Ambient Air Quality Evaluation: A Comparative Study in China and Pakistan.

Vehicle and industrial emissions are responsible for a considerable share of urban air pollution concentrations. We conducted a comparative study in Dalian, China and Faisalabad, Pakistan to reevaluate NO2, SO2, and CO concentrations. Our study was conducted over the course of one year at different stations in both cities, and measured values were compared with ambient air quality standards such as NEQS-Pakistan, NAAQSUSEPA, CNAAQS-China, and global standard WHO. The NO2 concentrations in Faisalabad varied from 185- 262 μg/m³, whereas it was in the range of 44-133 μg/m³ in Dalian. The SO2 concentration was found in the range of 66-190 μg/m³ and 56-128 μg/m³, while CO varied from 5.4-22.3 mg/m³ and 0.3-2.8 mg/m³, respectively, in Faisalabad and Dalian. The annual average NO2, SO2, and CO concentrations were below the permissible limits in Dalian; however, the measured values were considerably higher in Faisalabad. Our results are the first to compare air quality of two countries at different stations and highlight the possibility of reducing air pollution by comparing conditions. [ABSTRACT FROM AUTHOR]