chapter - 1 introduction - Meghalaya State Pollution Control Board

Hills Cement Co. Limited.
speed, wind direction, relative humidity, rainfall and temperature in order to
generate site-specific data. The data generated is computed to obtain windroses
of the area. The wind direction describes three quadrants of 24-hour
time period. The wind roses plotted for the wind directions recorded during
the study period from December 2007 to March 2008 are presented. The
study period from December 2007 to March 2008 recorded ambient air
temperatures minimum and maximum as 11Û&DQGÛ&UHVSHFWLYHO\
Relative Humidity (RH)
The region generally experiences tropical climatic condition throughout the
year except during winters. The lowest relative humidity recorded of the study
area was 60% and highest as 90% and average humidity, yearly was found
70%. Day times experience higher humidity levels as compared to nights.
Average rainfall is 3042 mm. The duration of rainfall is about 6 months in a
year. It is observed that rainfall is occurred towards the end of March, 2008.
Wind
The wind direction is WE. The basic wind velocity as per IS: 875-1987, Part
III, 4 Km/hr can be considered for designing the civil structures. The average
wind speed ranged from 0.6 m/s during the study period.
Wind pressure:
0-8m 900 kN/m 2
8-20m 1,400 kN/m 2
Above 20m 1,950 kN/m 2
Table-3.8 Environmental Attributes & Frequency of Monitoring
Attribute Parameters Frequency of Monitoring
Ambient Air
Quality
Meteorology
Water Quality
SPM, RSPM
SO 2 , NOx, CO, HC
Surface: Wind speed, Wind
direction, Temperature,
Relative humidity and Rainfall
Physical, Chemical and
Bacteriological Parameters
24 hourly samples twice a
week during study period.
8 hourly samples twice a
week during study period.
Surface: Continuous
monitoring station for entire
study period on hourly
basis and also data
collection from secondary
sources.
Once during the study
season
Pollution Control Consultants (India) Pvt. Ltd. 48