NO{sub x} sensitivity of Phoenix, AZ ozone
- Arizona Dept. of Environmental Quality, Phoenix, AZ (United States)
Of critical concern in the Urban Airshed Model (UAM) simulations of Phoenix, AZ ozone was the issue of NO{sub x} sensitivity. With the base case inventory of the Voluntary Early Ozone Plan, which had a mass VOC/NO{sub x} ratio in the inventory of 1.06, the airshed had a decided NO{sub x} disbenefit. To determine whether this NO{sub x} disbenefit would prevail with different emissions inventories, alternative inventories were constructed within the limits of the estimated uncertainties for each combination of major source category and pollutant combination. These alternative inventories had mass VOC/NO{sub x} ratios both lower and higher than the base case inventory. Paired UAM simulations of each inventory with 10% NO{sub x} reductions were performed for each alternative. In varying the mass VOC/NO{sub x} inventory ratio from 0.6 to 2.1, the NO{sub x} disbenefit prevailed with ratios of up to 1.7, while at higher ratios, the NO{sub x} benefit prevailed. For the Reanalysis of the Voluntary Early Ozone Plan, a revised base-case inventory was constructed. This inventory differed substantially from its predecessor in VOC and NO{sub x} tonnages in the onroad and offroad mobile source categories and for biogenic emissions, but the overall VOC/NO{sub x} tonnages were similar to the earlier inventory. This inventory also showed a NO{sub x} disbenefit. Two series of extensive emission sensitivity tests showed that the NO{sub x} disbenefit prevailed with all inventories that could be considered plausible.
- OSTI ID:
- 682185
- Report Number(s):
- CONF-980632--
- Country of Publication:
- United States
- Language:
- English
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