Dr. Madan Kumar Piya, Oncologist, and Chairman/Director at National Hospital and Cancer Research Center, said that dust particles suspended in the air from construction works and vehicular emissions are the key causes of the increasing cases of respiratory and other health problems in Kathmandu. These particles can cause severe harm in human health by affecting lungs and blood circulation. Dr. Piya informed that air pollution constitutes 72 percent of risk for cardiovascular diseases and stroke, 14 percent for lung damage and 14 percent for cancer. 

The Kathmandu Valley air quality has been seriously degraded by dust, soot and emission from unleaded petrol and diesel in motor vehicles. People here use cloth masks or hold a handkerchief to cover their mouths when out on the streets, but these barely provide any protection. Larger particulate matters (PM) above 10 microns (PM 10) are trapped in the nose and mouth, but the finest and most deadly particles, PM 2.5, lodge themselves deep in the lungs. Using proper masks, educating people on the increasing risks of exposure to harmful air pollutants and regular check-ups are some of the precautionary measures that can be taken.

The cloth masks or surgical masks generally available in the market are not fully effective protection against air pollution, but using them is far better than not using masks. The use N95 mask however is more effective than the cloth mask.  The "N95" label stands for the mask’s ability to filter out at least 95% of airborne particles larger than 0.3 microns.  From all the test result N95 is good enough for filtering out most of the PM2.5 particles, but sensitive persons can consider using N99 version of these masks.