Source apportionment of ammonia at Rocky Mountain National Park using modeled conservative tracer releases

摘要: All gaseous species show pronounced diurnal variability throughout the year. Typically minimum concentrations occur during evening hours and maximum in the late afternoon. NH 3 has the highest or greatest difference ratio, defined as (maximum median-minimum median)/(maximum median) of about 0.65, while NO x and NO y are also very high at about 0.50. The difference ratio for PM1. 0 is lower but still high at 0.40. For the most part, the use of NH x in the receptor model yielded higher correlations and variance explained than did URG data, suggesting either sources of reduced nitrogen other than ammonia or possibly the chemiluminescence measurement has a higher precision than the URG measurement. The relative apportionment between sources is approximately the same whether URG or chemiluminescence measurements are used. Two objectives of the study were to develop an approximate understanding of the relative contribution of ammonia sources in and outside the state of Colorado to measured reduced gaseous ammonia species in RMNP and to assess whether large ammonia emissions in the agricultural area of the Midwestern portion of the United States contributed significantly to ammonia in RMNP. In answer to the first question, the analysis suggests that slightly more ammonia measured at RMNP originates from instate sources. However, within in the uncertainty of the apportionment methodology, it is fair to say that it is about a 50: 50 split between in-state versus out-of-state sources. In answer to the second question, it seems pretty clear that very little of measured ammonia at the receptor site had its origins in the …