Temporal and Spatial Variations in Ambient Air Quality during 1996-2009 in Bangkok, Thailand

Abstract

The severe air pollution in Bangkok (BKK) is an important issue in Thailand. The Bangkok air quality and meteorological data used in this study were collected by the Pollution Control Department of the Ministry of Natural Resources and Environment, Thailand, during 1996-2009. Measurements of hourly air quality and meteorological data were derived from 10 residential and seven roadside sites. Pearson's chi-square cross tabulation statistics show that the 24-hour mean PM 10 concentrations at both roadside and residential sites were to be significantly higher than the Thai National ambient air quality standards (NAAQS) and World Health Organization (WHO) guidelines. The daily 1-hour maximum O 3 (O 3-1hr ) concentration was higher than the Thai NAAQS at both sites. However, the concentrations of 8-hour time-weighting average of CO (CO 8hr ) were lower than the Thai NAAQS at both sites. The 24-hour average SO 2 concentration and the daily 1-hour mean concentration of NO 2 were higher than the WHO guidelines, but complied with the Thai NAAQS at both sites. A stepwise multiple linear regression model was used to analyze the significant factors affecting PM 10 , CO 8hr , O 3-1hr , NO 2 , and SO 2 levels at both sites, and the results showed a decreased association with meteorological parameters and an increased association with the area studied and seasons. In contrast, O 3-1hr levels exhibited a decreased association with the area studied. This study found that traffic emissions are the major factor causing the spatial variation in air pollutants in BKK, Thailand, while the meteorological parameters might be the main factors that affect the temporal variations. Our findings show the heterogeneously spatiotemporal characteristics of air pollution in BKK, and can be used to help mitigate this problem.

Assessment of Air Pollution in Bangkok Metropolitan Region, Thailand

“…The hourly maximum concentration of SO2 ranged from 13-163 ppb. 15 Even though the hourly maximum concentrations of the other gaseous species were generally lower than their standards, the hourly maximum concentrations of O3 were greater than its standard. The average concentrations of O3 were ~22.0±19.8 ppb, 17.9±16.9 ppb and 13.3±12.7 ppb over BKK suburb sites, BKK sites and roadside sites, respectively.…”

“…The double-peak pattern of SO2 over roadside sites indicates that SO2 is influenced by emission primarily from vehicle exhaust using high sulfur content fuel, especially high sulfur diesel. The study of ambient air SO2 patterns 15 in European cities by Henschel et al (2013) showed that diurnal patterns of SO2 had a double-peak pattern which the morning peaks more likely related to emission during rush hour, evening peaks were possibly caused by traffic and meteorology-collapse of the planetary boundary layer. It is noteworthy that BKK has a large diesel engine fleet (an estimated 25 % of registered vehicles) (DLT, 2015a).…”

“…The largest number of O3 exceedances ([O3]hourly > 100 ppb) occurred in the year 2000 with 174 hours of exceedances (Oanh and Zhang, 2004). Furthermore,5 BMR is considered as a region with the worst air quality in Thailand (Watcharavitoon et al, 2013). The transportation and industrial sectors are considered to be the major sources of air pollutants in BKK (Watcharavitoon et al, 2013).…”

“…Furthermore,5 BMR is considered as a region with the worst air quality in Thailand (Watcharavitoon et al, 2013). The transportation and industrial sectors are considered to be the major sources of air pollutants in BKK (Watcharavitoon et al, 2013). The number of vehicles in Thailand has increased since 1989.…”

“…According to the database of the Department of Industrial Work (DIW), Thailand, the number of registered manufacturing plants in Nakhon Pathom, Pathum Thani, Nonthaburi, Samut Prakan, and Samut Sakhon are 3,282 (DIW, 2016), 3,756 (DIW, 2016a, 1,981 (DIW, 2016b), 7,357 (DIW, 2016c) and 6,035 (DIW, 2016d. A variety of manufacturing facilities are located on the outskirts of BKK, including, metal, auto parts, paper, plastic, food, chemical 15 manufacturing and power plants.…”