Emission factors and source profiles of volatile organic compounds from the automobile manufacturing industry

Controlling volatile organic compounds (VOCs) emitted from the automobile manufacturing industry requires establishing VOCs emission factors (EFs) and source profiles refinedly. In this study, 41 samples involved 32 VOCs discharge links were collected from three factories. The EFs and VOCs source profiles were estimated by the material balance method and weighted average method, respectively. The ozone formation potential (OFP) of the 110 VOCs species were calculated by the maximum incremental reactivity (MIR). According to estimations, the ranges of EFs were 0.23-1.66 kg VOCs/SUV car and 2.14-14.86 g VOCs/m2 painted area. EFs of six materials were firstly estimated, which are electrophoretic primer (152.31 ± 97.39 g VOCs/SUV car, 0.97 ± 0.38 g VOCs/m2 painted area), sealant (48.39 ± 26.20 g VOCs/SUV car, 0.46 ± 0.25 g VOCs/m2 painted area), floating coat (87.40 ± 75.63 g VOCs/SUV car, 0.86 ± 0.74 g VOCs/m2 painted area), colored paint (127.24 ± 168.24 g VOCs/SUV car, 1.25 ± 1.66 g VOCs/m2 painted area), varnish (205.46 ± 218.14 g VOCs/SUV car, 2.01 ± 2.15 g VOCs/m2 painted area), and cleaning solvent (328.54 ± 404.94 g VOCs/SUV car, 3.23 ± 3.98 g VOCs/m2 painted area). OVOCs (37.40-51.60 %) and aromatics (36.40-37.00 %) were the dominant components. n-Butyl acetate, 1,2,4-trimethylbenzene, undecane, n-hexanal, acetone, 1,2,3-trimethylbenzene, 1,3,5 -trimethylbenzene, m/p/o-xylene, 3-ethylbenzene, and 4-ethylbenzene were the major VOCs species, accounting for 68 % of total VOCs in the automobile manufacturing industry. Considering the OFP values of species, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, 1,2,3-trimethylbenzene, m/p-xylene, acetaldehyde, methyl ethyl ketone are the key active species that should be prioritized for control.

[Application and comparison of three occupational health risk assessment methods in an automobile manufacturing industry]

Objective: Three occupational health risk assessment methods were used to assess the occupational health risk of noise exposed posts in an automobile manufacturing enterprise. According to the results, the selection of risk assessment methods and risk management of such occupational noise enterprises were provided. Methods: Form April to November 2021, The occupational health field survey was carried out in an automobile manufacturing industry in Tianjin. The occupational health MES risk assessment method, occupational health risk index risk assessment method and Australian occupational hazard risk assessment method were used to evaluate the occupational health risk of noise-exposed posts in this enterprise, and the evaluation results of different methods were analyzed and compared. Results: The average value of L(Aeq, 8 h) in the four workshops of automobile manufacturing industry was 82.95 dB (A) , and the noise detection exceeding rate was 22.41% (26/116) . The LAeq, 8h and exceeding rate noise of welding workshop were higher than those of other workshops (χ(2)=23.56, 32.94, P<0.01) . The three occupational health risk assessment methods have the same risk assessment results for the four major workshops. The assembly and painting workshops are level 4 risk (possible risk) , and the stamping and welding workshops are level 3 risk (significant risk) . Conclusion: Occupational noise has certain potential hazards to workers in automobile manufacturing enterprises. Therefore, in the future work, corresponding organizational management measures should be taken to improve the working environment and reduce the actual exposure level of workers in order to protect the health of occupational workers.