Spatial Distribution of Ozone Formation in China Derived from Emissions of Speciated Volatile Organic Compounds

Ozone
(O3) pollution is becoming increasingly severe
in China. In addition, our limited understanding of the relationship
between O3 and volatile organic compounds (VOCs), is an
obstacle to improving air quality. By developing an improved source-oriented
speciated VOC emission inventory in 2013, we estimated the ozone formation
potential (OFP) and investigated its characteristics in China. Besides,
a comparison was made between our estimates and space-based observations
from the ozone monitoring instrument (OMI) on the National Aeronautics
and Space Administration (NASA)’s Aura satellite. According
to our estimates, m-/p-xylene, ethylene, formaldehyde,
toluene, and propene were the five species that had the largest potential
to form ozone, and on-road vehicles, industrial processes, biofuel
combustion, and surface coating were the key contributing sectors.
Among different regions of China, the North China Plain, Yangtze River
Delta, and Pearl River Delta had the highest OFP values. Our results
suggest that O3 formation is VOC-limited in major urban
areas of China. Additionally, considering the different photochemical
reactivities of various VOC species and the disparate energy and industry
structures in the different regions of China, more efficient OFP-based
and localized VOC control measures should be implemented, instead
of the current mass-based and nationally uniform policies.

臭氧（O₃）污染在中国日趋严峻。此外，当前我们对臭氧与挥发性有机物（VOCs）之间相互关系的认知不足，是制约空气质量改善的一大障碍。本研究通过构建2013年优化后的源导向分物种VOC排放清单，估算了中国区域的臭氧生成潜势（OFP）并分析其特征；同时将估算结果与搭载于美国国家航空航天局（NASA）Aura卫星的臭氧监测仪器（OMI）获取的天基观测数据进行了对比。估算结果显示，间/对二甲苯、乙烯、甲醛、甲苯与丙烯是臭氧生成潜势最高的5种VOC物种；道路移动源、工业过程、生物燃料燃烧以及表面涂装行业是贡献臭氧生成潜势的关键排放源。在中国不同区域中，华北平原、长江三角洲与珠江三角洲的臭氧生成潜势最高。本研究结果表明，中国主要城市区域的臭氧生成受VOCs限制。此外，考虑到不同VOC物种的光化学反应活性存在差异，且中国各区域的能源与产业结构各不相同，当前采用的基于质量浓度的全国统一管控政策亟待优化，应推行更高效的、基于臭氧生成潜势的区域化VOC管控措施。