Data on ambient PM 10 levels from six locations in the Kathmandu Valley recorded by means of continuous sampling using low volume air samplers from October 2002 to March 2007 were used to investigate PM 10 concentration dynamics in the valley. This study analyzed daily patterns and dynamics of PM 2.5 concentrations in the Kathmandu Valley during three winters. The PM 2.5 data showed a daily repetitive cycle which represents influence of local air flow and dispersion and accumulation of air pollutants in the valley.

Particulate matters (PM10, PM 2.5, PM1), Black carbon, scattering properties of aerosol, gaseous pollutants (CO, C02, CH4 and water vapour), meterological parameters (temperature, humidity, pressure, wind speed, wind direction, solar flux and visibility) are being measured in capital city of Bhutan, Thimpu.

Particulate matters (PM10, PM 2.5, PM1), Black carbon, scattering properties of aerosol, gaseous pollutants (CO, C02, CH4 and water vapour), meterological parameters (temperature, humidity, pressure, wind speed, wind direction, solar flux and visibility) are being measured in Pasakha, Bhutan.

Particulate matters (PM10, PM 2.5, PM1), Black carbon, scattering properties of aerosol, gaseous pollutants (CO, C02, CH4 and water vapour), meterological parameters (temperature, humidity, pressure, wind speed, wind direction, solar flux and visibility) are being measured in Chitwan National Park area.