5.1. Atmospheric transport of air pollutants
As air pollution has not been a problem in Bhutan until recently, there has been no study conducted to assess atmospheric transport of air pollutants.
5.2. National Air Quality Criteria and Standards
According to the Bhutanese Environmental Objectives and Standards (NECS 1999), the required particulate removal from the kiln and clinker cooler exhausts is 99.9% of all particulates and 99.5% of particulates less than 10 microns in size (PM10). Such levels are to be achieved during at least 95% of the plant's operating time. These requirements correspond to an emission standard of 50m g/m3 under full load capacity.
Ambient air quality objectives to be achieved at the plant boundary, depending on the land use beyond the boundary are as given below:
Table 12. Recommended Ambient Air Quality Objectives for Cement Plants
in Bhutan
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| Suspended Particulates |
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| Oxides of Sulphur (SOx) |
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| Oxides of Nitrogen (Nox) |
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Source: Ambient/discharge environment quality NEC, 1999
For suspended particulate the limits noted above are 24-hour maximum values only. In addition, annual geometric mean value of 80 m g/m3 for rural/residential areas and for industrial areas 150 m g/m3 must not be exceeded.
5.3. Control options
Table 13. Control options applied
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Control option applied |
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| Vehicles | Emission standard and ban of re-conditioned diesel cars. | This control was used as pilot study, and the results are not yet concluded. |
| Manufacturing Industries | Pollution standard prescribed by NECS/MTI | N.A |
| Mining | Pollution standard prescribed by NECS/MTI | N.A |
| Agriculture | Pollution standard prescribed by NECS/ MOA | N.A |
| Forest Fire | Fines and Penalties and awareness | Forestry Services Division |
| Domestic Emission | Alternative sources of fuel like Improved stove and biogas support program, rural electrification. | This control option is gaining momentum as smokeless stove and electric stoves are encouraged |