Mortality Burden due to Exposure to Outdoor Fine Particulate Matter in Hanoi, Vietnam: Health Impact Assessment.

Objective: This study reports the mortality burden due to PM2.5 exposure among adults (age >25) living in Hanoi in 2017. Methods: We applied a health impact assessment methodology with the global exposure mortality model and a PM2.5 map with 3 × 3 km resolution derived from multiple data sources. Results: The annual average PM2.5 concentration for each grid ranged from 22.1 to 37.2 µg/m³. The district average concentration values ranged from 26.9 to 37.2 µg/m³, which means that none of the 30 districts had annual average values below the Vietnam Ambient National Standard of 25 µg/m3. Using the Vietnam Ambient National Standard as the reference standard, we estimated that 2,696 deaths (95% CI: 2,225 to 3,158) per year were attributable to exposure to elevated PM2.5 concentrations in Hanoi. Using the Interim Target 4 value of 10 µg/m3 as the reference standard, the number of excess deaths attributable to elevated PM2.5 exposure was 4,760 (95% CI: 3,958-5,534). Conclusion: A significant proportion of deaths in Hanoi could be avoided by reducing air pollution concentrations to a level consistent with the Vietnam Ambient National Standard.

Development of a bacteriophage-based Method for Detection of Escherichia Coli O157:H7 in Fresh Vegetables.

In this study, a method using a recombinant phage for detection of E. coli O157:H7 in fresh vegetables was investigated. Four kinds of fresh vegetables, i.e. lettuce (Lactuca sativa), mustard greens (Brassica juncea), coriander (Coriandrum sativum), and soybean sprouts were selected since they are commonly used in meals in Vietnam. Firstly, a phage-based method was investigated for detection of E. coli O157:H7 in the four types of vegetables. To support the detection by suppressing growth of background bacteria in vegetables, selective antibiotics, i.e. novobiocin (N) and vancomycin (V) in combination with BHI medium were examined. Secondly, quality of the method was evaluated in terms of sensitivity, specificity, and rapidity. The method enabled the detection of E. coli O157:H7 inoculated at 103, 102, or 101 CFU/ 10 mL of sterile 0.8% NaCl containing 5 g of vegetable and in the presence of several Gram-positive and Gram-negative bacteria inoculated at 107 CFU/10 mL. The time for detection was approximately 16.5 hours for E. coli O157:H7 inoculated at 10 CFU/10 mL of sterile 0.8% NaCl containing 5 g of vegetable. The limit of detection was considered to be 2 CFU g-1 vegetable.