Source Identification of Chittagong Aerosol by Receptor Modeling

Abstract

Samples of fine and coarse airborne particulate matter (PM) were collected between February and July 2007 at the Continuous Air Monitoring Station (CAMS) in Chittagong, the second largest city in Bangladesh. Samples were collected using a dichotomous sampler in two fractions of <2.5 mm (fine) and 2.5 to 10 mm (coarse). Samples were analyzed for elemental concentrations by proton induced X-ray emission (PIXE), hydrogen by proton elastic scattering analysis (PESA), and black carbon by reflectometry. Elemental data sets together with black carbon were analyzed by positive matrix factorization to identify the possible sources of mass for the coarse and fine PM fractions. Best solutions were found to be six and seven factors for elemental compositions for coarse and fine fractions at the CAMS at Chittagong, respectively. Sources were identified as biomass burning=brick kiln, soil dust, road dust, Zn source (including two-stroke motorcycles), motor vehicle, CNG vehicle, and sea salt. The PMF results show that about 35.5% of PM 2.5 mass at this site comes from biomass burning. The second largest contribution of fine PM comes from motor vehicle including CNG vehicles. The third one is a Zn source that includes emissions from two-stroke vehicles and galvanizing factories with vehicles, probably the larger contributor of the two source types. In case of coarse PM, about 40% of PM 2.5-10 mass comes from soil dust including road dust.

Trend of ambient air quality in Chittagong City

“…A high concentration of air pollutants such as black carbon in Dhaka City has been reported (Salam et al, 2003). Sources identification for air pollution has been done by (Begum et al, 2009 Table I.…”

Identification and Apportionment of Sources from Air Particulate Matter at Urban Environments in Bangladesh

“…From Table 8 (Chittagong), it can be seen that the fine PM mass contribution from brick kilns has increased from the 2006-2007 period, but the BC contributions have decreased [32]. The second largest contribution comes from sea salt/Zn source.…”

“…The location of the CAMS-3 is at the Chittagong Television Station Campus at Khulshi, which is on a hilltop about 2.5km northwest of the Chittagong downtown area and about 100 meters above the surrounding area. The location is not strongly affected by nearby air pollution sources, and it is considered representative of the air pollutant concentrations of the city [11]. The major sources were biomass burning/brick kilns, soil dust, road dust, Zn source (including two-stroke motorcycles), motor vehicles, CNG (Compressed natural gas) vehicle, and sea salt in the Chittagong aerosol [11].…”

“…The location is not strongly affected by nearby air pollution sources, and it is considered representative of the air pollutant concentrations of the city [11]. The major sources were biomass burning/brick kilns, soil dust, road dust, Zn source (including two-stroke motorcycles), motor vehicles, CNG (Compressed natural gas) vehicle, and sea salt in the Chittagong aerosol [11]. The PM samples were collected between September 2010 and July 2012 depending on the cities and the sampling time was from 10 am to 10 am (24h) ( Table 1).…”

Trajectory-Based Models and Remote Sensing for Biomass Burning Assessment in Bangladesh

“…Multiple source apportionment studies using positive matrix factorization (PMF) have also been conducted (e.g., Begum et al, 2004Begum et al, , 2005Begum et al, , 2009Begum et al, , 2010. These results suggested that the typical haze aerosol comes from domestic wood, dung and bagasse burning, forest fires, and combustion connected to agriculture activities and brick kiln making, i.e., biomass burning in general, but also from traffic, power plants, industry emissions, soil and road dust, and also sea salt (Begum et al, 2014).…”