Chemical characteristics of aerosols and trace gas distribution over North and Central India

Abstract

A field campaign on aerosol chemical properties and trace gases measurements was carried out along the Delhi-Hyderabad-Delhi road corridor (spanning about 3,200 km) in India, during February 1-29, 2004. Aerosol particles were collected on quartz and cellulose filters using high volume (PM(10)) sampler at various locations along the route (i.e., urban, semi-urban, rural, and forest areas) and have been characterized for major cations (Na(+), Ca(2+), Mg(2+), K(+), and NH (4) (+)), anions (Cl(-), NO (3)(-), and SO (4)(2-)), and heavy metals (Cu, Cd, Fe, Zn, Mn, and Pb). Simultaneously, we measured NO(2) and SO(2) gases. These species show large spatial and temporal variations. The ambient PM(10) concentration has been observed to be the highest (55 ± 4 μg m(-3)) near semi-urban areas followed by forest areas (48 ± 2 μg m(-3)) and in rural areas (44 ± 22 μg m(-3)). The concentrations of NO( x ) (NO(2)+NO) and SO(2) ranged from 16 to 69 μg m(-3) and 4 to 11 μg m(-3), respectively. Among anions, NO(3)(-) and SO(4) (2-) are the major constituents of PM(10). The urban and semi-urban sites showed enhanced concentrations of Fe, Zn, Mn, Cd, and Pb. This study provide information about atmospheric concentrations of various species in the northern to central India, which may be important for policy makers to better understand the air quality of the region.

Seasonal Variation of Saccharides and Furfural in Atmospheric Aerosols at a Semi-Urban Site

“…However, there are important limitations of potassium in the use of the marker, because potassium also has many sources, such as biomass burning, coal/charcoal burning, soil dust, fertilizers, and even traffic exhaust emissions in small amounts (Andreae and Merlet, 2001;Urban et al, 2012). Seasonal variations in the particulate matter mass and chemical composition depend on factors such as emission/ transformation rates, distance from the source, physical conditions of the medium where they are introduced (Perrino et al, 2010;Singh et al, 2012;Ni et al, 2013;Saitanis et al, 2013) and meteorological conditions (e.g., mixing depth of the atmosphere, rainfall, wind speed and prevailing wind direction). Soil and vegetation particles are mostly resuspended during summers, secondary pollutants, produced by precursor reactions in the atmosphere, rapidly increase during periods of atmospheric stability, and domestic heating during cold periods (Perrino et al, 2013).…”

Oxidation and Reduction

“…The rate is retarded by OH − ions but increases on addition of (MeCO 2 ) 2 Hg (Br − ion scavenger) suggesting that Hg 2+ probably acts as a catalyst. 181 The similar oxidation of BPA to the corresponding carboxylic acid in 50 : 50 AcOH-H 2 O is first order in NBA, BPA, and H + ion. The rate decreases with acetamide but increases with lowering of the dielectric constant.…”

“…336 A review of the development of optically active cobalt complex catalysts for enantioselective synthetic reactions has addressed the applications of ketoiminatocobalt(II) complexes such as (S)-MPAC (179) Me enantioselective cyclopropanation and its theoretical analysis, and spin-transition models of cobalt complexes, and so on. 337 A cobaltacyclopentene intermediate, formed by the catalyst CoI 2 and the ligand (R)-2-(diphenylphosphino)-1-(2-(diphenylphosphino)naphthalen-1-yl)naphthalene, (BINAP) (181), in the presence of Zn (reductant), ZnI 2 (Lewis acid), H 2 O (H + source), and 1,4-dioxane (solvent) is effective for inter-molecular asymmetric reductive coupling of alkynes with cyclic enones to produce highly regio-and enantioselective β-alkenyl cyclic ketones in good yield with high ee values. 338 ee The Ni(COD) 2 /PCy 3 -catalysed and Et 3 SiH-mediated reductive cyclization of ynals in THF is first order in catalyst and ynal and zero order in silane, which was used only in the presence of alkyne and aldehyde.…”

Global Radiation, Transmissivity and Bright Sunshine Hour Trend over Nagpur in Pre-Monsoon and Monsoon Seasons

“…With increase in population and to satisfy the need of increasing population many industries are spreading day by day and these urbanizations, industrialization and other anthropogenic activities are contributing more in aerosol load in the atmosphere. Nagpur which is a big city represents a typical urban area with population of about 4.05 million [23]. Aerosols from transport sector, industries and biomass burning are the main sources of anthropogenic aerosols.…”