Air Quality Assessment of Cement Manufacturing Process: A Case Study in Khulna City

Abstract

Air pollution has deleterious impacts on human health and environment. Industrial sector has always led to increase the immense challenge of controlling this atmospheric pollution. Cement industry is one of the potential anthropogenic sources of air pollution and gradual substitution of traditional building patterns by modern high-rise ones has pushed up the use of cement in Bangladesh. It may cause an alteration on the air quality of Bangladesh in near future until any initiatives taken. Therefore, this study has made an attempt to determine the contribution level of a sampled cement manufacturing factory (CMF) on human health. With this consequence, this study has estimated the emission of air pollutant’s by emission factor method, characterized existed materials by different micro analysis such as XRF, particle size analysis SEM-EDS, XRD, and FTIR to correlate them with the health risk exposure. In addition it has also assessed occupational health risks at sampled CMF. The results of XRF analysis showed that the oxides such as CaO, SiO2, Al2O3, MgO, SO3, K2O, Na2O, and Fe2O3 are available in raw materials, products and by-products of CMF. SEM micrographs have evidently shown the existence of fine particles (<PM 0.5). The presence of heavy metals i.e. Ti and Mo are identified (Ti in clinker, gypsum and fly-ash, Mo in PCC, bag filter dust, clinker and slag) by EDS analysis. XRD analysis reveals the existence of carcinogenic substances i.e. α-quartz in sampled PCC, road dust, bag filter dust, fly ash and limestone. FTIR analysis also confirms the similar finding of XRD by bonding confirmation. The study reveals the sampled CMF at Labanchara, Khulna executes a grinding based cement production where raw materials including clinker are being imported. Consequently, the CMF emits less gaseous pollutants and however, it produces a significant amount of dust. The CMF generates dust of approximately 50.31 metric ton/year to the surroundings. It signifies 51 g of dust is being discharged from per metric ton cement production or 2.57 g of dust from 1 cement bag. The CMF has the total annual emission of 162 kg, 157 kg, 33 kg, 13 kg and 11 kg of CO, NOx, VOCs, SO2, and PM10 respectively for vehicular movement. The AQI of Labanchara CMF indicates moderate level of health concern. Annual number of premature deaths due to exposure to PM10 is found for all cause mortality as 0.145 (95% CI: 0.115-0.178) at Labanchara CMF. Annual number of premature deaths due to exposure to PM2.5 is found as 0.135 (95% CI: 0.055-0.194) and 0.009 (95% CI: 0.004-0.012) for cardio-pulmonary diseases and lung cancer respectively there. The DALYs for study area has found as 6 hours per year per worker at CMF due to the exposure of PM which indicates the importance of imposing emission estimation and reporting policy for cement industries in Bangladesh. The study concludes that the PCC is more hazardous than OPC regarding the health issue as it contains comparatively finer particles and carcinogenic substances such as crystalline silica originated from fly ash. Also the presence of very fine particles, heavy metals and crystalline silica making the cement dusts itself very hazardous substances. As a result it can cause harm on people upon inhalation staying within industry or in the vicinity of its surrounding. Even people working in or near construction site may be in alarming condition if no measure is taken when this cement product will be used for construction.