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DEVELOPMENT OF A GRID-BASED EMISSION INVENTORY AND A SOURCE-RECEPTOR MODEL FOR DHAKA

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Authors :

Tanjina Afrin

Stamford University Bangladesh, Dhaka, Bangladesh

 

M. Ashraf Ali, S. M. Rahman And Z. Wadud

Bangladesh University Of Engineering And Technology, Dhaka , Bangladesh

 

Presented by

S. M. Rahman

 

 

Back Ground

 

  • Dhaka is the capital city of Bangladesh,
  • Around twelve million people and has a population density of about 20,000 people per km2
  • One of the most polluted cities of the world

                - Air pollution

                - River pollution

                - Soil pollution

                - Noise pollution

 

  • Air pollution is the most threatening problem now-a-days.
  • Economic cost associated with air pollution related environmental degradation is about 1.1% of GDP
  • 15,000 premature deaths, as well as several million cases of pulmonary, respiratory and neurological illness
  • Both PM10 and PM2.5 concentrations exceed the WHO guidelines
  • Also exceed the national standards of annual PM10 and PM2.5 by a factor of over two
  • Recently, the Government introduced a number of initiatives

                - ad-hoc basis

                - some improvements

  • But there is a lack of benefit modeling to support these decisions
  • For addressing the air quality problem,

               - Development of an emission inventory and

               - Subsequent prediction of ambient concentration is essential.

 

AIR QUALITY OF DHAKA

 

 

 

 

 

OBJECTIVE

 

  • To develop a grid-based emission inventory for Dhaka City.
  • Development of Source-Receptor Matrix (SRM)
  • To show the applicability of SRM, a case study is presented to generate ambient concentration of Particulate Matter (PM10, PM2.5) for the most critical month for air pollution i.e. March.

 

MODEL DOMAIN

 

  • Domain is between 2330’0” to 246’0” N 9018’0” to 9048’0” E
  • Areas outside the city also contribute. So domain is extended in both north and south direction.
  • The model area is divided into 200 grids of 0.03 0.03, which is approximately 3 km 3 km.

 

 

 

DEVELOPMENT OF EMISSION INVENTORY

 

Emission from each of following source groups has been estimated separately and finally they have been summed up to estimate the total emission.

  • Traffic Emission
  • Road Dust
  • Brick Kiln Emission

 

 

 

 

 

SOURCE RECEPTOR (S-R) MODEL

 

  • Indication of the relationship between the source the receptor

                - Defined as change in concentrations in a receptor grid per unit change in emissions in the source grid

                - S-R matrix, also known as transfer coefficient/matrix

                - Helps in calculation of ambient concentration if emission is known and vice-versa

 

ELEMENTS OF SOURCE RECEPTOR MATRIX (SRM)

 

 

 

SPATIALVARIATION OF PERTICULATE MATTER (PM10)

 

 

 

SPATIALVARIATION OF PERTICULATE MATTER (PM2.5)

 

 

 

 

PERTICULATE MATTER (PM) CONCENTRATION

 

 

 

SPATIALVARIATION OF PERTICULATE MATTER (PM10 & PM2.5)

 

  • Both PM10 and PM2.5concentration varies widely
  • The brick kiln emissions take place outside the main city.
  • The traffic emissions are higher in the Dhaka city area.
  • Emissions from re-suspended road dust are relatively higher than that of vehicular emission.
  • Emission load of brick kiln is very high in comparison to the traffic emissions
  • Average concentration of PM10 and PM2.5 have been found 118 μg/m3 and 67 μg/m3 respectively.
  • Both average concentrations exceed the 24- hour average concentration of Bangladesh standards.
  • The concentration also exceeds the Bangladesh standard for annual average concentration.

 

COMPARISON WITH DATA  AT CAMS

 

 

COMPARISON OF CONTRIBUTIONS FROM DIFFERENT SOURCES

 

 

 

SUMMERY OF THE STUDY

 

  • An emission inventory has been developed for Dhaka city and its surrounding areas, incorporating three major sources: traffic emission, road dust and brick kiln emission.
  • Concentrations for both PM10 and PM2.5 have been estimated using an S-R model.
  • At March, both concentrations exceed the national standards for 24-hours and annual average.
  • Road dust is found to be dominant source for particulate pollution in Dhaka city, followed by brick kiln and traffic emissions.

 

 

FUTURE WORKS

 

  • Other potential sources of emission should be incorporated in future.
  • Works are currently underway on
    • Predictions of ambient concentrations throughout the year and comparison with available data.
    • Analysis of uncertainty of different parameters used in the simulations.

 

Source: epa.gov

 

 


 

 

 

 

 

 

 

 

 

 

 

 

 

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