Air pollution appears to be a current issue in Bhutan. Sources of pollution include vehicles, forest fires, bukharis, and industrial waste, among others. Thimphu's topography - a high-altitude city surrounded by mountains - can create a pollution disaster if the area is prone to thermal inversion.
While relatively large particles can usually be filtered by the nose and throat, particles smaller than 10 micrometers can end up in the lungs and cause serious health problems.
The National Environmental Council (NEC) measures of particles with size 10 micrometers or less (PM10) and posts the 24-hour readings on its home page. BBS also shows the daily PM10 numbers during news hour on the bottom right corner of the TV screen, although I found their display rather difficult to read.
What I could not find on the NEC website are historical numbers. Is pollution increasing? Is it decreasing? Does it change with the seasons? What was the worst day? All these questions are impossible to answer without historical data.
I decided to start collecting this information using an automatic program that copies the daily readings into an online spreadsheet. This spreadsheet is updated daily. This information available publicly on our new Air Pollution page, which you can access from the top navigation bar.