THE INFLUENCE OF METEOROLOGICAL CONDITIONS ON PM10 CONCENTRATIONS IN KATHMANDU VALLEY

Air pollution is a problem in Kathmandu, Nepal. Particulate matter concentrations often exceed threshold values at which human health is severely affected. The problem is serious since it is in the valley topography wherein the meteorological parameters role is significant. This study addresses the linkages between meteorological processes and air pollution in the lower atmosphere of the Kathmandu Valley. The study establishes influence of meteorological conditions like temperature, rainfall, humidity, atmospheric pressure, wind direction and speed with elemental concentrations of PM10 in Kathmandu Valley.Government of Nepal has established permanent air monitoring stations in the valley and a continuous PM10 data is available on the public domain. The data relating to average daily temperature, rainfall, humidity, atmospheric pressure, wind speed and wind direction recorded in Tribhuvan International Airport was used for analysis. The mean association of PM10 levels and meteorological parameters during the period of March 2003 and December 2005 is established. Pearson's coefficient of correlation was applied to study the association between PM10 and meteorological variables. The atmospheric pressure, wind velocity and humidity was found to be significant factors compared to others influencing PM10. Increase of rainfall and humidityhas negative correlation with average PM10 concentration in Kathmanduvalley. The study also infers that the wind speed and atmospheric pressure inducing increment of average PM10 concentration in Kathmandu Valley.