Assessment of airborne endotoxin in sandstorm dust and indoor environments using a novel passive sampling device in Al Zulfi city, Saudi Arabia – Establishing threshold exposure levels

Abstract

The impact of sandstorm dust events affects local air quality and public health. These issues are becoming of greater concern in Saudi Arabia. There is a significant lack of research on airborne endotoxin exposure and analysis in the Middle East countries and no coherent body of research exists focusing on sandstorm dust in worldwide. In this study, we used a novel design of an aluminum foil plate (AFP) electrostatic dust cloth (EDC) for the passive air sampling of sandstorm dust. A total of 38 sandstorm dust samples were collected during sandstorm episodes occurring between January and April 2020 in both indoor (7 days, n = 20) and outdoor environments (24 h, n = 18). After exposure, and following an extraction procedure, bacterial endotoxin levels were measured using the Limulus Amoebocyte Lysate (LAL) gel clot method. The study highlights that the airborne endotoxin level observed was between 10 and 200 EU/m 2 in both indoor and outdoor environments, during a sandstorm event. Agricultural activities and farmhouses observed higher airborne endotoxin levels. In general, increased endotoxin levels were related to the severity of the sandstorms. Given that the observed values were high as per existing guidelines for respiratory health, we recommend the setting an occupational airborne exposure limit for bacterial endotoxin. This is the first report and further studies across various sandstorm-hit regions will need to be undertaken, together with various sampling methods, in order to assess for seasonal and geographic trends.

Isolation of Microorgansims from the Air Conditioning System in Cars

“…Symptoms include persistent cold, watery eye, prolong muscle cramps and joint pain. The bacteria identified are ranged from cocci, diplococcic, gram negative and positive bacteria (table7).More organisms were reported to be attributed to the changes in weather condition with dry season having a lot of dust particle that could have contained microbial spores as they are blown into the air by the wind, these results were similar to the Study conducted by (Vijayakumar R et al, 2021, Sattar AS et al 2017, estimated the level of bacteria and fungi concentration prior and after using of the automobile air conditioning. Moreover, the qualitative analysis of bacterial and fungal aerosols found the car air cabins before the AC service used were 28 bacterial species from 10 genera and 31 fungal species belonging to 18 genera.…”