Conceptual Design of a Massive Aerometric Tracer Experiment (MATEX)

Abstract

in conjunction with The MATEX Design Group A hypothetical field experiment is evaluated that relates, through tracer releases, reactive pollutant emissions to long range transport and deposition. The feasibility of such an approach is established provided certain requirements can be met. The experiment must: (a) trace emissions from several sources simultaneously and repetitively over an extended period of time, (b) link a tracer to the chemical behavior of emissions, and (c) apply a statistically sound method of guidance for deducing empirical source-receptor relationships (SRRs) while accounting for natural variability. One design approach would use perfluorocarbon tracers (PFTs), which are nonreactive in the atmosphere, to simulate the transport and dispersion of reactive species such as sulfur and nitrogen oxides. Conversion and loss factors would be calibrated using isotopic sulfur and nitrogen compounds with PFTs, in combination with aerometric and deposition observations. An experimental concept is described that determines SRRs for deposition from observations and their interpolation, synthesized by an empirical model. If implemented, the experiment would be very expensive and has high design risk for achieving its goals given present knowledge.Among the points of scientific debate on regional scale air pollution phenomena is the issue concerning source-receptor exposure relationships (SRRs). Research has implicated air pollution at great distances from its origin as an important factor, for example, in acid deposition. These results have stimulated a call for increased emission control over broad industrialized areas of the Northern Hemisphere to reduce deposition levels. Estimated costs for widespread decreases in emissions have been so large that attention has centered on selective emission reductions. Selection of sources would be made to protect certain environmentally susceptible areas. However, implementation of such a strategy requires a specific knowledge of pertinent source-receptor relations.One approach to development of a strategy for selective emission control uses numerical simulation (air quality models). The models are numerical representations of atmospheric processes which intervene between source emission and the deposition of material. These models are required to estimate results of phenomena over subcontinental areas, and as a consequence must be highly simplified. Additionally, many of the processes to be simulated are not fully understood. For verification, the output from models may be compared with available observations, which themselves are incomplete with respect to spatial and temporal coverage and are subject as well to measurement error. For both reasons, the output of physical simulation models cannot yet be considered to provide a reliable description of the SRRs in acid deposition. Discussion of regionwide pollution control opCopyright 1987-APCA tions and opportunities thus has been inhibited by the lack of confidence in modeling results.In view of the limitations of p...

Visibility: Science and Regulation

“…I also disagree with Dr. Mathai regarding the peerreviewed MATEX study design, 66 which should be required reading for those who believe that releasing an inert tracer gas from a source is the "magic bullet" for estimating SO 4 2-contributions to haze. MATEX clearly and definitively quantified the deficiencies of this approach, and these findings were reinforced by subsequent tracer-release source attribution studies.…”

“…The discussion of MATEX, 66 a proposal that was never implemented, also would have been more appropriate under the science section. Discussion of the "Clean Power Act of 2001" (S556), a bill currently under consideration by the U.S. Senate, also was inappropriate.…”

Air quality measurements—From rubber bands to tapping the rainbow

“…A standard answer is "The more the better," but this is not always practical or acceptable to sponsors. The Massive Atmospheric Transport Experiment (MATEX) design (Hidy et al, 1985a(Hidy et al, , 1985b(Hidy et al, , 1987 went to great lengths to evaluate methods and costs for establishing the influence of long-range transport of power-plant sulfur emissions in the eastern United States using reactive sulfur isotopes combined with nonreactive chlorohydrocarbon tracer gases. This analysis established that the simple concept of coreleased reactive and nonreactive gases was impractical owing to the high costs for sulfur isotopic plume tracing and ambient sampling.…”

“…This analysis established that the simple concept of coreleased reactive and nonreactive gases was impractical owing to the high costs for sulfur isotopic plume tracing and ambient sampling. MATEX evolved into a simpler design, the EMEFS (Hidy, 1987;AES, 1993;Ruff et al, 1985), which favored spatial monitors placed specifically for improved model evaluation. The EMEFS design did not analyze the need for sites to characterize both regional-scales >100 km and neighborhood to urban scales <100 km.…”

Characteristics of Winter and Summer Aerosol Mass and Light Extinction on the Colorado Plateau

“…The fine aerosol species are classified into five major types: sulfates, nitrates, organics, lightabsorbing carbon, and soil. [3][4][5][6][7] Other fine species such as nonsoil potassium, sea spray, and other trace elements are also estimated but are less important from a visibility standpoint. Estimation of the major aerosol species is discussed below.…”