Quantification of residential heating emissions in Istanbul via CMAQ air quality model

Istanbul is the most populated city of Turkey as well as Europe. The population is over than 14 million. The city is economical center of the country. Labour and social opportunities makes the city attractive to live and this situation causes inevitable increasing on urbanization of the province. According to authorities, it is expected that the population will be over 16 million in 2030. Due to high population, house holding is also increasing. Distribution of buildings is expending over the city. Residential heating is the main requirement of the people in cold, winter season. By the high population and urbanization, residential heating emissions significantly affects air pollution over the city. Results of many epidemiological studies proves that air pollution causes negative impact on cardiovascular and respiratory system, serious diseases such as cancer and hearth attack. Especially for sensitive people such as elders, children, babies or pregnant the effects may be higher and vitally important. This study aims to examine residential heating impact over Istanbul city by atmospheric modelling. For this purpose WRF (Weather Research and Forecasting) meteorology model and CMAQ (Community Multiscale Air Quality) chemistry and transport model was applied. The first step was preparing emission inventory as input of the model. More complete and current emission inventory provides more trustable outputs. Residential heating emissions are generated with activity data and emission factor. The calculated emissions are also compared with TNO and EMEP emissions. Another purpose of this study was developing region specific emission factors of residential heating for Istanbul. The main fuels which are commonly used in the city are determined and combustion system is analysed. Residential heating is commonly supplied from natural gas and solid fuels such as coals and wood. The coals are classified as domestic and import coal. The fuels were burned in conventional stoves that is commonly used individual combustion system in Istanbul and pollutant concentrations are measured. The measurements for solid fuels were continuous and the concentration values of each pollutants are reported minutely. For natural gas, individual combustion system was combi and concentrations were measured instantaneously. Combustion systems, burning efficiency and calorific values of the fuels are essential for burning regime and pollutant concentrations. Moreover, fuel consumption per unit time is a critical parameter for emission factor calculation. By considering all these parameters and concentrations emission factors are calculated for each fuels and pollutants. The main pollutants of this source are SOx, NOx, CO, PM10. Moreover, uncertainties of region specific emission factors that are calculated with continuous measurements are evaluated for solid fuels. Statistical methods are used in order to quantify the factors. Both parametric and non-parametric bootstrapping techniques applied and many distribution fitting models and related diagnostics were applied in the study. The emissions via using calculated region specific emission factors and WRF meteorological model outputs were used as input of CMAQ. The study episode was three months that is from December 1, 2009 to February 30, 2010. As reference case CMAQ model is applied with TNO inventory and then the model is run for the same episode with new emission inventory that is updated with calculated residential emissions. The difference of concentrations between two model outputs provide to understand contribution of the revised residential emissions over the city. The days and hours that have maximum concentration differences are determined as giving the highest response to the new inventory.