Meteorological and Back Trajectory Modeling for the Rocky Mountain Atmospheric Nitrogen and Sulfur Study II

Table 4

Mean measured 24-hour ammonia concentrations by season in the far right column and percent attributions ± standard deviations by TrMB analysis for the 2006 RoMANS I (italic font) and 2009 RoMANS II studies. The values in the bottom row (bold font) are concentration weighted means of the four 2008/09 seasons.The RoMANS II results are composite results from 360 TrMB trials for each season using concentrations for the correct time, but allowing all other parameters shown in Table 3 to vary. See Table 5 and Figure 11 for locations.

Season	NE Colorado (%)	SE Colorado (%)	CO Front Range (%)	Western Colorado (%)	Total Colorado (%)	Eastern U S; (%)	Western U S; (%)	URG 24-hr Conc (μg/m^3)
RoMANS I; spring 2006	7 ± 1	NA	9 ± 3	39 ± 4	56 ± 5	8 ± 2	35 ± 4	0.14
RoMANS I; summer 2006	9 ± 5	NA	15 ± 4	24 ± 5	50 ± 7	21 ± 3	29 ± 5	0.35
RoMANS II; winter 2008/09	11±9	0±2	7±6	34±14	52±12	5±6	44±12	0.09
RoMANS II; spring 2009	10±7	3±4	4±3	27±10	43±12	12±10	45±12	0.32
RoMANS II; summer 2009	20±6	0±1	2±3	30±12	53±12	8±7	39±9	0.31
RoMANS II; fall 2008/09	17±11	4±7	8±5	18±9	47±12	6±7	47±13	0.23
RoMANS II; overall 2008/09	15 ± 8	2 ± 4	5 ± 4	26 ± 11	48 ± 12	9 ± 8	43 ± 11	0.24