Assessment of bioaerosol particle characteristics at different hospital wards and operating theaters: A case study in Tehran

This study was aimed to investigate the types and number of bacterial and fungal bioaerosols in indoor air of hospitals according to the type of wards and operating theaters. Bacterial and fungal samples were collected using the passive sampling method of 1/1/1 scheme during a six months' period in the Khatam-Al-Anbia hospital, Tehran, Iran. A simple linear regression was used to determine the relationship between bioaerosol concentrations and the number of active beds. Bacterial bioaerosol concentrations were mainly higher than fungi in all sampling sites. A significant association was found between airborne fungal concentrations and the numbers of beds (R2 = 0.76, p < 0.05), but not observed for bacteria (R2 = 0.02, p < 0.05). Our findings provided an exposure database of airborne bacterial and fungal bioaerosol in hospital wards and operating theaters in Tehran. • Due to the importance of the exposure risk to bioaerosols for patients and medical personnel, we focused on identification of the density and diversity of bacterial and fungal bioaerosols in different wards and operating theaters. • Our results showed that the numbers of the beds have a significant effect on airborne fungal concentrations. • The results of this study can be used to set indoor air quality standards for hospital wards and operating theatres. Method name: Bacterial and fungal samples were collected using the passive sampling method of 1/1/1 scheme during a six months' period in the specialty and subspecialty the hospital from August 2015 to February 2016, Keywords: Hospital airborne bioaerosols, Indoor air, Fungal bioaerosol, Tehra

Relationship between ambient black carbon and daily mortality in Tehran, Iran: a distributed lag nonlinear time series analysis

Purpose The aim of the present study was to investigate the effect of short-term exposure to ambient black carbon (BC) on daily cause-specific mortality, including mortality due to respiratory, cardiovascular, ischemic heart and cerebrovascular diseases in Tehran, Iran. Materials and methods Daily non-accidental death counts, meteorological data and hourly concentrations of air pollutants from 2014 to 2017 were collected in Tehran. A distributed lag non-linear model was used to assess the association between exposure to BC and daily mortality. Results The mean daily BC concentration during the study period was 3.96 ± 1.19 µg/m3. The results indicated that BC was significantly associated with cardiovascular, ischemic heart disease, and cerebrovascular mortality, but not with respiratory mortality. In first model, each 10 µg/m3 increase in at lag 3, lag 4 and lag 5 were associated with cardiovascular mortality in 16–65 year age group with the relative risks (RRs) of 1.17 (95 % CI: 1.02–1.33), 1.17 (95 % CI: 1.04–1.31) and 1.12 (95 % CI: 1.02–1.24), respectively. The highest mortality rate per 10 µg/m3 increase in exposure was found for ischemic heart diseases with RR of 3.98 (95 % CI: 1.04–1.81, lag 01) for 16–65 age group. Cerebrovascular mortality was associated with 10 µg/m3 increases in non-cumulative exposure with RR of 1.17 (95 % 1.009–1.35, lag 5) in the age group ≥ 65 years. In the second model for a 10 µg/m3 increase in BC, cardiovascular mortality at specific lag days (5 and 6 days) in the age group ≤ 16 years were associated with RR of 1.34 (95 % CI 1.08–1.66) and 1.35(95 % CI 1.02–1.77), respectively. Conclusions This study in Tehran found significant effects of BC exposure on daily mortality for cardiovascular, ischemic heart disease, cerebrovascular disease.This study was funded by Shahid Beheshti University of Medical Sciences, Tehran, Iran (Grant number: 19307). The authors thank from Ministry of Health and Medical Education & Tehran Air Quality Company (TAQC) for providing data. The authors thank from Ministry of Health and Medical Education, for providing mortality data.Peer reviewe