To solve traffic congestion in Bangkok, the Bangkok Mass Transit system (BTS) constructed an overhead rail system with 24 stations. The BTS train station, S2, in this study area covers Silom road and obstructs the air pollutant dispersion in a congestion area. The 1: 200 physical model of the buildings along Silom road with the train station, S2, was simulated in this research to determine the air pollutant dispersion in the train station area. A tracer gas (CO₂) was emitted from a simulated line source with emission rates of 0.383, 0.681, 1.293, 2.586, 5.177 and 10.77 mg/min to simulate actual pollutant emission rates. The CO₂ gas was sampled at 55 locations in the model. The Kriging method was used to interpolate the data in the study area. . Emission rates were used to make the difference between measured CO₂ in the model area and ambient CO₂ large enough to be differentiated. Regression Analysis was used to relate analytically the mass emission rate to the CO₂ concentration. The results indicate that the maximum CO concentrations exceed the 30 ppm Bangkok standard along the Southeast side of Silom Road at the passenger platform level. Drivers will acquire more harmful levels of CO than pedestrians at street level, especially near the Southwest end of the train station. NO₂ concentrations do not exceed the standard (0.17 ppm) at street level. The highest predicted VOC is 1.05 ppm. These results may be used in the future for numerical modeling study. / Master of Science

Air quality in the Shenandoah Valley has deteriorated in recent years. The valley exceeds the National Ambient Air Quality Standards for ozone (O3) a few days each year, and with stricter fine particulate matter (PM2.5) standards coming into effect, the valley risks exceeding those as well. Visibility is poor in the valley region, and the haze obscures the spectacular vistas from the Shenandoah National Park. To solve the growing problem local governments in the valley joined forces to find economically and politically feasible ways to reduce air pollution. In this study we aim to provide the scientific basis for air quality management strategies through modeling the sensitivity of various pollutants to changes in emissions. We distinguish between locally generated versus regionally transported air pollution as well as assess the impacts of proposed local air pollution control measures on ambient air quality in the valley. The first part of this thesis assesses air pollutant emissions in the Shenandoah Valley. Emissions were assigned to one of 14 source categories and allocated by county or city. Biogenic sources were responsible for 56% of the volatile organic compounds (VOCs) emitted in the valley. VOCs are important because they, together with nitrogen oxides (NOx) react to form O3 in the presence of sunlight. On-road and off-road mobile sources were the largest anthropogenic sources of VOCs as well as 63% of the NOx. PM2.5 emissions were not dominated by any single source, but fuel combustion, dust, and agriculture were important contributors. The second part of this thesis focuses on modeling ambient air pollution concentrations in the Shenandoah Valley based on the emissions generated in the first portion. We developed a set of three alternative emissions scenarios for comparison to the base case. We first zeroed anthropogenic emissions in the valley, allowing us to determine how much pollution was produced by local sources versus transported into the valley from upwind areas. We then developed a scenario that contained nine different pollution reduction strategies being considered by local governments. Finally we modeled a similar scenario in which we predicted the impact of ten proposed greenhouse gas reduction strategies on concentrations of O3 and PM2.5. We found that PM2.5 concentrations fell when emissions in the valley were reduced, but O3 did not. PM2.5 concentrations fell by 26-57% for the Zero Case and by 10-27% for the other two cases, depending on the time of year and location. Conversely for O3 there was either no change in most seasons or a small increase in concentrations in the fall. These results suggest that PM2.5 in the valley can be controlled with local measures but O3 is a more geographically wide problem. / Master of Science

Three air pollution models are presented which address themselves to the specific problems of 1) pinpointing locations of relative maxima, 2) producing air quality maps efficiently, and 3) presenting. graphic representation of patterns of pollution over a mesoscale region. MAXPOL-A is a semiempirical, source-oriented, microscal0, deterministic, climatological air pollution model which uses a simplex search algorithm to walk, one step at a time, towara the area of maximum concentration. Input parameters govern the length of walk and the precision with which the maximum is located. SIMPLOT is a semiempirical, source-oriented, stochastic, climatological air pollution model and employs the concept of stochastic simulation as well as simulation ! in the usual sense to obtain estimates of air quality. SIMPLOT also uses a technique. called the plume projection procedure which allows it to generate all of the receptors for each eliminating source and meteorological extensive checking. DAMPS condition thus is a dynamic, segmented, source-oriented, deterministic, mesoscale model which keeps track of all air parcels over a 60 by 60 kilometer region. DAMPS updates all receptors hourly and produces three types of graphic output. DAMPS also utilizes the plume projection procedure used in SIMPLOT. Computer programs foe each model are included as are several examples of the use of each model. / Ph. D.

At international border areas that suffer from poor quality, assessment of pollutant sources and transport across the border is important for designing effective air quality management strategies. As part of the Cal-Mex 2010 field campaign at the US-Mexico border in San Diego and Tijuana, we measured black carbon (BC) concentrations at three locations in Mexico and one in the United States. The measurements were intended to support the following objectives: to characterize the spatial and temporal variability in BC concentrations and emissions in the border region, to identify potential source areas of BC emissions, and to characterize the cross-border transport of BC and assess its impact on local and regional air quality. BC concentrations at Parque Morelos, the campaign's supersite, averaged 2.1 ?g m?? and reached a maximum value of 55.9 ?g m??. This average value is comparable to levels in large American cities like Los Angeles and similarly sized Mexican cities like Mexicali. The maximum value occurred near midnight, and similar incidents were observed on nearly half of the overnight monitoring periods. BC and carbon monoxide (CO) were strongly correlated at the Mexican sites. The BC/CO ratio was ~3 times higher in Tijuana than in Mexico City, suggesting that gasoline-powered vehicles in Tijuana emit more BC than is typical or that diesel vehicles comprise a relatively high proportion of the vehicle fleet. Tijuana's emissions of BC are estimated to be 380-1470 metric tons yr??. BC measurements were used in conjunction with modeled wind fields to simulate forward and backward particle trajectories. Generally, BC in Tijuana appears to originate locally, as backward simulations showed transport from the US into Mexico at only one site. The majority of the trajectory analyses indicate that there is often transport from Tijuana into the US, crossing the border in a northeasterly direction to the east of San Diego-Tijuana and sometimes as far east as Imperial County at the eastern edge of California. These results suggest that any air quality management strategies considering BC should account for contributions from the border region, as BC is chemically inert in the atmosphere and can travel up to thousands of kilometers. / Master of Science

The increased use of residential wood and coal stoves in recent years h.as caused a growing concern for polycyclic aromatic hydrocarbon (PAH) emissions from these stoves. Design of stoves that reduce PAH emissions has been hampered because existing PAH measurement techniques are slow, complex, and expensive. This study investigates two simple, inexpensive, real-time PAH measurement techniques which might be suitable for testing stoves. The first uses a device, called the "moving tape sampler" (MTS), that collects particulate samples on filter paper tape and uses sensitized flourescence to measure total PAH on the tape. The MTS results are compared to the results of a conventional PAH measurement technique, but no definite relationship between the two is found. Uncertainties about the conventional technique make it unclear whether one or both of the techniques give incorrect emission rates. The second method is the use of CO and NO_x as proxy compounds to infer PAH emissions. A plot of CO emission factors against PAH emission factors suggest CO as a proxy for PAH emissions while a similar plot for NO_x gives some evidence of NO_x being an "inverse" proxy for PAH emissions. The lack of a trusted PAH measurement technique has hampered the evaluation of both the MTS and proxy techniques. / Master of Science

Lichens have been used extensively and with considerable success as bioindicators of atmospheric pollution in North America and Europe for more than thirty years. Little research has followed in tropical and subtropical regions where population growth is rapid and environmental pressures unprecedented. However, taxa used as bioindicators in other studies and/or taxa having this potential, occur naturally in Central Florida. A new potential major source of pollution, the coal-fired Curtis H. Stanton Energy Center, is about to begin operation providing the opportunity to determine the extent of impact. Therefore, lichen monitoring sites have been established and the collection of baseline data reflecting species diversity, frequency, overall cover and vitality has been accomplished. These locations will be preserved for future monitoring activities. Voucher specimens and photographic documentation of sample populations have been deposited in the herbarium of the University of Central Florida.

Testing was conducted on the pre-prototype unit of an innovative indoor air pollution abatement system which used catalytic ozonation as a mechanism for oxidation and removal of organic contaminants. The system was evaluated for carbonyl production when the system was challenged with chemicals used to simulate polluted indoor air. Carbonyl compounds, which are potentially toxic partial oxidation products, were monitored using EPA Method I P-SA. The objectives of the study were to qualitatively and quantitatively determine if carbonyls were formed in the airstream when the system was operated, and if so, to determine what factors affected the concentrations of these compounds. Trials were conducted using benzene and 2-butanol as challenge chemicals. A variety of test conditions were used to determine factors affecting carbonyl concentrations, including temperature, presence of challenge chemicals, sample location, relative humidity, presence of ozone in the airstream, and two interaction variables. No carbonyls were detected in the airstream within the air cleaning system when benzene was used as the challenge chemical. When 2-butanol was used, four carbonyls were detected at various stages of the system, under varying conditions. The carbonyls detected during these trials were formaldehyde, acetaldehyde, acetone, and butanone. Statistical analyses of the data indicated that the pre-prototype unit of the air cleaning system caused increased levels of acetaldehyde and butanone, and possibly formaldehyde, in the airstream when challenged with 2-butanol. Acetone concentrations in the system were affected only by humidity conditions. / Master of Science

An existing individual tree growth and yield model (PT AEDA2) was modified study the potential effects of air pollution stress on the growth and yield of loblolly pine plantations. These modifications were based on the assumption that pollution stress on older trees could result in reductions in diameter and height growth, decreases in photosynthesis, and increased losses of older foliage, as demonstrated in some seedling studies. One modification applied differential levels of reductions of diameter and height increments to various percentages of trees. Results indicated no sizeable losses on total volume per acre except at severe stress levels (-32 and -64 percent annual diameter and height increments on 50 and 67 percent of the trees). Another modification consisted of developing a measure of photosynthetic potential to drive diameter and height growth in the model. This new measure was an estimate of foliage weight which was weighted by a factor of photosynthetic efficiency and needle retention for each age class of needles. Reductions of these weighting factors were applied to simulate air pollution stress. Results of this modification show that if air pollution does cause a decrease in photosynthesis and needle retention rates, the impact on over-all stand productivity is minimal. These results are not intended to be quantitative estimates of the effect of air pollution on tree growth but to identify potential areas within an existing growth and yield model where biologically-oriented processes to simulate air pollution impact can be incorporated. / Master of Science

A Dispersion model for ozone inside the rectangular duct of an indoor air quality pilot plant was simulated. Using this the concentration profiles of ozone at several points downstream of ozone insertion were simulated and they matched well with experimental results. Recommendations for future work are cited. A thermodynamic study was conducted to check the levels of concentration in which certain toxic compounds could be present due to the oxidation of pre-determined chlorinated compounds. STANJAN, a package which solves for equilibrium concentrations using the element potential method, was used. Recommendations for future work are cited. A Reaction model was developed for the global oxidation reactions occurring in the catalyst bed which is situated downstream of the ozone insertion. Once this was done, the effect of moisture and temperature were studied qualitatively and recommendations for further work are Cited. / Master of Science

Field surveys and biomonitoring network experiments were conducted in selected areas in South Africa to assess possible air pollution damage to vegetation. During field surveys, atmospheric fluoride was identified as an important pollutant that damaged vegetation in residential areas north of Cape Town. Gaseous air pollutants, including acid deposition and acidic mist, probably play a major role in the development of characteristic air pollution injury symptoms observed on pine trees in the Eastern Transvaal area. The impact of urban air pollution in the Cape Town area was evaluated by exposing bio-indicator plants in a network of eight biomonitoring network stations from June 1985 to May 1988. Sensitive Freesia and Gladiolus cultivars were used to biomonitor atmospheric fluoride, while a green bean cultivar was used as a biomonitor of atmospheric sulphur dioxide and ozone. At one location, bio-indicator plants were simultaneously exposed in a biomonitoring network station (plant cages), open-top chambers (filtered and unfiltered), as well as in open plots. The responses of plants grown under these different conditions were compared. During both the winter and summer seasons, ambient fluoride concentrations were estimated to be particularly high at the Loumar biomonitoring station (eastern side of Cape Town), as compared to that at the other biomonitoring stations. Elevated levels of atmospheric fluoride, as well as sulphur dioxide, appeared to prevail in the vicinity of industries located in the northern suburbs of Cape Town (Bothasig, Table View and Edgemead). Interveinal bleaching, which is characteristic of sulphur dioxide injury, was regularly observed on bean plants exposed at the Bothasig biomonitoring station and was usually determined to be significantly worse at this location than at the other biomonitoring stations. These results were confirmed by the evaluation of foliar sulphur content Ambient pollutant concentrations appeared to be effectively reduced inside filtered open-top chambers, as exemplified by higher biomass production and lower foliar fluoride and sulphur levels in the relevant bio-indicator species, compared to that of plants grown in the open plots. The methodology used during this research provided baseline data of the impact of air pollution on vegetation in South Africa which, in the absence of networks of sophisticated state of the art equipment, can be applied to aid in air pollution control strategies. / Ph. D.