Exposure and health risk assessment of volatile organic compounds among drivers and passengers in long-distance buses.

Exposure to volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene, xylene, and formaldehyde from long-distance buses has been reported to adversely affect human health. This study investigates the concentrations of these five VOCs and evaluates their health risks to drivers and passengers on board. Ten trips from Taipei to Taichung were performed during the warm and cold seasons of 2021-2022. Two locations inside the bus were established to collect air samples by a 6-liter canister for drivers and passengers. Exposure concentrations of benzene, toluene, ethylbenzene, and xylene were analyzed via gas chromatography with a flame ionization detector and the formaldehyde concentration was monitored using a formaldehyde meter. Subsequently, a Monte Carlo simulation was conducted to evaluate the carcinogenic and non-carcinogenic risks of the five VOCs. Formaldehyde emerged as the highest detected compound (9.06 ± 3.77 µg/m3), followed by toluene (median: 6.11 µg/m3; range: 3.86-14.69 µg/m3). In particular, formaldehyde was identified to have the significantly higher concentration during non-rush hours (10.67 ± 3.21 µg/m3) than that during rush hours (7.45 ± 3.41 µg/m3) and during the warm season (10.71 ± 2.97 µg/m3) compared with that during the cold season (7.41 ± 4.26 µg/m3). Regarding non-carcinogenic risks to drivers and passengers, the chronic hazard indices for these five VOCs were under 1 to indicate an acceptable risk. In terms of carcinogenic risk, the median risks of benzene and formaldehyde for drivers were 2.88 × 10-6 (95% confidence interval [CI]: 2.11 × 10-6 - 5.13 × 10-6) and 1.91 × 10-6 (95% CI: 4.54 × 10-7 - 3.44 × 10-6), respectively. In contrast, the median carcinogenic risks of benzene and formaldehyde for passengers were less than 1 × 10-6 to present an acceptable risk. This study suggests that benzene and formaldehyde may present carcinogenic risks for drivers. Moreover, the non-carcinogenic risk for drivers and passengers is deemed acceptable. We recommended that the ventilation frequency be increased to mitigate exposure to VOCs in long-distance buses.

Exposure and health risk assessment of indoor volatile organic compounds in a medical university.

Many volatile organic compounds (VOCs) are used for experiments at universities, and most of them contain benzene, toluene, ethylbenzene, xylene, and an extraction solvent of dichloromethane. This study aimed to investigate the indoor concentrations of these five compounds in different locations on campus and to evaluate possible health risks for faculty members and students in a medical university. We selected 10 locations as sampling sites to conduct 4-h monitoring sessions on weekdays each season during 2019-2020. We used a 6-liter canister to collect air samples and analyzed these five VOCs via gas chromatography with a flame ionization detector. Monte Carlo simulation was performed to evaluate the carcinogenic and noncarcinogenic risks of these five VOCs. We found that dichloromethane was the most highly detected compound (median: 621.07 µg/m3; range: 44.01-8523.91 µg/m3), and the Department of Medicine had the highest concentration of the total of these VOCs among all of the locations (median: 5595.29 µg/m3; range: 1565.67-7398.66 µg/m3). The median carcinogenic risks of dichloromethane and benzene were 6.36 × 10-5 (95% confidence interval [CI]: 6.83 × 10-6-7.37 × 10-4) and 5.47 × 10-6 (95% CI: 4.03 × 10-7-2.42 × 10-5), respectively, for faculty members, and the lower risks of 3.14 × 10-5 (95% CI: 3.39 × 10-6-3.64 × 10-4) and 2.69 × 10-6 (95% CI: 1.97 × 10-7-1.19 × 10-5) were estimated for the students. The chronic noncarcinogenic risks of four VOCs were less than one, except for dichloromethane with a median hazard index of 1.92 (95% CI: 2.11 × 10-1-2.22 × 101). This study observed the spatial variation in the concentrations of the total of five VOCs and dichloromethane. The carcinogenic risks were classified as being at the possible level, and the noncarcinogenic risk of dichloromethane was greater than the acceptable level. Increasing local exhaust ventilation during the experiment and reducing the using amount of dichloromethane are recommended actions to reduce VOCs exposures in the medical university.

Low bone mineral density in COPD patients with osteoporosis is related to low daily physical activity and high COPD assessment test scores.

COPD patients have an increased prevalence of osteoporosis (OP) compared with healthy people. Physical inactivity in COPD patients is a crucial risk factor for OP; the COPD assessment test (CAT) is the newest assessment tool for the health status and daily activities of COPD patients. This study investigated the relationship among daily physical activity (DPA), CAT scores, and bone mineral density (BMD) in COPD patients with or without OP. This study included 30 participants. Ambulatory DPA was measured using actigraphy and oxygen saturation by using a pulse oximeter. BMD was measured using dual-energy X-ray absorptiometry. OP was defined as a T-score (standard deviations from a young, sex-specific reference mean BMD) less than or equal to -2.5 SD for the lumbar spine, total hip, and femoral neck. We quantified oxygen desaturation during DPA by using a desaturation index and recorded all DPA, except during sleep. COPD patients with OP had lower DPA and higher CAT scores than those of patients without OP. DPA was significantly positively correlated with (lumbar spine, total hip, and femoral neck) BMD (r=0.399, 0.602, 0.438, respectively, all P<0.05) and T-score (r=0.471, 0.531, 0.459, respectively, all P<0.05), whereas CAT scores were significantly negatively correlated with (total hip and femoral neck) BMD (r=-0.412, -0.552, respectively, P<0.05) and (lumbar spine, total hip, and femoral neck) T-score (r=-0.389, -0.429, -0.543, respectively, P<0.05). Low femoral neck BMD in COPD patients was related to high CAT scores. Our results show no significant difference in desaturation index, low SpO2, and inflammatory markers (IL-6, TNF-α, IL-8/CXCL8, CRP, and 8-isoprostane) between the two groups. Chest physicians should be aware that COPD patients with OP have low DPA and high CAT scores.