不同传输通道下珠江三角洲臭氧与前体物非线性响应关系

高度城市化的珠三角地区臭氧污染频发,臭氧污染的非线性、区域性以及气象过程影响使臭氧精确防控面临巨大挑战.本研究利用臭氧源解析技术OSAT,分析不同传输通道下珠三角臭氧敏感区分布差异,量化城市间的臭氧传输贡献,并通过敏感性试验,探讨珠三角及典型城市的臭氧污染控制策略.结果表明,静风条件下,VOCs敏感区集中在珠三角中部城...

Nonlinear Response Relationship Between Ozone and Precursor Emissions in the Pearl River Delta Region Under Different Transmission Channels

With the rapid development of urbanization, ozone (O₃) pollution is an ongoing occurrence in the Pearl River Delta (PRD) region in China. The effective control of O₃ pollution is a great challenge owing to the nonlinear relationship between O₃ and precursor emissions and the effect of meteorological conditions. Based on the regional air quality model CAMx-OSAT (ozone source apportionment technology), O₃ formation regimes were determined, and inter-city transportation across PRD was quantified under different transmission channels. The results showed that spatial differences were observed for the O₃ formation regimes under different transmission channels. The VOCs-sensitive regime was mainly located in the central areas of the PRD region, and the NO_x-sensitive regime was distributed in the suburban areas of the PRD regions under calm wind conditions. When the northeast wind was prevailing, the polluted air mass of the urban agglomeration was transmitted southwesterly downward, resulting in the downwind areas being transformed to VOCs-sensitive; the upwind areas were still NO_x-sensitive. Under the southeast wind, the VOCs-sensitive regime had a banding distribution along the southeast-northwest direction, and the remaining areas were NO_x-sensitive. With the influence of transmission channels, downwind cities were significantly affected by the transmission of upwind urban agglomerations (41%-87%), whereas the local formation was the main contributor under the calm wind conditions (60%-87%). To explore the relationship between O₃ and precursor emissions, a series of sensitivity tests were designed. The results showed that maximized areas (20%-36%) with reductions in O₃ can be achieved by reducing VOCs and NO_x in the corresponding sensitive regimes, and the maximized level with the reduction in O₃ can be fulfilled by reducing VOCs in the VOCs-sensitive regime. For the typical city Jiangmen, the area that met the standard increased the most under the calm wind (11%) and southeast wind (8%) conditions when VOCs and NO_x were reduced in the corresponding sensitive regimes. Additionally, under northeast wind conditions, reducing VOCs in the VOCs-sensitive regime can more effectively control O₃, as the area up to the standard increased by 140%.