Morris Ralph, Koo Bonyoung, Yarwood Greg
ENVIRON International Corporation, Novato, CA 94945, USA.
J Air Waste Manag Assoc. 2005 Nov;55(11):1683-93. doi: 10.1080/10473289.2005.10464764.
Version 4.10s of the comprehensive air-quality model with extensions (CAMx) photochemical grid model has been developed, which includes two options for representing particulate matter (PM) size distribution: (1) a two-section representation that consists of fine (PM2.5) and coarse (PM2.5-10) modes that has no interactions between the sections and assumes all of the secondary PM is fine; and (2) a multisectional representation that divides the PM size distribution into N sections (e.g., N = 10) and simulates the mass transfer between sections because of coagulation, accumulation, evaporation, and other processes. The model was applied to Southern California using the two-section and multisection representation of PM size distribution, and we found that allowing secondary PM to grow into the coarse mode had a substantial effect on PM concentration estimates. CAMx was then applied to the Western United States for the 1996 annual period with a 36-km grid resolution using both the two-section and multisection PM representation. The Community Multiscale Air Quality (CMAQ) and Regional Modeling for Aerosol and Deposition (REMSAD) models were also applied to the 1996 annual period. Similar model performance was exhibited by the four models across the Interagency Monitoring of Protected Visual Environments (IMPROVE) and Clean Air Status and Trends Network monitoring networks. All four of the models exhibited fairly low annual bias for secondary PM sulfate and nitrate but with a winter overestimation and summer underestimation bias. The CAMx multisectional model estimated that coarse mode secondary sulfate and nitrate typically contribute <10% of the total sulfate and nitrate when averaged across the more rural IMPROVE monitoring network.
已开发出带有扩展的综合空气质量模型（CAMx）光化学网格模型的4.10s版本，其中包括两种表示颗粒物（PM）粒径分布的方法：（1）两段式表示，由细颗粒物（PM2.5）和粗颗粒物（PM2.5 - 10）模式组成，两段之间无相互作用，且假定所有二次颗粒物均为细颗粒物；（2）多段式表示，将PM粒径分布划分为N个段（例如，N = 10），并模拟由于凝并、积聚、蒸发及其他过程导致的段间质量转移。该模型采用PM粒径分布的两段式和多段式表示应用于南加州，我们发现允许二次颗粒物增长到粗颗粒物模式对PM浓度估算有重大影响。然后，CAMx以36公里的网格分辨率采用两段式和多段式PM表示应用于美国西部1996年全年。社区多尺度空气质量（CMAQ）模型和区域气溶胶与沉积建模（REMSAD）模型也应用于1996年全年。在跨部门受保护视觉环境监测（IMPROVE）和清洁空气状况与趋势网络监测网络中，这四个模型展现出相似的模型性能。所有四个模型对二次硫酸盐和硝酸盐的年偏差都相当低，但存在冬季高估和夏季低估偏差。CAMx多段式模型估计，在更偏远的IMPROVE监测网络中进行平均时，粗颗粒物模式的二次硫酸盐和硝酸盐通常占总硫酸盐和硝酸盐的比例小于10%。
