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This technique for setting guideline values differs from that currently used by regulatory agencies throughout the world. Data for benzene were evaluated from epidemiological studies on human populations (29 studies). Exposure durations were evaluated in terms of Long Term Exposure (LTE) and Lifetime Exposure. All data was reported as Lowest Observed Adverse Effect Levels (LOAEL) and converted into exposure doses using Average Daily Dose (ADD) and Lifetime Average Daily Dose (LADD). These values were plotted as a Toxicant Sensitivity Distribution (TSD) which was the cumulative probability of LOAEL-ADD and LOAEL-LADD. From the TSD plots, linear regression equations gave correlation coefficients (R2) ranging from 0.69 to 0.97 indicating normal distributions. Guideline Values (GVs) for LTE (8hr/day) and Lifetime (24hr/70yrs) exposure to benzene were calculated using data from human epidemiological studies as 5% level of cumulative probability (CP) of LOAEL–ADD and LOAEL–LADD from the cumulative probability distributions (CPD). The derived guideline values from the human epidemiological studies were 92 μg/kg/day for LTE and 3.4 μg/kg/day for lifetime exposure. GV for LTE is appropriate for occupational exposure and GV derived for lifetime exposure appropriate for the general population. The guideline value for occupational exposure limit was below all the guideline values developed by regulatory agencies. But the general population guideline is within the range of values formulated by European Union, ATSDR, EPAQS, USEPA and OEHHA for air quality for the general population. This is an alternative method which eliminates the application of safety factors and other sources of errors in deriving guideline values for benzene. Image 1 • An alternative technique was used to set guideline values for exposure to benzene. • Benzene exposure data from human epidemiology studied were evaluated. • LOAEL used for plotting toxicant sensitivity distribution curves. • The derived values were 92 μg/kg/day for LTE and 3.4 μg/kg/day for lifetime exposure. • This method eliminates the use of safety factors and other sources of errors. An alternative technique of LOAEL based on toxicant sensitivity distribution curve was used to set guideline values for exposure to benzene as 92 μg/kg/day for long term exposure and 3.4 μg/kg/day for lifetime exposure. [ABSTRACT FROM AUTHOR]

Previous studies indicated that long-term exposure to high level of fine particulate matter (PM 2.5) was associated with elevated blood pressure (BP) and hypertension, but most of them were conducted in high-income countries with low PM 2.5 level. Therefore, we aimed to evaluate the adverse impacts of long-term exposure to PM 2.5 on BP and hypertension in China with high concentration. A total of 99,084 adults aged ≥18 years old were included from three cohorts among the project of Prediction for Atherosclerotic Cardiovascular Disease Risk in China. PM 2.5 concentrations during 2000–2015 at 1 × 1 km spatial resolution were evaluated using satellite-based spatiotemporal models. Generalized estimating equation was applied to assess the impact of three-year average PM 2.5 concentrations on BP level and hypertension. We also examined whether health status and lifestyles modified the effects of PM 2.5 on BP and hypertension. Generally, high concentration of PM 2.5 was associated with increased BP level and higher risk of hypertension. With each 10 μg/m3 increment in PM 2.5 concentration, systolic BP (SBP) and diastolic BP (DBP) increased by 1.67 [95% confidence interval (CI): 1.48, 1.86] mmHg and 0.45 (95% CI: 0.35, 0.56) mmHg, and the prevalence of hypertension increased by 29% [odds ratio (OR): 1.29, 95% CI: 1.26, 1.32]. In comparison with the first quartile of PM 2.5 concentration, SBP, DBP and prevalence of hypertension in the fourth quartile were increased by 8.26 (95% CI: 7.73, 8.80) mmHg, 2.85 (95% CI: 2.55, 3.15) mmHg, and 133% (OR: 2.33, 95% CI: 2.21, 2.47), respectively, in the fully adjusted model. However, the relationships of PM 2.5 with BP might be non-linear, as BP level started to decline when PM 2.5 exceeded 75 μg/m3. In conclusion, long-term PM 2.5 exposure could elevate BP level and prevalence of hypertension. People living in high-polluted areas should strengthen their awareness of prevention. [Display omitted] • Fine particulate matter exposure increases blood pressure and hypertension risk. • Effects of fine particulate matter on blood pressure differ from high-income areas. • Non-linear relationship of fine particulate matter with systolic blood pressure. [ABSTRACT FROM AUTHOR]