chapter - 1 introduction - Meghalaya State Pollution Control Board

Hills Cement Co. Limited.
Dispersion Parameters
Dispersion parameters and for open country conditions (Briggs, 1974) are
used as the project is located on a flat terrain in a rural area. Atmospheric
dispersion coefficients vary with downwind distance (x) from emission
sources for different atmospheric stability conditions. (CPCB –
PROBES/70/1997-98)
Mixing Height
As site specific mixing heights were not available, mixing heights based on
CPCB publication, “SPATIAL DISTRIBUTION OF HOURLY MIXING DEPTH
OVER INDIAN REGION”, PROBES/88/2002-03 has been considered for
Industrial Source Complex model to establish the worst case scenario.
Meteorological Data
Data recorded at the continuous weather monitoring station on wind speed,
direction, and temperature for the monitoring period was used as
meteorological input.
In the present case model simulations have been carried using the triple joint
frequency data. Short-term simulations were carried to estimate
concentrations at the receptors to obtain an optimum description of variations
in concentrations over the site in 20-km radius covering 16 directions.
The incremental concentrations are estimated for the monitoring period. For
each time scale, i.e. for 24 hr (short term) the model computes the highest
concentrations observed during the period over all the measurement points.
The maximum incremental GLCs due to the proposed cement plant, and
captive thermal power projects together for SPM, SO 2 and NOx are
superimposed on the maximum baseline SPM, SO 2 and NOx concentrations
recorded at the monitoring locations during the field monitoring period winter
2007-2008. The incremental concentration due to operation of thermal power
plant, cement plant and their combined cumulative concentrations (baseline +
incremental) after implementation are tabulated below in Table- 4.1, Table
4.2 and Table 4.3 respectively. The maximum GLCs for SPM, SO 2 and NOx
after implementation of the proposed project are likely to be within the
prescribed NAAQ standards for Rural and Residential areas.
Pollution Control Consultants (India) Pvt. Ltd. 87