Purpose Unidentified dynamics for the causative agent of COVID-19, SARS-Cov-2, led to the critical public health issue. Suspicion for the airborne potential of SARS-Cov-2 is an important problem for its transmission and relevant epidemics. This research investigated hospital indoor air quality to SARS-Cov-2 occurrence and determination its air born potential. Methods The site study was a referral hospital with 630 beds for admitting of COVID-19 patients. Air sampling was done (n = 31) on selected wards including Emergency 1, Emergency 2, bedridden (4-B, 10-D), ICU 2, ICU 3, CT-SCAN, and laundry. The average temperature and relative humidities were 22 ± 1°C and 43 percent respectively. All glass impinger used for sampling in which the sampling pumps capacities were 5 and 40 L.min − 1. Sampling duration time was 20 and 15 minutes and 100 to 1000 L of air were gathered. All parts of the sampling equipment were completely disinfected by hot water, ethanol (70%), chlorine solution (1000 ppm), hot water (70°C for 1 min) and washed with distilled water. The transmitting media (7 ml) was injected into impinger and residual of this media (2 ml) was sent to the virology laboratory within 2 hours and preserved on refrigerator < 4°C. Analysis of samples was performed by RT-PCR and repeated for accuracy control. Results All of the samples were negative for SARS-Cov-2 occurrence. These results showed that SARS-Cov-2 had not airborne potential in this hospital. Conclusions Although SARS-Cov-2 similar to the SARS virus but, SARS-Cov-2 is not an airborne virus.

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The impact of the total organic carbon (TOC), chlorine dosage, water temperature, reaction time, pH, and seasonal variation on the formation of haloacetic acids (HAAs) in the Karoon River in Iran was studied. The results showed that dichloroacetic acid and trichloroacetic acid were the most detected HAA5. The HAA5 formation potential (HAA5FP) levels in the Karoon River water in spring time, when the water TOC content exceeded 4 mg/L, were 1.38 times higher than during the winter season, when the water TOC content was below 3.5 mg/L. There was not a strong correlation between the HAA5FP and the residence time for the Karoon River water. For the range of the water temperatures studied, there was little variation in the HAA5FP in cold water, but in warmer water, the values of the HAA5FP varied quickly.

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The aim of this study is to evaluate central composite design (CCD) and the Taguchi technique in the adsorption process. Contact time, initial concentration, and pH were selected as the variables, and the removal efficiency of Pb was chosen for the designated response. In addition, face-centered CCD and the L orthogonal array were used for the experimental design. The result indicated that, at optimum conditions, the removal efficiency of Pb was 80%. However, the value of R was greater than 0.95 for both the CCD and Taguchi techniques, which revealed that both techniques were suitable and in conformity with each other. Moreover, the results of analysis of variance and Prob > F < 0.05 showed the appropriate fit of the designated model with the experimental results. The probability of classifying the contributing variables by giving a percentage of the response quantity (Pb removal) made the Taguchi model an appropriate method for examining the effectiveness of different factors. pH was evaluated as the best input factor as it contributed 66.2% of Pb removal. The Taguchi technique was additionally confirmed by three-dimensional contour plots of CCD. Consequently, the Taguchi method with nine experimental runs and easy interaction plots is an appropriate substitute for CCD for several chemical engineering functions.