Paper Title
Seasonal Patterns and Trends of Air Pollutant Concentrations in Chiang Mai and Lampang Provinces (Thailand): 2004-2018

The economy growth in Chiang Mai and Lampang provinces of Thailand resulted in the increases in air pollution levels, eventually negativelyaffect the environmental and public health. A major source of those air pollutants is the biomass burningduring December to April of every year.The objective of this study was to investigate the seasonal patterns and trends of air pollutants in Chiang Mai and Lampang provinces, Thailand from 2004 to 2018.The hourly air pollutant concentration was retrieved from monitoring stations ofthe Pollution Control Department of Thailand (PCD). The measured air pollutantsincluded carbon monoxide (CO), nitrogen oxide (NOX), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), particulate matter 10 (PM10) and fine particulate matter (PM2.5). Cubic spline function was used to identify the seasonal patterns and trends.This study found that the air pollutant concentrations in urban area (Chiang Mai) were different from rural area (Lampang). There were obvious seasonal patterns of O3, NO2, NOX, PM10 and PM2.5. Their concentration raised during the end of week in December to April except concentration of SO2in both provinces and CO in Lampang with no observable seasonal patterns. Overall, the trends of all pollutant concentration were in a moderate decline over the 15 year period. The findings were discussed with a perspective to provide policy recommendations, better management and control for air quality improvements in Chiang Mai andLampang provinces of Thailand. The government therefore should issue some particular actions in order to reduce or stop the biomass burning in this period. Keywords - Seasonal Patterns, Trends, Air Pollutant Concentrations, Chiang Mai and Lampang Provinces