Determinants of carbon load in airway macrophages in pregnant women.

The airway macrophages carbon loading (AMCL) has been suggested to be a biomarker of the long-term exposure to air pollution; however, to date no study has characterized AMCL for the pregnancy period. Therefore, this study aimed to assess the determinants of AMCL during pregnancy in Iran, a middle-income country. This study was based on a sample of 234 pregnant women with term and normal vaginal delivery who were residing in Sabzevar, Iran (2019). We characterized 35 potential determinants of personal exposure to air pollution for each participant, including six personal, nine indoor, and 20 home-outdoor factors. We applied Deletion/Substitution/Addition algorithm to identify the most relevant determinants that could predict AMCL levels. The median (IQR) of AMCL level was 0.12 (0.30) µm2 with a successful sputum induction in 82.9% (194) of participants. Ambient residential PM2.5 levels were positively associated with higher AMCL levels. On the other hand, increased residential distance to the traffic lights, squares and ring-roads, the duration of opening window per day, and opening window during cooking were inversely associated with AMCL levels. Our findings provide novel insights on the different personal, indoor, and outdoor determinants of personal exposure to air pollution during pregnancy in a middle-income country.

Effect of photocatalytic pretreatment on the biodegradation of n-hexane vapours in a biofilter.

Hydrophobic volatile organic compounds (VOCs) such as n-hexane are not completely biodegradable by a single biofilter. So, in the present study, a photoreactor system packed with scoria granules coated with TiO2, as a pretreatment unit, was used for increasing the removal efficiency of n-hexane by a biofilter during an operation period of 191 days. The inlet and outlet concentration of n-hexane was analyzed with a gas chromatography coupled with a flame ionization detector (GC/FID). The results indicated that the removal efficiency of the single biofilter with input concentrations of 0.18 - 1 g/m3 at empty bed residence times (EBRTs) of 30, 60, and 120 s was 10.06%, 21.45%, and 46.8%, respectively. When the photoreactor was used as a pretreatment system, the removal efficiency of the combined system in corresponding EBRTs was improved to 39.79%, 63.08%, and 92.60%, respectively. The results proved that the combined system provided higher removal efficiencies than the single biofilter. Thus, the application of the photoreactor as a pretreatment step was much effective in increasing the removal efficiency of n-hexane from the polluted air by the biofilter.

Concentrations and mortality due to short- and long-term exposure to PM2.5 in a megacity of Iran (2014-2019).

The present study aimed to survey the spatial and temporal trends of ambient concentration of PM2.5 and to estimate mortality attributed to short- and long-term exposure to PM2.5 in Isfahan from March 2014 to March 2019 using the AirQ+ software. The hourly concentrations of PM2.5 were obtained from the Isfahan Department of Environment and Isfahan Air Quality Monitoring Center. Then, the 24-h mean concentration of PM2.5 for each station was calculated using the Excel software. According to the results, the annual mean concentration of PM2.5 in 2014-2019 was 29.9-50.9 µg/m3, approximately 3-5 times higher than the WHO guideline (10 µg/m3). The data showed that people of Isfahan in almost 58% to 96% of the days of a year were exposed to PM2.5 higher than the WHO daily guideline. The concentrations of PM2.5 in cold months such as October, November, December and January were higher than those in the other months. The zoning of the annual concentrations of PM2.5 in urban areas showed that the highest PM2.5 concentrations were related to the northern, northwestern, southern and central areas of the city. On average, from 2014 to 2019, the number of deaths due to natural mortality, lung cancer (LC), chronic obstructive pulmonary disease (COPD), ischemic heart disease (IHD) and stroke associated with ambient PM2.5 were 948, 16, 18, 281 and 60, respectively. The present study estimated that on average, 14.29% of the total mortality, 17.2% of lung cancer (LC), 15.54% of chronic obstructive pulmonary disease (COPD), 17.12% of ischemic heart disease (IHD) and 14.94% of stroke mortalities were related to long-term exposure to ambient PM2.5. So provincial managers and politicians must adopt appropriate strategies to control air pollution and reduce the attributable health effects and economic losses.

Environmental and behavioral determinants affecting the association of airway macrophages carbon load with distance to major roads and traffic density.

Biomarkers are promising indicators to evaluate human exposure to air pollutants and to predict the health outcomes. Area of Airway macrophages that is occupied by Black Carbon could be used as a biomarker of personal long term exposure to traffic related air pollution. Association of airway macrophages carbon load with weighted average distance and environmental and subject-specific behavior are considered in this study. Sputum samples were taken from 160 healthy adult women and airway macrophages carbon load (AMCL) were determined in 93 subjects, which represent a success rate of 62% in sputum induction. Nearest distance of the subjects to major roads and average weighted distance were calculated for each subject. A questionnaire was field according to general and behavioral characteristics of the participants. There was not any significant difference (P-value >0.05) between induced and non-induced subjects. Subjects with indoor kitchen without separation wall, passive smokers and those with longer presence time in high traffic streets showed higher carbon area. Weighted average distance had a better association (ß = -0.186, 95%CI: -0.139, -0.230, P-value = 0.00) with AMCL than nearest distance to major roads (ß = -0.155, 95%CI: -0.109, -0.201, P-value = 0.19). Association of Weighted average distance with AMCL was interrupted in subjects with a garage connected to house environment, those with IK kitchen, those with a hood above the stove and passive smokers. The findings indicated that more generation and distribution of indoor air pollutants can completely enhance the internal exposure and indoor pollution has the same importance as outdoor pollution.