Abstract
Atmospheric fine particulate matters (PM2.5) were collected with an Envirotech Instrument (Model APM 550) at the roof of Khundkur Mukarram Hussain Science Building, University of Dhaka, Bangladesh between January and February, 2013. PM2.5 samples were collected on Quartz fiber filters during day and night time. Water soluble ions (sulfate, nitrate, phosphate, chloride, bromide, sodium, potassium and calcium) were analyzed with Ion Chromatography (Model 881, Metrohm Ltd., Switzerland) and Flame photometer (Model PFP7, Jenway, UK). Average PM2.5 mass was 136.1 μg·mDž during day time and 246.8 μg·mDž during night time with a total average of 191.4 μg·mDž. Nighttime PM2.5 concentration was about double compared than that of daytime presumable due to the low ambient temperatures with high emissions from heavy duty vehicles. The 24-hour average PM2.5 mass (average of day and night) was about eight times higher than WHO (25.0 μg·mDž) and about three times higher than DoE, Bangladesh (65.0 μg·mDž) limit values. The total average concentrations of sulfate, nitrate, phosphate, bromide, chloride, sodium, potassium and calcium were 5.30, 7.75, 0.62, 0.16, 1.19, 1.30, 8.11, and 3.09 μg·mDž, respectively. The concentrations of the water soluble ions were much higher during nighttime than daytime except nitrate, bromide and potassium. Excellent correlations were observed between sulfate and nitrate, sodium and chloride, bromide and phosphate indicating joint sources of origin. Potassium, sulfate, nitrate and calcium are the most dominant species in PM2.5. Water soluble ionic components in Dhaka contributed about 15% mass of the PM2.5. Ratio analysis showed that sodium and chloride were from mainly sea salt. Potassium has varieties of sources other than biomass burning. Sulfate and nitrate are mainly from fossil fuel origin. This is the first study of the day and night variation of the water soluble ionic species at the fine particulate matters (PM2.5) in Bangladesh.
Highlights
Atmospheric particulate matters have a significant impact on human health, climate change, visibility reduction and on the natural ecosystems [1]-[7]
Particulate matters with aerodynamic diameters less than 2.5 μm (PM2.5) have especially been found associated with increasing respiratory illness, carcinogens, asthma [1] [11] and in increasing number of premature deaths
The highest PM2.5 concentration was observed on January 27, 2013 (379.3 μg·m−3) and the lowest concentration was on January 28, 2013 (157.6 μg·m−3) for the day time
Summary
Atmospheric particulate matters have a significant impact on human health, climate change, visibility reduction and on the natural ecosystems [1]-[7]. Epidemiological studies have indicated a strong association between the elevated concentration of inhalable particles and increased mortality and morbidity [8] [9]. Fine particles have serious health impact as they can enter in the alveoli of the human respiratory system. Many epidemic studies have linked airborne concentrations of PM2.5 and PM10 with a variety of health problems, including the morbidity as well as mortality [10]. Particulate matters with aerodynamic diameters less than 2.5 μm (PM2.5) have especially been found associated with increasing respiratory illness, carcinogens, asthma [1] [11] and in increasing number of premature deaths. The high levels of PM2.5 have been associated with amenity problems such as visibility degradation associated with haze [12]
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