Woraphan Puchanyaporn. Development of empirical modeling for nitrogen dioxide prediction in Thailand . Master's Degree(Appropriate Technology for Resources Development). Mahidol University. : Mahidol University, 2006.
Development of empirical modeling for nitrogen dioxide prediction in Thailand
Abstract:
Oxides of nitrogen (NOx), a group of significant pollutants, are generally in
form of nitric oxide (NO) and nitrogen dioxide (NO2). They affect directly and
having an indirectly human health and environment as well as important role as a
precursor of ozone formation in the troposphere which consequently enhances air
pollution. Therefore this study aimed to identify the characteristic of NOx and NO2
in temporal variations such as diurnal, monthly and annual distribution including
their relationships between the NOx and NO2 using an empirical model. Hourly data
of NOx and NO2 from 13 air quality monitoring stations collected by the Pollution
Control Department during 1999 to 2003 were used as representative of roadside
and urban background areas in Bangkok and regional areas of Thailand.
The characteristics of NOx and NO2 for roadside areas at Dindaeng Housing
Authority in Bangkok and Yupparaj Wittayalai School in Chiang Mai and for
general areas at National Housing Authority in Bangkok, City Hall in Samutprakan
and Public Service Centre in Chiang Mai found the bimodal distribution of diurnal
variation which most-likely affected by the local activities and meteorological
conditions. Monthly variations were curved like a parabola at all station; the
minimum level was in the rainy season and the maximum level was in the winter.
The annual variations significantly increased at the Yupparaj Wittayalai School, the
National Housing Authority and the City Hall. However they decreased at
Dindaeng Housing Authority and the Public Service Centre.
Relationships between annual averaged NOx and NO2 were found as a
logarithm both roadside area and urban background area of all areas. For the
relationships of hourly averaged NOx and NO2 by the method of Darwent and
Middleton, a polynomial model was found as for the roadside areas in Bangkok and
regional parts of the country and a logarithm model was found for the urban
background areas in Bangkok. However, there was no such relationship for urban
background areas in regional areas. The study also found that P95-NO2 was around
3 times the annual mean NO2.