Seasonal influences on surface ozone variability in continental South Africa and implications for air quality

Author:

Laban Tracey Leah,van Zyl Pieter GideonORCID,Beukes Johan Paul,Vakkari Ville,Jaars Kerneels,Borduas-Dedekind NadineORCID,Josipovic Miroslav,Thompson Anne MeeORCID,Kulmala MarkkuORCID,Laakso Lauri

Abstract

Abstract. Although elevated surface ozone (O3) concentrations are observed in many areas within southern Africa, few studies have investigated the regional atmospheric chemistry and dominant atmospheric processes driving surface O3 formation in this region. Therefore, an assessment of comprehensive continuous surface O3 measurements performed at four sites in continental South Africa was conducted. The regional O3 problem was evident, with O3 concentrations regularly exceeding the South African air quality standard limit, while O3 levels were higher compared to other background sites in the Southern Hemisphere. The temporal O3 patterns observed at the four sites resembled typical trends for O3 in continental South Africa, with O3 concentrations peaking in late winter and early spring. Increased O3 concentrations in winter were indicative of increased emissions of O3 precursors from household combustion and other low-level sources, while a spring maximum observed at all the sites was attributed to increased regional biomass burning. Source area maps of O3 and CO indicated significantly higher O3 and CO concentrations associated with air masses passing over a region with increased seasonal open biomass burning, which indicated CO associated with open biomass burning as a major source of O3 in continental South Africa. A strong correlation between O3 on CO was observed, while O3 levels remained relatively constant or decreased with increasing NOx, which supports a VOC-limited regime. The instantaneous production rate of O3 calculated at Welgegund indicated that ∼40 % of O3 production occurred in the VOC-limited regime. The relationship between O3 and precursor species suggests that continental South Africa can be considered VOC limited, which can be attributed to high anthropogenic emissions of NOx in the interior of South Africa. The study indicated that the most effective emission control strategy to reduce O3 levels in continental South Africa should be CO and VOC reduction, mainly associated with household combustion and regional open biomass burning.

Publisher

Copernicus GmbH

Subject

Atmospheric Science

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3