of surface ozone at a rural site, north of eastern China

Xiaobin Xu,Weijun Quan,Ziyin Zhang,Weili Lin,Jing Xu,Zhiqiang Ma

doi:10.5194/acp-16-3969-2016

Xiaobin Xu, Weijun Quan + Show 4 more

Open Access

https://doi.org/10.5194/acp-16-3969-2016

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Abstract

Abstract. Ozone pollution in eastern China has become one of the top environmental issues. Quantifying the temporal trend of surface ozone helps to assess the impacts of the anthropogenic precursor reductions and the likely effects of emission control strategies implemented. In this paper, ozone data collected at the Shangdianzi (SDZ) regional atmospheric background station from 2003 to 2015 are presented and analyzed to obtain the variation in the trend of surface ozone in the most polluted region of China, north of eastern China or the North China Plain. A modified Kolmogorov–Zurbenko (KZ) filter method was performed on the maximum daily average 8 h (MDA8) concentrations of ozone to separate the contributions of different factors from the variation of surface ozone and remove the influence of meteorological fluctuations on surface ozone. Results reveal that the short-term, seasonal and long-term components of ozone account for 36.4, 57.6 and 2.2 % of the total variance, respectively. The long-term trend indicates that the MDA8 has undergone a significant increase in the period of 2003–2015, with an average rate of 1.13 ± 0.01 ppb year−1 (R2 = 0.92). It is found that meteorological factors did not significantly influence the long-term variation of ozone and the increase may be completely attributed to changes in emissions. Furthermore, there is no significant correlation between the long-term O3 and NO2 trends. This study suggests that emission changes in VOCs might have played a more important role in the observed increase of surface ozone at SDZ.

Highlights

Tropospheric ozone (O3) plays a key role in the oxidizing capacity of the atmosphere (Penkett, 1988) and acts as a greenhouse gas in terms of radiative forcing at the Earth’s surface (IPCC, 2013)
We separated the time series of maximum daily average 8 h (MDA8) concentration of surface O3 observed at SDZ in the period of 2003–2015 into various spectral components using a modified Kolmogorov– Zurbenko (KZ) filter
This separation has led to a better understanding of the variation of surface O3 at the site and its relationships with the meteorological and precursor variables, enabling us to unravel the trend of O3 from the original data containing noises and seasonality, and to estimate the contribution of changes of precursor emissions to the trend

Summary

Introduction

Tropospheric ozone (O3) plays a key role in the oxidizing capacity of the atmosphere (Penkett, 1988) and acts as a greenhouse gas in terms of radiative forcing at the Earth’s surface (IPCC, 2013). It is an important precursor of the OH radical, changes in its abundance can exert indirect radiative forcing by altering the lifetimes of some other greenhouse gases. Observations (Oltmans et al, 2006) and model simulations (Hauglustaine and Brasseur, 2003) indicate that ground-level O3 increased distinctly at northern mid-latitudes during the latter half of the 20th century, which is qualitatively in agreement with the increasing anthropogenic emissions of precursors.

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