Source Sector Contributions to Aerosol Levels in Pakistan

Abstract Urban air pollution in Pakistan is a serious challenge and it causes significant damage to human health and ecosystems. This paper presents a modelling study using the Weather Research and Forecasting Model coupled with Chemistry (WRF-Chem) to simulate the spatial distributions and temporal variations of aerosol concentrations over Pakistan, focusing on contributions of domestic emission sectors (transport, industry, residential, and energy) to mass concentrations of sulfate (SO42-), nitrate (NO3−), ammonium (NH4+), black carbon (BC), and organic carbon (OC) during the months of January, April, July, and October in 2010. Sensitivity studies indicate that, averaged over January, April, July, and October of 2010, energy and industry sectors have the largest contributions to SO42- concentrations, each of which contributes about 10%–20% to SO42- over the polluted eastern Pakistan. The contributions from residential and transport sectors to NO3− concentrations reach 40%–50% in central Pakistan. The residential sector has the highest contribution of 50%–80% to BC and OC loading in northeastern and southern Pakistan. Examination of sector contributions to aerosol levels in Lahore, the most polluted city in Pakistan, suggests that reductions in emissions in the residential sector should be an efficient measure for improving particulate matter air quality in this region.

[1]  M. Qadir,et al.  Characteristics of the aerosol particulates in the atmosphere in an urban environment at Faisalabad, Pakistan , 2006 .

[2]  M. Mansha,et al.  Characterization and source apportionment of ambient air particulate matter (PM2.5) in Karachi. , 2012, The Science of the total environment.

[3]  Shoaib Shafique,et al.  Particulate matter (PM2.5) concentration and source apportionment in lahore , 2009 .

[4]  Chang-Hoi Ho,et al.  Parameterizations for Cloud Overlapping and Shortwave Single-Scattering Properties for Use in General Circulation and Cloud Ensemble Models , 1998 .

[5]  G. Grell,et al.  Evolution of ozone, particulates, and aerosol direct radiative forcing in the vicinity of Houston using a fully coupled meteorology‐chemistry‐aerosol model , 2006 .

[6]  Georg A. Grell,et al.  Fully coupled “online” chemistry within the WRF model , 2005 .

[7]  E. Mlawer,et al.  Radiative transfer for inhomogeneous atmospheres: RRTM, a validated correlated-k model for the longwave , 1997 .

[8]  M. V. Ramana,et al.  Characterization of the seasonal cycle of south Asian aerosols: A regional‐scale modeling analysis , 2007 .

[9]  Oliver Wild,et al.  Fast-J: Accurate Simulation of In- and Below-Cloud Photolysis in Tropospheric Chemical Models , 2000 .

[10]  Thomas Blaschke,et al.  Source Apportionment and Characterization of Particulate Matter (PM10) in Urban Environment of Lahore , 2014 .

[11]  Jerome D. Fast,et al.  Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) , 2008 .

[12]  W. MacNee,et al.  Particulate air pollution and acute health effects , 1995, The Lancet.

[13]  J. Lamarque,et al.  Description and evaluation of the Model for Ozone and Related chemical Tracers, version 4 (MOZART-4) , 2009 .

[14]  Steven J. Ghan,et al.  Impact on modeled cloud characteristics due to simplified treatment of uniform cloud condensation nuclei during NEAQS 2004 , 2007 .

[15]  H. D. Orville,et al.  Bulk Parameterization of the Snow Field in a Cloud Model , 1983 .

[16]  Leonard K. Peters,et al.  A new lumped structure photochemical mechanism for large‐scale applications , 1999 .

[17]  I. Shahid,et al.  Seasonal Variations of Aerosols in Pakistan: Contributions of Domestic Anthropogenic Emissions and Transboundary Transport , 2015 .

[18]  M. Salam,et al.  An assessment of air quality in Karachi, Pakistan , 1994, Environmental monitoring and assessment.

[19]  Steven J. Ghan,et al.  Coupling aerosol-cloud-radiative processes in the WRF-Chem model: Investigating the radiative impact of elevated point sources , 2008 .

[20]  Philip K. Hopke,et al.  Source Apportionment of the Atmospheric Aerosol in Lahore, Pakistan , 2010 .

[21]  Liaquat Husain,et al.  Gaseous and aerosol pollutants during fog and clear episodes in South Asian urban atmosphere , 2008 .

[22]  D. Dockery,et al.  An association between air pollution and mortality in six U.S. cities. , 1993, The New England journal of medicine.