Volume 16, No. 8, August 2016, Pages 1854-1867 PDF(5.47 MB)
Temporal Assessment of NO2 Pollution Levels in Urban Centers of Pakistan by Employing Ground-Based and Satellite Observations
Muhammad Fahim Khokhar1,2, Hadiqa Mehdi1, Zain Abbas1, Zeeshan Javed1
1 Institute of Environmental Sciences and Engineering (IESE), National University of Sciences and Technology (NUST), Sector H-12 main campus, 4400, Islamabad, Pakistan
2 Visiting Scientist, Satellite Remote Sensing Group, Max-Planck-Institute for Chemistry, Mainz, Germany
- Down-wind areas are mainly affected by NO2 pollution.
- NO2 concentrations exceeded the Pak-NEQS levels at various locations of twin cities.
- Enhanced NO2 levels during December, 2013 were due to non-availability of CNG.
- Satellite underestimates NO2 columns as compared to car MAX-DOAS instrument.
This study presents the assessment of nitrogen dioxide (NO2) pollution within the twin cities of Islamabad and Rawalpindi by using car MAX-DOAS (Multi Axis-Differential Optical Absorption Spectroscopy) instrument during two different scenarios of with and without the availability of CNG (compressed natural gas) fuel. Information perceived from this study can be used to get an idea about recent air quality conditions of twin cities and its repercussions on ecological and human health. International air quality monitoring field campaigns were conducted during November 2012 and December 2013. Results showed different concentrations of NO2 (68.2, 74.25 and 93.65 ppb) at various locations of Islamabad and Rawalpindi cities, exceeded the Pak-NEQS levels of 42.5 ppb. High NO2 concentrations can be attributed to emissions from an oil refinery, traffic congestion and solid waste dump site along IJP road, and due to non-availability of CNG during December 2013. Results compared with OMI satellite observations exhibited that NO2 columns from OMI observations are largely underestimated.
CNG fuel; Car MAX-DOAS; Satellite validation; Air pollution; Pak-NEQS.