Syftet med denna studie var att undersöka vilka effekter luftföroreringar har på lavar och grönalger som växer på lindar, genom att jämföra lavfloran i urban miljö och i landsbygdsmiljö. Mer specifikt var syftet att utreda hur avstånd till närmaste väg, trafikintensitet och trädets exponerade respektive icke-exponerade sida gentemot en väg påverkar lavfloran i urban miljö. 18 utvalda lavarter samt grönalger eftersöktes på 86 lindar i urban miljö och 37 i landsbygdsmiljö inom Norrköpings kommun. Resultaten visade att artantalet, samt förekomsten och täckningsgraden för flertalet lavar var större i landsbygdsmiljö jämfört med urban miljö. Kortare avstånd till närmaste väg och hög trafikintensitet hade negativ effekt på flertalet lavar. I båda fallen visades det motsatta för grönalger. Det fanns ingen skillnad i förekomster av lavar om de exponerades utåt mot vägen eller bort från vägen. / The aim of this study was to investigate which effects air pollution has on epiphytic lichens and green algae in urban and rural environment, respectively.  More specifically, the aim was to investigate the effects on the lichen flora of distance to the nearest road, traffic volume and to compare the effect of tree sides exposed and not exposed to roads in the urban environment. 18 selected lichen selected species and green algae as a taxonomic group where searched on 86 lime trees in urban and 37 in rural environments in the Norrköping municipality. The species number was higher and the majority of the lichens occurred more often and showed a higher cover on trees in rural areas compared to trees in the urban environment. Shorter distance to the nearest road and high traffic volume had a negative impact on the majority of lichens. In both cases the opposite was shown for the green algal group. The lichens occurred equally often on the sides of the trees that were exposed to the road as on the sides that were not exposed to the road.

This thesis characterizes the mass and chemical composition of the fine particle air pollution over several cities in South Asia and quantifies how major sources impact the observed levels by using Chemical Mass Balance modeling with organic compounds as tracers. During February 1999, as part of the INDOEX program, a study was conducted to measure the size distribution and chemical composition of the fine particles in a remote island in Maldives off the coast of India. We found that the fine particle concentrations were comparable to those found in major cities in the United States, and were surprisingly high for a background site. 10-day backwind trajectories pointed the source region towards the Indian subcontinent; other INDOEX studies confirmed the presence of a thick haze layer over the Indian Ocean and the subcontinent during the time of the experiment. Motivated by these findings, a detailed analysis of ambient PM2.5 was carried out in Delhi, Mumbai, Kolkata, and Chandigarhfour cities located upwind of the island in Maldives. Seasonality of the fine particle concentrations was observed in each of these cities with the highest concentrations occurring during the wintertime and the lowest concentrations during the summer. Size distribution and chemical composition of the fine particle emissions from five Bangladeshi biomass (rice straw, coconut leaves, dried cow dung, synthetic biomass log, and jackfruit wood) and three Asian coals (Bangladeshi, Indian, and Chinese) were characterized and important source signatures were identified. Finally, recently developed chemical tracer techniques were applied to the ambient samples from North India to differentiate between the contributions from the many different source types. The emission profiles and source signatures from the source tests conducted previously along with the ones conducted using the Indian Subcontinent fuels were used as inputs to the model. These results serve several purposes. First, they provide a description of the mass and detailed inorganic and organic chemical characteristics of fine particulate matter conducted for the first time ever in this region. Second, the source apportionment study will help to define the relative importance of those sources that should be included within an air quality control program. Chemical tracer techniques are particularly attractive for application in regions that have not been studied previously because they are able to yield rapid insights into the causes of a local air pollution problem before the completion of an accurate emissions inventory. Third, the source tests results will prove useful in constructing and evaluating regional emission inventory and assessing source impacts on air quality. Fourth, this work has been carried out with collaborations from Georgia Tech and several other Indian research institutions where pollution control personnel in India was trained in the operation of air sampling equipments that were left for continued monitoring, thus contributing to technology transfer and knowledge transfer from the US.

Master's thesis. / Format: PDF. Bibl.

China faces a very serious environmental situation as a result of severe environmental pollution in the country. Smog in eastern and northern China is a wake-up call for actions to be taken to improve the ecological environment. As a student in landscape architecture, my practicum topic focuses on a design that can reduce the problem of air pollution in China. A bicycle infrastructure design in Nanjing is proposed to encourage people to ride instead of drive. By creating a safe, functional, efficient, recreational and attractive bicycle system, more people will love cycling and realize the importance of “green travel”. At the same time, I would like to try to improve Chinese people’s awareness of environmental protection through a well-designed bicycle infrastructure. / February 2016

Heterogeneous reactions have the potential to significantly impact urban ozone formation and total reactivity of the atmosphere. This dissertation used comparisons between photochemical modeling predictions and field measurements to examine heterogeneous N₂O₅ chemistry in Southeast Texas. Heterogeneous reactions of N₂O₅ can lead to two different products: nitric acid (HNO₃) and nitryl chloride (ClNO₂). The formation of HNO₃ results in a loss of reactive nitrogen from the atmosphere. In contrast ClNO₂ photolysis forms Cl radicals and NO₂, both of which promote ozone formation in the troposphere. Preliminary modeling identified key uncertainties and the need to perform more refined modeling which included updated PM emissions estimates, an updated gas-phase N₂O₅ hydrolysis reaction rate constant, updated reactive uptake coefficients, and the inclusion of ClNO₂ as a product of heterogeneous N₂O₅ uptake. Refined modeling which incorporated all of these improvements was carried out and was the first comprehensive modeling of this chemistry performed for an urban air pollution episode. Comparisons of aerosol surface area concentrations, N₂O₅ concentrations, HNO₃ concentrations, and ClNO₂ concentrations with ambient data showed that model predictions were reasonable. The exceptions to this were 1) over-predictions of aerosol surface area concentration peaks at altitudes above 1500 meters and 2) over-prediction of N₂O₅ concentrations in the Houston Ship Channel. Further analysis is needed to identify the reasons for these over-predictions. Other key findings from this modeling include the model prediction of inland chlorine concentrations high enough to form ClNO₂ and the prediction that a large portion of atmospheric chlorine is cycled through ClNO₂, therefore making the inclusion of ClNO₂ into photochemical models essential for properly simulating chlorine chemistry. In addition, modeling suggested that the chemistry leads to significant increases of NO[subscript x] at night, but decreases in daytime NO[subscript x] concentrations and that the overall effect was to decrease ozone concentrations. Further investigation into the effect of ClNO₂ as a chlorine source showed that likely ozone increases in the Houston area caused by the presence of this compound are on the order of several ppb. Further analyses showed that vertical dispersion and local atmospheric composition moderated the effect of nitryl chloride on ozone mixing ratios. / text

published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

Background There have been many multicity studies assessing health effects of the population’s exposure to PM10. They assume that there is homogeneous exposure to PM10 and the monitoring locations are representative of the population’s exposure. In a densely urban environment, like Hong Kong, street canyons are common and could alter PM10 exposure. The horizontal and vertical dispersion of PM10 in the urban environment is complex due to the interactions of street geometric, metrological and pollution source conditions. The airGIS/OSPM is a box and plume mathematical model which was designed to model this complex dispersion of PM10. Objectives This study aims to utilize the airGIS/OSPM to assess how the health impact is affected by the misclassifications of within city air pollution exposure. This helps assessing the feasibility of using the airGIS/OSPM in health studies. Methods The airGIS/OSPM was used for an urban area of Hong Kong, in the north west of Kowloon Peninsular for a period from 1998 to spring 2011. PM10 concentration’s were estimated at field measurement points, an EPD roadside monitoring site, and subjects in a subset of the elderly healthcare center cohort and for all building addresses in the modeled area. The airGIS/OSPM was validated by conducting a PM10 measurement campaign over the winter of 2010 to 2011. Also validation was conducted using the measurements of the Mong Kok EPD roadside monitoring station. A pilot study using the time stratified case-crossover analysis was conducted to explore the effects of using the airGIS/OSPM to express the subjects’ short-term outdoor residential exposure to PM10 on all cause mortality. AirGIS/OSPM PM10 estimates were compared with ambient concentrations obtained from the EPD monitoring network. The population mean exposure was calculated using the airGIS/OSPM estimated PM10 concentration at all building address points from 2007 to 2009 at the ground level and at middle building height level. The airGIS/OSPM estimate was used to identify spatial variation of PM10 within the study area. Results The airGIS/OSPM estimated well the measured PM10 concentration from the field measurement campaign and the EPD Mong Kok station. The airGIS/OSPM estimate and the ambient measure for EHC subject exposure both found an odds ratio for all cause mortality there was no difference from unity between case and control times. The airGIS/OSPM derived mean PM10 concentration at the middle height of each building was 54.8μg/m3 while that at the all EPD was 54.4μg/m3. At ground level the airGIS/OSPM PM10 estimate was 58.35μg/m3 while that at the EPD was 54.41μg/m3. Conclusion The misclassification of PM10 was negligible at the middle of buildings, but for people regularly working in ground level microenvironments are often exposed to PM10 concentrations that are higher than those measured at EPD monitors. It is feasible to use the airGIS/OSPM model to estimate PM10 exposure. The small spatial variation in exposure means the airGIS/OSPM may not be appropriate in assessing the short-term PM10 exposure, but due to the larger effect size it might be important in long-term exposure assessment. / published_or_final_version / Community Medicine / Master / Master of Philosophy

Objectives : To investigate the impacts of traffic related air pollution (TRAP) on children’s respiratory health, and to investigate the policies and regulations implemented in other countries and the suggestions from the World Health Organization (WHO) to tackle this problem. Methods and Results: Using relevant keywords, 122 articles were acquired from PubMed and 15 were from MEDLINE via EBSCO host respectively. The articles were published between 1980 to 2013; all of which had examined the impacts of TRAP on children’s respiratory health. After assessing inclusion and exclusion criteria, 9 articles were finally included in this systematic review. Differences in demographic characteristics were studied and compared to determine the association between TRAP exposure and respiratory health impacts on children aged between 1 and 18. Four cross-section surveys and five cohort studies were selected in this review. The association between TRAP exposure and differences in children’s respiratory impacts were demonstrated in all studies. Multiple outcome measures were used to examine changes of children’s respiratory health such as the decline in lung function, incidences of asthma and inflammatory responses. There were 4 out of 9 articles suggesting the decline in lung function was related to TRAP exposure; 5 out of 9 articles showed the relationships between incidences of asthma and inflammatory responses and TRAP exposure and 2 articles mentioned other respiratory symptoms; notably, wheezing and sneezing, runny and stuffed nose. This review finally summarized the results of selected articles stressing that children who lived close to roadway within a 500 meter radius from home, with an early exposure to air pollution in the first year of age and a frequent exposure to heavy road traffic and outdoor air pollutants would experience greater impacts on respiratory health. Conclusion: The positive association between the impacts on children’s respiratory health and TRAP exposure has been determined through this systematic review. Stricter emission control strategies and updated guidelines are required to regulate traffic emission and improve air quality in order to reduce harm and provide a better living environment for our next generations. / published_or_final_version / Public Health / Master / Master of Public Health

Environmental injustice has received high attention in the field of environmental studies. The concept of environmental justice is well defined within different academic disciplines. It refers to the rightness, fairness, and equity that a person in his own living environment is entitled to. In contrast, environmental injustice refers to the failure for one to receive the environmental justice that he is entitled to. Environmental injustice has been well substantiated by numerous international studies and evidenced in many countries overseas. A key question thus emerges: Is environmental injustice well evidenced in Hong Kong? Air pollution presents a major environmental challenge to the socially deprived communities both internationally and locally. Whilst the relationship between air pollution and social deprivation is well established internationally, given the strong evidence supporting the hypothesis that the socially deprived are exposed to more air pollution, the validity of such claim in the local context is not as obvious. Existing local studies investigating the relationship between air pollution and social deprivation are limited by, first, the lack of fine-grained air pollution data at a smaller geographical scale, which constrains the observation and conclusion of such hypothesis at a more refined geographical scale (Stern, 2003) and second, a stronger tendency to focus on the vulnerability of air pollution on different socio-economic spectrums (C. M. Wong et al., 2008). The current study aims to close the research gap by (a) developing a sophisticated methodology to enhance the collection and analysis of air pollution data at the Territorial Planning Unit, (b) examining the relationship between air pollution exposure and social deprivation at the TPU level, and (c) examining whether environmental injustice in relation to air pollution exists in Hong Kong. Our key research questions thus include the following: (1) Are the socially deprived in Hong Kong exposed to more air pollution? (2) Can we break through the existing methodological constraint and develop a brand new sophisticated air pollution data estimation methodology to interpolate air pollution at a smaller geographical scale? (3) If (1) is positive, would the exposure to more air pollution by the socially deprived in Hong Kong constitute the case of environmental injustice? A more sophisticated and accurate air pollution estimation methodology to estimate air pollution at a smaller geographical scale with the least root mean square error (RMSE) as compared to other key traditional models is introduced. The model identifies key spatial factors that affect the dispersion of air pollution in Hong Kong. By regression analysis, it is shown that the relationship between exposure to air pollution and social deprivation is positive and statistically significant. Both NO2 and PM10, the two major road-based pollutants, are positively correlated with the social deprivation index (for NO2: coefficient=0.4404 R= 0.6937, p<0.01; for PM10: coefficient = 0.4185, R = 0.6430, p<0.01). This leads to the conclusion that the socially deprived in Hong Kong are exposed to more air pollution, thus establishing the case of environmental injustice. This study has generated a key methodological breakthrough by developing a sophisticated air pollution estimation model that generates more accurate and fine-grained air pollution data at the TPU level – which was not previously available due to the limited number of air pollution monitoring stations in Hong Kong. This methodology allows the pursuit of social-economic air pollution study at a more refined geographical scale. The study strongly points to the existence of air-pollution related environmental injustice in Hong Kong. It calls for the Hong Kong Government to immediately address this under-researched and long neglected social-environmental problem, by formulating and implementing effective policies based on the fine-grained air pollution and socio-economic data, and the evidence generated from this study. / published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

In recent decades studies all around the world have shown an increasing trend of visibility degradation. In Hong Kong, the visibility has shown a deteriorating trend from 1968 to 2003 (Leung et. al 2004). The level of visibility has been proven to be related to the level of air pollutants causing air pollution. Therefore, visibility degradation is a sign of deteriorating air quality and a potential threat to human health. In addition, visibility degradation will blur the vista of the skyline that tourists are looking for in their trips. The degraded visibility will harm the tourists’ enjoyment at popular tourist sites such as the Peak, Hong Kong. This study aims at finding the standard of visibility violation of the lay public and the tourists in Hong Kong and their perception on visibility degradation. The study designs a questionnaire based on a judgement study on photograph of perception and justification of visibility standards by Pryor (1995) and the conceptual model of Sell et al. (1988) to unveil the reason behind the human standard on visibility degradation and the relationship between people’s background and their perception. The study suggests the standard of visibility violation is 4.5km in the Peak, Hong Kong and the standard varies from place-to-place while it is very much based on the environmental setting of the vista. A modified model based on the conceptual model by Sell et. al (1988) is introduced to explain the relationship between environmental change, individual, perception and their responses. It is deduced that human perception on visibility degradation will start when the environmental degradation exceeds the acceptance level of people. The finding proved that the standard of visibility violation could be determined. The standard would change according to a place-to-place format and poor visibility was interpreted according to the aesthetic characters and the aesthetic integrity of the vista. The demographic background of different individuals only determined the perception on visibility degradation but not the standard of visibility degradation. Meanwhile, according to the findings, a standard of low visibility based on either health concern or aesthetic concern and an early warning system of low visibility were proposed. / published_or_final_version / Geography / Doctoral / Doctor of Philosophy