[Source Analysis and Environmental Health Risk Assessment of VOCs in Furniture Manufacturing].

Regarding furniture manufacturing, scholars have only studied the sources of VOCs in the spraying process, yet the main concern is the release of VOCs after the completion of the manufacturing process and its impact on indoor air quality. Therefore, in this study, the sources of VOCs for the entire process of furniture manufacturing were explored and probabilistic risk models were improved. Then, the carcinogenicity and non-carcinogenic health risks to workers at nine workstations in a furniture factory were evaluated via a Monte Carlo simulation method, and the sensitivity of each exposure parameter was analyzed. The results are as follows. The various types of paints, diluents, and curing agents used in the process of spraying primer paint and spraying surface paint release VOCs, such as benzene, toluene, xylene, styrene, butanone, cyclohexanone, butyl acetate, and ethyl acetate. The glue used in the leather pasting process, the glue process, and the viscose process generates VOCs, such as dichloromethane and ethyl acetate, and the paint remover used in the cleaning process emits dichloromethane. The carcinogenic risk at each station was more than 10-6. For benzene exposure, the probability of exceeding 10-6 was greater than 95% for all stations, excluding SWB, SWP, and CWP. The carcinogenicrisk of workers exposed to benzene was the highest at SWS, at 3.07×10-6±1.73×10-6, and the carcinogenicrisk of workers exposed to dichloromethane was the greatest at SWL, with a value of 5.14×10-6±2.70×10-6. The only non-carcinogenicrisk greater than 1 was to SWS workers. The parameters that had the greatest impact on the carcinogenic risk assessment were exposure day (ED), concentration (C), exposure time (ET), and exposure frequency (EF). In the non-carcinogenic risk assessment, the most influential variables were ED, ET, and EF. In addition, concentration also had a significant impact on the evaluation results.

[Health Risk Assessment of Volatile Organic Compounds for Different Commuting Modes].

In order to overcome the shortcomings of a single commuting mode, eight VOCs including benzene, toluene, xylene, ethylbenzene, styrene, formaldehyde, acetaldehyde, and acrolein were studied in five commuting modes in Guangzhou. Applying the Monte Carlo simulation method, we assessed the health risk of these VOCs in five commuting modes, cars, air-conditioned buses, non-air-conditioned buses, subways, and bicycles, and analyzed the sensitivity of each exposure parameter. We used Crystal Ball 11.1 with 10000 iterations of independent runs and 95% confidence interval. The results show that the commuters of air-conditioned buses and cars are subjected to a higher cancer risk, following the t-distribution and lognormal distribution with 1.65×10-5±5.74×10-9 and 5.01×10-6±3.56×10-11, with the probability of exceeding 10-6 of 97% and 74.85%, respectively. The cancer risks of bicycles, non-air-conditioned buses, and subways are smaller, but their averages are higher than 10-6. The commuters of cars and air-conditioned buses were subjected to a larger non-cancer risk, following the lognormal distribution of 2.51±2.74 and 1.20±1.36; the contributions of acrolein are above 80%. The non-cancer risk of bicycles is the smallest and will not be a threat to human health. Sensitivity analysis shows that the sensitivities of ET, CA, ED, IR, and EF are larger, with the values of 55.5%, 32%, 10.5%, 1.1%, 0.2%, respectively, and BW has negative sensitivity.

[Cancer Risk of Human Intake of PAH-Contaminated Particles Based on Hand-to-Mouth Activities].

The health risk of residents exposed to PAH-contaminated outdoor soil and indoor dust particles via hand-to-mouth transfer was estimated by developing probabilistic risk models. The cancer risk was assessed by applying the Monte Carlo method. The results showed that toddlers, children, and teens were at greatest risk of exposure, followed by infants, adults, and seniors. The probability of exceeding the acceptable level 10-6 was 2% for infants, 5% for toddlers and teens (none of the values were larger than the upper limit 10-4), 15% for children (0.1% of the values were larger than 10-4); and 1% and 0.1% for adults and seniors, respectively. Indoor dust posed a more serious threat than outdoor soil, which accounted for 91% of the total risk; indoor hard surfaces were the main sources of indoor dust with a contribution of 65%. The most influential variables were the frequency of hand-to-mouth events (FQ), benzo[a]pyrene from indoor dust (PEFj), dust surface load on horizontal soft surfaces (DSLSS) and hard surfaces (DSLHS), and saliva extraction factor (SE).

[Environmental Health Risk Assessment of Contaminated Soil Based on Monte Carlo Method: A Case of PAHs].

In order to obtain more reasonable health risk values and get the most significant factors, probabilistic risk models based on Monte Carlo simulation were applied, the health risk level of 16 PAHs in soil was evaluated for a residential area in Shanghai, China. And, sensitivity analysis was conducted for each parameter. The results showed that, the health risks caused by PAHs followed lognormal distribution with 3.43×10-5±2.63×10-5 for carcinogenic risk, which was between 8.10×10-7 and 2.39×10-4 and the probabilities exceeding 10-6, 10-5 and 10-4 were 95%, 75% and less than 5%. And the value was 4.74×10-2±3.42×10-2 for hazard quotient, which was between 1.38×10-3 and 2.85×10-1 and less than 1, so could be regarded negligible. As for total carcinogenic risk (TCR), the most influential PAHs were BaP, DBA and BaA, and their contribution rates were 60.41%, 26.84% and 6.56%, respectively. Among the three exposure pathways, the risk was mainly caused by oral intake with the contribution rate of 73.22%, followed by dermal contact with 26.51%. The most influential parameters were:intake amount of soil per day, exposure duration and exposed skin area with the sensitivity values of 58.35%, 50.21% and 20.51%, respectively. And body weight had a negative sensitivity with -11.66%. When it came to total hazard quotient (THQ), Pyr, FL and PA accounted for the most with 36.56%, 33.18% and 13.18%, respectively. And the oral intake and dermal contact were also primary exposure pathways with 72.21% and 26.36%. The most significant parameters were the same with TCR with the sensitivity values of 63.52%, 53.18%, 24.39% and -13.98%, respectively.