OPEN ACCESS

Articles online

Seasonal Variations of Aerosols in Pakistan: Contributions of Domestic Anthropogenic Emissions and Transboundary Transport

Category: Air Pollution Modeling

Volume: 15 | Issue: 4 | Pages: 1580-1600
DOI: 10.4209/aaqr.2014.12.0332
PDF | RIS | BibTeX

Muhammad Zeeshaan Shahid1,2, Hong Liao 1, Jianping Li3, Imran Shahid4, Arifa Lodhi5, Muhammad Mansha5

  • 1 State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmosphere Physics Chinese Academy of Sciences, Beijing 100029, China
  • 2 University of the Chinese Academy of Sciences, Beijing 100049, China
  • 3 College of Global Change and Earth System Science (GCESS), Beijing Normal University, Beijing 100875, China
  • 4 Institute of Space Technology, Islamabad, Pakistan
  • 5 Space and Upper Atmosphere Research Commission (SUPARCO), (null), Pakistan

Highlights

We present the first regional modeling study of aerosols over Pakistan.
Simulated PM2.5 levels in Pakistan are the highest in autumn and lowest in summer.
Seasonal variations of SO42–, NO3, NH4+, BC and OC over Pakistan are examined.
Transboundary transport contributes 10–40% to PM2.5 levels in northeastern Pakistan.


Abstract

Air pollution has become a serious challenge for developing countries like Pakistan. Very scarce information is available regarding pollution levels in this geographic region. This study presents the first modelling work to simulate the spatial distribution and temporal variation of aerosol concentrations over Pakistan by using the Weather Research and Forecasting Model coupled with chemistry (WRF-Chem). Simulated aerosols species include sulfate, nitrate, ammonium, organic carbon, black carbon, and PM2.5 (particles with a diameter of 2.5 μm or less), which are evaluated against ground-based observations and satellite measurements. In year 2006, simulated PM2.5 concentrations averaged over northeastern Pakistan (71–74.5°E, 28–34°N) are 55, 48.5, 31.5, and 98 µg/m3 in January, April, July, and October, respectively. The simulated highest PM2.5 concentration in October results from the relatively low temperatures that favor nitrate formation as well as the lowest precipitation that leads to the smallest wet deposition of all aerosol species. The simulated lowest concentration of PM2.5 in July can be attributed to the largest precipitation associated with the South Asian summer monsoon. Sensitivity studies show that transboundary transport contributes to PM2.5 aerosol levels in northeastern Pakistan by 10–20% in January and April and by 10–40% in July and October of year 2006. Wind over India and Pakistan is found to be the major meteorological parameter that determines the transboundary aerosol transport.

Keywords

WRF-Chem Aerosols in Pakistan Seasonal variations


Related Article

Evaluation of δ13C in Carbonaceous Aerosol Source Apportionment at a Rural Measurement Site

Johan Martinsson , August Andersson, Moa K. Sporre, Johan Friberg, Adam Kristensson, Erik Swietlicki, Pål-Axel Olsson, Kristina Eriksson Stenström

Analysis of Long-Range Transport Effects on PM2.5 during a Short Severe Haze in Beijing, China

Weilin Yang, Guochen Wang, Chunjuan Bi
Volume: 17 | Issue: 6 | Pages: 1610-1622
DOI: 10.4209/aaqr.2016.06.0220
PDF
;