Contribution of fossil and biomass-derived secondary organic carbon to winter water-soluble organic aerosols in Delhi, India.

Delhi, among the world's most polluted megacities, is a hotspot of particulate matter emissions, with high contribution from organic aerosol (OA), affecting health and climate in the entire northern India. While the primary organic aerosol (POA) sources can be effectively identified, an incomplete source apportionment of secondary organic aerosol (SOA) causes significant ambiguity in the management of air quality and the assessment of climate change. Present study uses positive matrix factorization analysis on the water-soluble organic aerosol (WSOA) data from the offline-aerosol mass spectrometry (AMS).

Molecular distribution, sources and potential health risks of fine particulate-bound polycyclic aromatic hydrocarbons during high pollution episodes in a subtropical urban city.

Abundance of fine particulate-bound 16 priority polycyclic aromatic hydrocarbons (PAHs) was investigated to ascertain its sources and potential carcinogenic health risks in Varanasi, India. The city represents a typical urban settlement of South Asia having particulate exposure manyfold higher than standard with reports of pollution induced mortalities and morbidities. Fine particulates (PM) were monitored from October 2019 to May 2020, with 32% of monitoring days accounting ≥100 μgm of PM concentration, frequently from November to January (99% of monitoring days).

Insights into size-segregated particulate chemistry and sources in urban environment over central Indo-Gangetic Plain.

Size-segregated airborne fine (PM) and coarse (PM) particulates were measured in an urban environment over central Indo-Gangetic plain in between 2015 and 2018 to get insights into its nature, chemistry and sources. Mean (±1σ) concentration of PM was 98 (±76) μgm with a seasonal high during winter (DJF, 162 ± 71 μgm) compared to pre-monsoon specific high in PM (MAMJ, 177 ± 84 μgm) with an annual mean of 170 (±69) μgm. PM was secondary in nature with abundant secondary inorganic aerosols (20% of particulate mass) and water-soluble organic carbon (19%) against metal enriched (25%) PM, having robust signature of resuspensions from Earth's crust and road dust.

Source apportionment and health risk assessment of airborne particulates over central Indo-Gangetic Plain.

Sources of airborne particulates (PM) were investigated in two contrasting sites over central Indo-Gangetic Plain (IGP), one representing a rural background (Mirzapur) and another as an urban pollution hotspot (Varanasi). Very high PM concentration was noted both in Varanasi (178 ± 105 μgm; N:435) and Mirzapur (131 ± 56 μgm; N:169) with 72% and 62% of monitoring days exceeded the national air quality standard, respectively. Particulate-bound elements contribute significant proportion of PM mass (15%-18%), with highest contribution from Ca (7%-10%) and Fe (2%-3%).

Airborne particulate in Varanasi over middle Indo-Gangetic Plain: variation in particulate types and meteorological influences.

The variation in particulate mass and particulate types (PM and PM) with respect to local/regional meteorology was analyzed from January to December 2014 (n = 104) for an urban location over the middle Indo-Gangetic Plain (IGP). Both coarser (mean ± SD; PM 161.3 ± 110.

Fine particulates over South Asia: Review and meta-analysis of PM source apportionment through receptor model.

Fine particulates (PM) constitute dominant proportion of airborne particulates and have been often associated with human health disorders, changes in regional climate, hydrological cycle and more recently to food security. Intrinsic properties of particulates are direct function of sources. This initiates the necessity of conducting a comprehensive review on PM sources over South Asia which in turn may be valuable to develop strategies for emission control.

Temporal variability of MODIS aerosol optical depth and chemical characterization of airborne particulates in Varanasi, India.

Temporal variation of airborne particulate mass concentration was measured in terms of toxic organics, metals and water-soluble ionic components to identify compositional variation of particulates in Varanasi. Information-related fine particulate mass loading and its compositional variation in middle Indo-Gangetic plain were unique and pioneering as no such scientific literature was available. One-year ground monitoring data was further compared to Moderate Resolution Imaging Spectroradiometer (MODIS) Level 3 retrieved aerosol optical depth (AOD) to identify trends in seasonal variation.

Massive intrapericardial herniation of stomach following pericardial window.

Herniation of intra-abdominal contents into the pericardial cavity is rare. We describe one such case occurring after creation of a pericardioperitoneal window for drainage of a pericardial effusion. The diagnosis of an intrapericardial hernia should be considered in patients presenting with gastrointestinal and/or cardiorespiratory symptoms following surgical procedures involving the diaphragm.

Aneurysm of sinus of Valsalva dissecting into interventricular septum.

Background: Dissection of interventricular septum by aneurysm of the sinus of Valsalva is extremely rare. We present our experience with the management of 10 patients with this condition.

Methods: Ten patients with aneurysm of the sinus of Valsalva dissecting into the interventricular septum were managed at All India Institute of Medical Sciences, New Delhi, between May 1987 and September 1996.