Spatio-temporal variations of lower tropospheric pollutants and their relation with meteorological factors in Karachi, Pakistan

Abstract

Despite being one of the most populated cities globally, the air quality of Karachi is hardly ever comprehended. The present paper investigates the outdoor concentrations of 10 air pollutants, viz. NO, NO2, NOx, SO2, CO, O3, CH4, methane carbon, non-methane hydrocarbons, and total hydrocarbons at three different city sites, viz., Sohrab Goth, Defense Housing Authority, and North Nazimabad. The results demonstrate that these pollutants severely affected the city's air quality. The annual mean concentrations of both NO2 and SO2 exceeded the WHO guidelines at some study sites. The city experiences varied concentrations of major air pollutants because three types of fuel, viz. diesel, gasoline, and compressed natural gas, operate the motor vehicles in this conurbation. The study also correlates the various air pollutants with each other and with various meteorological factors. All the three oxides of nitrogen are statistically associated at all three sites with one another, with SO2 at Defense Housing Authority, with CO at North Nazimabad, and with meteorological factors at Sohrab Goth and Defense Housing Authority. Carbon monoxide is statistically associated with the meteorological factors only at North Nazimabad. The study suggests that higher air pollution in the city is due to the adoption of lenient vehicular emission standards because stringent emission standards cannot be adopted due to the non-availability of low or zero sulfur fuel. Moreover, ineffective regulation of exiting standards also contributes to higher vehicular emissions in the city.

Investigating the Opportunities to Improve the Thermal Performance of a Case Study Building in London

“…Inordertobuildhighefficiencybuildings,theamountoftheglazingareatotheenvelopeshould beconsideredwhichplaysthemostimportantroleinsolargainswithinthebuildings.Theradiated solarenergytotheEarthisdividedin3parts:4%ultra-violateradiationwhichthehumanisunable torecognise,47%canbeseenasthenaturallightbyhumaneyesandnearly50%ofthisenergyis infrared radiation (Ahmed, et al, 2017). Although this radiation affects the heat gains, utilizing naturallightofthesuncanreduceusingtheamountofartificiallightingproducedbythelightsand consequentlyreductioninthecoolingloadaswell (Bodart&Herede,2002).…”