人为和生物排放量对春季东亚地面臭氧的协同贡献

臭氧O3的生成是多因子影响的复杂非线性过程, 一个因子在其他因子起作用时的贡献可以分为纯贡献与协同贡献。本文采用因子分离方法和改进后的区域空气质量模式 (RAQM) 计算了人为氮氧化物 (NOx＝NO+NO2)、人为可挥发性有机化合物(AVOCs)以及生物可挥发性有机化合物(BVOCs)对春季东亚地区地面臭氧浓度的协同贡献及总贡献(＝纯贡献+协同贡献)。结果表明, AVOCs、BVOCs与NOx对O3生成量的贡献依赖于AVOCs、BVOCs排放量的相对大小。AVOCs或BVOCs排放量显著偏高的地区, 其总贡献主要来源于其与NOx的协同贡献。从区域角度 (1°×1°) 来看, BVOCs对东亚春季地面O3浓度的贡献较小, BVOCs排放量明显偏高的个别地区除外。BVOCs总贡献有很强的日变化特征, BVOCs总贡献有可能小于其协同贡献。个例研究的成果应用于O3调控对策的制定和实施很可能达不到预期的效果。我国北方 (30°N以北) 应控制人为源; 我国南方BVOCs排放量显著偏高的地区, 生物源和人为源的贡献都必须考虑。

Synergistic Impacts of Anthropogenic and Biogenic Emissions on Spring Surface Ozone in East Asia

The formation of ozone (O3) is a complex nonlinear process including several factors. The contribution of one factor consists of its pure contribution and synergistic interaction with other factors. The impacts due to anthropogenic volatile organic compounds (AVOCs) and biogenic volatile organic compounds (BVOCs) emissions on ozone concentrations are calculated by a numerical method named factor separation technique and the improved regional air quality model (RAQM). It is indicated that O3 formation depends significantly on the relative ratios of AVOCs to BVOCs. Most of the total contributions of AVOCs or BVOCs in the areas with elevated emissions of AVOCs or BVOCs are from synergistic contributions of AVOCs and NOx or BVOCs and NOx. BVOCs play a minor role in the surface O3 formation in most areas of East Asia except some areas with high emissions of BVOCs in spring. The total contribution of BVOCs has a remarkable daily variation and may be less than the synergistic contributions of BVOCs in some periods, depending on meteorological conditions and emissions. This suggests that O3 control measures from episodic studies may be not feasible in long-term (e.g., seasonal) O3 reductions. Anthropogenic emissions in the northern areas of China (north of 30°N) should be reduced whereas both anthropogenic and biological emissions in the southern areas with elevated emissions of BVOCs should be considered for O3 controls.