Effectsof Urban Design and Planning on Air Quality”6.5 million Peopleare dying annually from air pollution and 92 per cent of the world’s populationsare living in places where levels exceed recommended limits” says a reportby United Nations. The abovestatement rings an alarm, immediately making us think what could have been thevarious reasons for this state of affairs. Air pollution, other than being themajor contributor to global warming, has also paved way for harmful PublicHealth conditions globally. Though there are several contributors to airpollution, Urban Design and Planning of a city, to a large extent determinesair quality in urban areas, particularly in the developing countries.
To actively reduce poor air quality in cities,we need to understand and study the urban climate before we design our urbanspace. The shape of acity and distribution pattern of land use affects air quality and its healthimpact. The urban shape determines, locations of emissionsources, where people predominantly spend their time and commute. Air pollutionin urban areas is characterized mainly by pollutants such as Carbon Monoxide,Nitrogen Dioxide, Ozone and Particulate Matter.
Design factors that affect airquality in an urban area includes Density, Land Use Mix ,TransitAccessibility, pedestrian-environmentand patterns of development. Ambient air pollutant concentrations are distributednon–uniformly in urban areas, creating hot spots mostly in central businessdistrict, traffic intersections and signalized roadways (Kandlikar, 2007). Street- level air pollution is very critical in determiningthe air quality in urban areas.
Concentrationsin streets are generally higher than in urban background sites due to theproximity to high traffic density and poor dispersion conditions 8.Therefore, pollutant concentrations in these street canyons are likely toexceed air quality standards. Factors that affect street level air pollutionare EmissionLevels, proximity to Road,AirCirculation ( winds, breezes, inversions), andsinks. ( Sprin et al,1986).
Vehicles emit fewer air pollutants at even speeds, when engines operate moreefficiently, and emit greater quantities in stop-and-go traffic and while idlingat stoplights. Under calm conditions, the concentration of air pollutants can thereforevary significantly along a single street or between two streets a block apart. CarbonMonoxide emissions, for example, tend to peak at intersections, where concentrationsmay be ten times higher in the Intersection than at a point eighty meters furtherdown the road (Horowitz , 1982). This can be evidently seen as a huge urbanplanning problem in developing countries.
New Delhi, India is one significant example,to illustrate how various facets of Urban Planning like Land Use, built area,lack of sufficient green cover and transportation planning are majorcontributors among various other myriad reasons to the city’s current state ofair quality emergency. Though there hasbeen efforts from policymakers in creating a framework to combat this issue,unifying people’s efforts through education and awareness is one area thatwould make a huge difference if worked upon. Green infrastructure ; thatincludes green building technologies, green construction materials , efficient waste generation and management systems, wouldeffect the urban design in a positive way, towards achieving a goal for cleanerair.
( Rizwan et al, 2013). Though on one hand simplest and proven to improveair quality has always been associated to reducing the pollutants emitted fromthe sources , the serious impacts on human health address the importance of amore holistic approach for improving the urban air quality. It is importantthat we all work together to improve air quality in cites and urban designersand planners find ways to improve existing systems as well as bring forthinnovations in the field of Green Infrastructure. After all, clean air for thisplanet’s residents is indeed a primary requisite for public health andwell-being.