Analysis Of Sources Of VOCs In Suburb Of Nanjing And Their Impact On Ozone And Health

This study is based on the combination of pollutants such as VOCs,O3,and O3 precursors observed in the northern suburbs of Nanjing,and uses the emission sources identified by PMF and Unmix models to understand the composition and characteristics of VOCs.OBM was used to analyze the contribution of VOCs and their sources to O3 generation,and sensitivity experiments were combined with PMF results to evaluate the impact of O3 on each source.Health risk assessment of BTEX was conducted using the EPA human exposure assessment method and the impact of the source on health was assessed.In 2013,the average VOCs concentrations during the observation period in 2014 and 2015 were(30.16±35.68)×10-9,(36.47±33.44)x10-9,and(34.69±34.08)×10-9,respectively.The concentration of substances in the observation period is similar,and the concentration of alkanes is the highest.PMF identified sources of emissions from automotive exhaust,LPG,biogenic emissions,furniture manufacturing,chemical industry,chemical coatings,and chemical materials.The results obtained by PMF and Unmix show good agreement.The relationship between O3 and precursors was evaluated in OBM simulations.The northern suburbs of Nanjing are controlled by VOCs(positive RIR values).The olefins(1.20?1.79)and aromatic hydrocarbons(1.42?1.48)exhibited higher RIR values,and the RIR values reached the highest when the olefin emissions decreased by 80%.The three types of VOCs sources that have the largest contribution from automobile exhaust(1.01?1.11),LPG(0.74?0,82),and biogenic emissions(0.34?0.42);reducing these three types of emissions is the most effective strategy for reducing local O3 generation.HQ risk values are within safe range for all BTEX analysis periods.The R values in the northern suburbs of Nanjing showed the distribution pattern of winter>autumn>spring>summer;R exceeded the safety threshold at all analysis times,and there was a carcinogenic risk.From 2013 to 2015,the total HQ is within the safety range,and the non-carcinogenic risk to the human body is low,among which the HQ emissions from chemical plants are the highest.The highest benzene R values for chemical emission within three years of 1.53×10-5,1.54×10-5,and 1.64×10-5 all exceeded the safety threshold,causing cancer risk.