Characteristics of ventilation coefficient and its impact on urban air pollution

Characteristics of air pollutant dispersion around a high-rise building

“…Poor quality air promotes the spread of respiratory and other communicable diseases (Portney and Mullahy, 1990), and even results in serious cardiovascular diseases (Brook et al, 2004), particularly for the very young and very old, and people with chronic diseases and those with immune deficiency. The alarming progressive degradation of air quality worldwide is attributable to the growth of manufacturing and resource industry in East and South Asia to meet the burgeoning demand for goods and services by a growing affluent population, a lack of control of air pollution caused by fossil fuel combustion to meet the demand for energy and the inadequacy of air ventilation in urban area where a large proportion of the world population reside (Alejo et al, 2010;Lu et al, 2012). Evidently, building arrays and street canyons have an undesirable impact on the ground level wind flow, air ventilation within the urban fabric, as well as the dispersion of air pollution; however windestructure interaction which governs the effects of buildings on atmospheric flow is often not properly considered when making urban development and urban planning decisions (Abd Razak et al, 2013).…”

Atmospheric ventilation corridors and coefficients for pollution plume released from an Industrial Facility in Ile-Ife Suburb, Nigeria

“…Contd. ) obtained during nighttime by Lu et al (2012) are also the same here. Using wind speed at mean MLH, Ashrafi et al (2009) also estimated V-co values between 7 900 to 22 400 for Tehran, Iran.…”

“…The ventilation coefficient V-co (m 2 s -1 ) which is a measure of atmospheric transport and dilution of gaseous pollutants species in air within the atmospheric boundary layer was estimated as a product of the parameterized MLH (m) and mean wind (ms -1 ) near the ground surface as in Equation 4 (Ashrafi et al, 2009;Lu et al, 2012). For the purpose of this work, wind speed measured at 5.5 m near scrap-iron factory has been used in order to fully represent the meteorological conditions at the point of release of the pollution plume.…”

“…The results obtained in this study were similar and comparable to previous study. For instance, Lu et al (2012) investigated the characteristics of V-co and its impacts on air pollution in Changshe, China using mean wind speed at 10 m and predictions of MLH by HYSPLIT model. Diurnal trend observed wind speed (1.1 to 3.5 ms 01 112 79 24 216 79 43 33 134 02 93 58 22 155 57 35 35 109 03 81 30 39 110 51 49 13 1...…”

“…A variation up to about 10% under unstable conditions, 50% under neutral conditions, and about 90% under stable conditions could occur. As such, estimates of the atmosphere's dispersive capacity (ventilation coefficient) and ventilation corridors for toxic gaseous pollutants released into the ambient environment from industrial facilities are required for assessment of potential impacts of elevated concentrations of such releases (Genc et al, 2010;Lu et al, 2012).…”