Air pollutant emissions from straw open burning: A case study in Tianjin

Straw open burning is a primary source of air pollution and difficult to forbid in China. To have a better understanding of the pollution status of straw open burning in Tianjin, an accurate pollutant emission inventory was established based on the county-level statistical data from 1996 to 2014 in Tianjin. Results showed that the emission of CO, VOCs, PM10, PM2.5, CH4, NOx, OC, SO2, NH3 and BC have decreased by 41.66%, 58.74%, 54.55%, 55.01%, 58.42%, 47.03%, 48.71%, 44.85%, 64.60%, 51.56% from 1996 to 2000, and then gradually increased by 44.05%, 53.48%, 59.43%, 59.49%, 51.24%, 55.05%, 53.09%, 22.73%, 56.25%, and 64.29% from 2000 to 2014, respectively. Spatially, counties of Wuqing, Baodi and Jixian were the largest contributors to the total emissions with the contribution of 25.98%, 22.69% and 18.87% respectively through the study period. The Monte Carlo simulation was also used to estimate the uncertainty and its confidence intervals of the pollutant emissions. The uncertainty of total pollutant emissions for each year is within 80.35%. This study provides more accurate estimation for the pollutant emissions from straw open burning and reliable guidance for the policy formulation to improve the air quality in Tianjin.