Study of surface morphology, elemental composition and origin of atmospheric aerosols (PM2.5 and PM10) over Agra, India

In situ measurements of PM (PM2.5 and PM10) particles were carried out using a medium volume air sampler (offline) and particle number concentrations of PM were measured by a Grimm aerosol spectrophotometer (online) during the study period of 2010�2011. The morphology and elemental composition analyses of PM were performed by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometry (EDS), respectively. The average mass concentrations of PM2.5 and PM10 were 97.2 and 242.6 µg/m3 at roadside (RD) and 121.2 and 230.5 µg/m3 at a semirural (SR) site, respectively. These concentrations were substantially higher than the NAAQS, WHO and USEPA standards. The highest mass and number concentrations of PM2.5 and PM10 were observed during winter, followed by those during the post-monsoon period and summer, with the lowest in the monsoon period. SEM and EDS analysis of PM indicated the presence of soot, mineral, tarballs, fly ash, aluminosilicates/silica, fluorine, carbon rich, and Cl-Na rich particles. Of these particles, soot, tarballs, and F-C rich particles dominate in PM2.5, whereas mineral, aluminosilicates, and Cl-Na rich particles dominate in PM10. The morphology and elemental composition of the particles varied over the seasons due to atmospheric processing. The highest carbon concentration (56) was observed in PM2.5 during summer at the RD, while in the monsoon, post-monsoon period and winter the carbon concentration was ~9 lower at the RD as compared to the SR. However, the concentration of carbon in PM10 was ~38 higher at the RD as compared to SR during both summer and winter. Air mass backward trajectory cluster analysis was performed, and the results indicate that the aerosol loadings over Agra are mainly transported from the Middle East and Arabian Sea during the summer and monsoon period, while during the pre-monsoon period and winter the aerosol loadings came from the northern region, and were due to the burning of biomass and coal, as well as other local activities

Sources and characteristics of carbonaceous aerosols at Agra World heritage site and Delhi capital city of India

Agra, one of the oldest cities “World Heritage site”, and Delhi, the capital city of India are both located in the border of Indo-Gangetic Plains (IGP) and heavily loaded with atmospheric aerosols due to tourist place, anthropogenic activities, and its topography, respectively. Therefore, there is need for monitoring of atmospheric aerosols to perceive the scenario and effects of particles over northern part of India. The present study was carried out at Agra (AGR) as well as Delhi (DEL) during winter period from November 2011 to February 2012 of fine particulate (PM2.5: d < 2.5 μm) as well as associated carbonaceous aerosols. PM2.5 was collected at both places using medium volume air sampler (offline measurement) and analyzed for organic carbon (OC) and elemental carbon (EC). Also, simultaneously, black carbon (BC) was measured (online) at DEL

Variability in atmospheric particulates and meteorological effects on their mass concentrations over Delhi, India

Simultaneous and continuous measurements of PM2.5 and PM10 along with other co-existent pollutants viz., black carbon (BC), CO, NO and NOx were carried out over Delhi with high resolution (5 min) datasets from 1st Sept. 2010 to 23rd Aug. 2012. Arithmetic mean mass concentrations of PM2.5 and PM10 were about 130 ± 103 and 222 ± 142 μg m− 3 respectively during the entire measurement period, which are considerably higher than the annual averages of PM2.5 and PM10, stipulated by the National and International standards. It was noticed that the fine mode particles (PM2.5) were higher than the coarse mode particles (PM10–2.5) during post-monsoon (~ 89%), winter (~ 69%) and monsoon (~ 64%) periods; however, PM10–2.5 was higher (~ 22%) than PM2.5 during summer. Arithmetic mean mass concentrations of BC, CO, NO and NOx were about 7 ± 5 μg m− 3, 2 ± 1 ppm, 17 ± 17 ppb and 30 ± 24 ppb, respectively. In the present study, highest fraction of BC (~ 6%) in PM2.5 mass was in winter, whereas the lowest fraction (~ 4%) was in summer. Relationships among PMs (particulate matters) and other pollutants indicated that the fine mode particles are highly correlated with BC (0.74) and CO (0.51

A maize histone deacetylase and retinoblastoma-related protein physically interact and cooperate in repressing gene transcription

In mammalian cells the product of the human retinoblastoma tumour suppressor gene (pRb) can recruit Rpd3-like histone deacetylases to repress transcription. In this study, we investigated whether this mechanism might also be relevant in plants and found both conserved and distinct features. The expression profiles of the Zea mays Rpd3- type histone deacetylase (ZmRpd3I) and the retinoblastoma-related (ZmRBR1) homologues were analysed during endosperm development. GST pull-down and immunoprecipitation experiments showed a physical interaction between ZmRBR1 and ZmRpd3I. Because ZmRpd3I lacks a LXCXE motif, conserved in several pRb-interacting proteins, we have mapped the amino acid domains involved in the ZmRBR1/ZmRpd3I interaction. Furthermore, we observed that ZmRbAp1, a maize member of the MSI/RbAp family, facilitated this protein interaction. Cotransformations of tobacco protoplasts with plasmids expressing ZmRBR1 and ZmRpd3I showed that the two proteins cooperate in repressing gene transcription. Our findings represent the first indication that in plants a regulator of important biological processes, ZmRBR1, can recruit a histone deacetylase, ZmRpd3I, to control gene transcription