"Around the world, cities provide plenty of opportunities such as better education, advanced health treatment facilities, better employment, commerce, and trade as compared to rural areas. Therefore, more than half the world's people live and work together in urban communities, and it is projected that by the year 2030, three out of five people will stay in cities. The unrestrained and rapid growth of cities has also brought environmental degradation and causes many serious problems such as worsening of air quality, loss of natural habitat and species diversity, and increased human health risks associated with heat waves, noise and crowding. In most urban areas of developing countries, a variety of harmful air pollutants such as particulate matter, carbon monoxide, nitrogen and sulfur oxides, and polycyclic aromatic hydrocarbons are emitted from a variety of sources, mainly the burning of wood, fossil fuels and vehicular emissions, which adversely affects the health of human beings, animals, and other living creatures. In the urban environment, trees provide many economic, social, and environmental benefits to people, such as aesthetic beauty, improvement of property values, erosion prevention, storm water management, noise reduction, mental health development and crime reduction. In addition, trees help cool the air by shading surfaces that otherwise would absorb the sun's energy and then reradiate it out as heat. Trees also cool the ambient air. Urban trees on average reduce air temperatures on summer days by 2-4 °F, although in some circumstances the cooling effect can be even larger. Trees also sequester carbon, helping to mitigate climate change. The efficiency of atmospheric cleansing by trees in congested cities could be improved by planting more trees other than shrubs or herbs. Generally, avenue trees act as living filters to decrease pollution through absorption, accumulation, and detoxification. Trees remove gaseous air pollutants such as ozone, sulphur dioxide, and nitrogen dioxide mainly by uptake via leaf stomata, although some gases are removed by the plant surface. Once inside the leaf, gaseous air pollutants diffuse into intercellular spaces and may be absorbed by water films to form acids or react with inner leaf surfaces. Though some particles can be absorbed into the tree, most particles settle on the branches, leaves and twigs of plants and are washed out by the rain. Throughout the world, different advanced technologies such as smog-free towers in the Netherlands and adhesive roads for particulate matter in London have been applied. However, these technologies are extremely costly and unaffordable for countries like India and therefore the most eco-friendly and cost-effective way is plantation of tolerant tree species alongside highways, city streets, in parks, and in residential yards"--

The world's cities are choking on pollution from traffic and industry. With the health of over 1.6 billion people under threat, poor urban air quality is fast becoming one of them most pressing environmental problems of our times. Smog Alert examines the causes and scale of urban air pollution, identifying who is most at risk, and what particular health risks various pollutants pose. It then considers an effective framework for air quality management, so that national and city authorities can consider what pollution control polices and measures are needed to deliver healthy urban air quality, and to sustain it in the future. Having established the background and framework, the book examines the existing and alternative measures to monitor and combat the declining air quality. It assesses smog alert systems; the potential for cleaner car and fuel technology; sustainable traffic management and public transport policies; and methods of controlling both industrial and residential emissions. Detailed case studies illustrate the severity and breadth of the problem - from the first serious photochemical smogs in Los Angeles to the dire warning offered by Mexico City; and from London (the city which coined the word 'smog') to Athens' pollution phenomenon, the 'nefos'. Drawing on the lessons learned from past experience, Smog Alert provides a comprehensive analysis of how health air quality may yet be achieved in the world's cities.

This book contains twenty-one original papers and one review paper published by internationally recognized experts in the Atmosphere Special Issue "Recent Advances in Urban Ventilation Assessment and Flow Modelling", years 2017–2019. The Special Issue includes contributions on recent experimental and modelling works, techniques, and developments mainly tailored to the assessment of urban ventilation on flow and pollutant dispersion in cities. The study of ventilation is of critical importance, as it addresses the capacity with which a built urban structure is capable of replacing the polluted air with ambient fresh air. Here, ventilation is recognized as a transport process that improves local microclimate and air quality and closely relates to the term “breathability”. The efficiency with which street canyon ventilation occurs depends on the complex interaction between the atmospheric boundary layer flow and the local urban morphology. The individual contributions to this Issue are summarized and categorized into four broad topics: (1) outdoor ventilation efficiency and application/development of ventilation indices, (2) relationship between indoor and outdoor ventilation, (3) effects of urban morphology and obstacles to ventilation, and (4) ventilation modelling in realistic urban districts. The results and approaches presented and proposed will be of great interest to experimentalists and modelers, and may constitute a starting point for the improvement of numerical simulations of flow and pollutant dispersion in the urban environment, for the development of simulation tools, and for the implementation of mitigation strategies.

Containing the proceedings of the 23rd International Conference on Modelling, Monitoring and Management of Air Pollution, this book is the latest in a well established series. It addresses various aspects of a topic that is of considerable worldwide concern due to its known impact on health and the environment. The need to balance concern for the environment with the demand for generating economic growth makes air pollution a particularly challenging problem. Further complicating the picture, the widespread nature and effects of air pollution make it an issue that requires not just local but global attention and cooperation. Science can help us identify the nature and scale of air pollution impacts. It is therefore essential in guiding government decisions regarding the most appropriate and effective regulations. As we learn ever more about the basic science of air pollution, and its application, we are better able to predict, assess, and mitigate its effects, locally, regionally, nationally, and internationally. This book presents advances in our knowledge of the science of air pollution. Topics covered include Air Pollution Modelling; Air Pollution Mitigation; Air Pollution Management; Aerosols and Particles; Emission Studies; Exposure and Health Effects; Indoor Air Pollution; Monitoring and Measuring; Case Studies; Emerging Technologies; Power Generation and Air Pollution; Incineration Plant Studies; Air Pollution Chemistry; Global and Regional Studies; Policy and Legislation.

"This publication offers practical advice and inspiration for ensuring that nature in the city is more than infrastructure--that it also promotes well-being and creates an emotional connection to the earth among urban residents. Divided into six parts, the Handbook begins by introducing key ideas, literature, and theory about biophilic urbanism. Chapters highlight urban biophilic innovations in more than a dozen global cities. The final part concludes with lessons on how to advance an agenda for urban biophilia and an extensive list of resources."--Publisher.

An analysis of trees in New York City reveals that this city has about 5.2 million trees with canopies that cover 20.9 percent of the area. The most common tree species are tree of heaven, black cherry, and sweetgum. The urban forest currently stores about 1.35 million tons of carbon valued at $24.9 million. In addition, these trees remove about 42,300 tons of carbon per year ($779,000 per year) and about 2,202 tons of air pollution per year ($10.6 million per year). The structural, or compensatory, value is estimated at $5.2 billion. Information on the structure and functions of the urban forest can be used to improve and augment support for urban forest management programs and to integrate urban forests within plans to improve environmental quality in the New York City area.