Emissions meteorological factors

The effective height of an emission rarely corresponds to tlie physical height of tlie source or the stack. If tlie plume is caught in tlie turbulent wake of tlie stack or of buildings in the vicinity of tlie source or stack, tlie effluent will be mixed rapidl) downward toward the ground. If the plume is emitted free of these turbulent zones, a number of emission factors and meteorological factors influence tlie rise of the plume. 

FIGURE 2.3 The ability to detect trends in atmospheric emissions can be strongly affected by the distance from the source (top) and meteorological factors such as wind direction (bottom). These measurements were made near a Hg source in southeastern Idaho. (Source Abbott 2003, unpublished data, with permission.)... 

Clearly, the concentrations of pollutants in ambient air, and hence their impacts, are determined not only by their rates of emissions but also by the nature and efficiencies of their chemical and physical sinks, e.g., chemical transformations, as well as wet and dry deposition to the earth s surface. To a large extent, these competing processes are affected not only by direct dispersion and transport but also by such meteorological factors as temperature, sunlight intensity, and the presence of temperature inversions as well as clouds and fogs. 

Miller, J. M. Tellus. in press) have examined the transport of North American sulfur emissions across the north Atlantic Ocean to Europe. In a review of available precipitation-sulfate data from the north Atlantic and adjacent coastal regions, they report a concentration field consistent with known source distributions and meteorological factors. The excess sulfate concentration of marine background... 

A number of meteorological factors affect the results of soil gas sampling for Hg. Table 12-III shows the effect of heavy rain on the Hg content of soil gas. In addition, barometric pressure and air temperature affect Hg emission from soil (McCarthy et al., 1969 Kromer et al., 1981 McNemey and Buseck, 1973) (Fig. 12-32). 

Dijfuse sources are highly dynamic, spread out pollution sources and their magnitude is closely related to meteorological factors such as precipitation. Major diffuse sources under this definition include surface runoff (load from atmospheric deposition), groundwater, erosion (load from eroded material), diffuse loads of paved urban areas (atmospheric deposition, traffic, corrosion) including combined sewer overflows, since these events occur discontinuously over time and are closely related to precipitation (it has to be pointed out that emissions from urban areas are also partly involved in the point source term, so these discharges are not constant in reahty). Both point and diffuse sources contribute to the total contaminant load of rivers. 

The seasonal variations of trace metal composition of atmospheric aerosols are controlled by several meteorological factors such as temperature, humidity and wind velocity and direction. Cold seasons are usually characterized by persistent thermal inversions, high precipitation and low wind velocities which favor the accumulation of anthropogenic exhaust emissions and reduce the presence of road... 

Chapman RS, Watkinson WP, Dreher KL, Costa DL (1997) Ambient particulate matter and respiratory and cardiovascular illness in adults particle-borne transition metals and the heart-lung axis. Environ Toxicol Pharmacol 4 331-338 Charron A, Harrison RM (2003) Primary particle formation from vehicle emissions during exhaust dilution in the roadside atmosphere. Atmos Environ 37 4109-4119 Cuhadaroglu B, Demirci E (1997) Influence of some meteorological factors on air pollution in Trabzon city. Energy Build 25 179-184 Department of Statistics, Singapore, http //www.singstat.gov.sg... 

The complexity of the chemistry, and meteorological factors, make it difficult to study the relationship between VOC, represented by C2H4 in the example above, and emission (where represents NO or NO2) to the concentration of O3. Nevertheless, some general trends will be outlined below. 

Air pollutant concentrations vary in time and space under the influence of many factors, which are summarized in Table 1. Discussion of these factors may be found in basic texts on air pollution (i). Potential determinants of ambient exposure (such as meteorological factors, traffic volume, and industrial emissions) and suspected health effects also show spatial and temporal variation. 

The role of meteorological and climatic factors and their variability. Ambient air quality (e.g., oxidant concentrations) and deposition that can affect the emissions to indicator relationship. Sampling frequency is also an important attribute of a monitoring program that strongly influences the ability to detect trends. 

Ammonia volatilization from fertilizers is a function of the type of fertilizer, soil conditions, meteorological conditions-temperature, wind speed, precipita-tion-and fertilizer management. Table 8.6 shows the global use of nitrogenous fertilizers and the corresponding NH3 emissions based on empirical emission factors for different fertilizer types in temperate and tropical conditions (Bouwman... 

The determination of which features the underlying factors are composed of provides a basis for attaching a physical Interpretation to the factors. Varlmax rotation of the PGA may be utilized to aid In the Interpretation of the factors. Hierarchical dendrograms Indicate feature clusters whose composition are analogous to PC factors. The physical Interpretation of the clusters and principal components Indicates the Influence of pollution emission sources or meteorological processes on the rainwater composition at an Individual monitoring site. 

The results of the PCA from each subset are similar except that the data subsets which did not either Include the meteorological data or normalize the data to reduce meteorological variability (subsets 2 and 3) were not able to separate several of the components probably due to the atmospheric masltlng effect. Information on the wind direction and rainfall quantity dependence of seasalt and metals Is obtained when meteorological data are Included In the analysis. From the standpoint of separation of chemical factors the fourth subset (normalization to fractional composition) provided the best resolution of the data. Using deposition or concentrations, a component that Indicated a combined Influence of sulfate, nitrate, lead and calcium emission sources was resolved Into separate components when the fractional composition data were analyzed by PCA. 

Cluster analysis Is used to determine the particle types that occur in an aerosol. These types are used to classify the particles in samples collected from various locations and sampling periods. The results of the sample classifications, together with meteorological data and bulk analytical data from methods such as instrunental neutron activation analysis (INAA). are used to study emission patterns and to screen samples for further study. The classification results are used in factor analysis to characterize spatial and temporal structure and to aid in source attribution. The classification results are also used in mass balance comparisons between ASEM and bulk chemical analyses. Such comparisons allow the combined use of the detailed characterizations of the individual-particle analyses and the trace-element capability of bulk analytical methods. 

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