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CNAPTERFOUR Environmental i~onseguences • There was no removal of NOz during transport to the Class I area. • The annual deposition rate of nitrogen was then calculated, assuming a deposition velocity of 0.007 m/sec. • A ratio of total to dry deposition of 2. • The Ned Wilson Lake ANC of 37.0 µeq/1 was used. The screening analysis indicates a potential pH change not exceeding 0.0012 an~i a potential change of ANC of 0.39 percent. Additional information relative to results for acrid deposition and ANC/pH calculations for Ned Wilson Lake are presented in Table D-5 in Appendix D. The computed pH and ANC changes aze significantly below the significance thresholds of 0.1 pH unit change and 10 percent reduction in ANC. The nitrogen deposition rate is significantly below the U.S. Forest Service (USFS) significance threshold of 3 kg/ha-yr for terrestrial ecosystem effects. Therefore, it is concluded that the Proposed Action would not significantly affect terrestrial systems or lake water chemistry at the Class I azea. 4.5.2.2 Accelerated DevelopmentAltemative The emissions associated with the Accelerated Development Alternative would result in greater estimated annual emissions. The production of soda ash would approximately triple (1.4 million tons per year to 4 million tons per yeaz soda ash) relative to the Proposed Action. The increased levels of construction and operation activities and the increased number of boilers, dryers, and related vehiculaz traffic would increase emissions. Estimated emission levels for the Accelerated Development Alternative would range from double to triple the Proposed Action. Worst case ambient air quality impacts were estimated for the Accelerated Development Alternative by tripling the maximum concentrations presented in Tables 4.5-3 artd 4.5-4 for both the Piceance and Pazachute Sites, respectively. Estimates for the Accelerated Development Alternative at the Piceance Site and Pazachute Site aze presented in Table 4.5-8 and 4.5-9. The conservative estimate for the Accelerated Development Alternative based o~i dispersion modeling performed for this project (Proposed Action) indicated that the maximum ground level concentrations (total concentration) predicted for all pollutants (PMIO, NOz and CO) are below the applicable standazds (NAAQS(CAAQS concentrations) (Tables 4.5-8 and 4.:i-9}. 4-30 Meteorology and Air Quality