National Standards for

Ambient Air Quality, Industrial Emission, Workplace Emissions and Noise levels for Bhutan

Ambient Air Quality Standards (Maximum permissible Limits in µg/m³)

Parameter	Industrial Area	Mixed Area*	Sensitive Area**
Total Suspended Particulate Matter 24 Hour Average Yearly Average	500 360	200 140	100 70
Respirable Particulate Matter (PM 10) 24 Hour Average Yearly Average	200 120	100 60	75 50
Sulfur Dioxide 24 Hour Average Yearly Average	120 80	80 60	30 15
Nitrogen Oxides 24 Hour Average Yearly Average	120 80	80 60	30 15
Carbon Monoxide 8 Hour Average 1 hour Average	5000 10,000	2000 4000	1000 2000

* Mixed Area means area where residential, commercial or both activities take place,

** Sensitive Area means area where sensitive targets are in place like hospitals, schools, sensitive ecosystems.

Industrial Emissions: Maximum Limits for Pollutants (mg/Nm³)

	Maximum Limits for Pollutants (mg/Nm^3)
Industrial Type by Technology	SPM	SO2	NOx	CO
Lime Kilns	150	100	100	50
Arc Furnace, Induction Furnace	150	100	100	50
Tapping Fume Stack	150	-	-	-
Coal fired, Oil fired and Wood fired Boiler	150	100	100	50
Horizontal/Rotary Kiln, Vertical Shaft Kiln and other Kilns	150	100	100	50
Other Technologies: for sectors that are not covered in the above sections	150	100	100	50

Workplace Emissions for 8 hour average

Parameter	Standard
Total Suspended Particulate	10mg/m^3
Respirable Particulate Matter	5mg/m^3
Sulfur Dioxide	1mg/m^3
Nitrogen Oxides	1mg/m^3
Carbon Monoxide	5mg/m^3

Noise Level Limits

Industrial Area		Mixed Area		Sensitive Area
Day*	Night*	Day	Night	Day	Night
75 dB(A)	65 dB(A)	65 dB(A)	55 dB(A)	55 dB(A)	45 dB(A)

Note: All the values are maximum values

* Day time is from 0600 hours to 2200 hours (human activities)

** Night time is from 2200 hours to 0600 hours (no human activities)

Maximum value allowed in workplace in any point of time is 75 dB(A).