Winter aerosol and trace gas characteristics over a high-altitude station in the Western Ghats, India

This paper presents spectral distribution of aerosol optical depth (and derived size distribution), water vapor and ozone in total atmospheric column; in conjunction with particulate mass concentration in the size range from 0.3 to 20 μm and black carbon mass concentration at the surface-level during four different campaigns, conducted in months of December-January-2006-2007 (Campaign I), February-2007 (Campaign II), January-2008 (Campaign III) and November-2008 (Campaign IV) at a high-altitude station, Sinhgad (18°22'N, 73°45'E, 1450 m AMSL) in the Western Ghats of Indian Peninsula. Aerosol optical depth (AOD) measured within the spectral range 440-1020 nm is found lower as compared to that measured over a nearby urban station, Pune; but relatively higher than that over other remote high-altitude stations in India. The columnar Angstrom exponent derived within the 440-870 nm spectral range showed maximum values close to 1 indicating relatively higher contribution from fine-mode particles to aerosol size spectrum. Interestingly, this parameter shows lower values when the total aerosol mass concentration exhibits higher values during afternoon hours. Both columnar water vapor (CWV) and ozone (TCO) exhibit lower values in the morning hours and higher in the afternoon hours. The mass concentration of black carbon shows an association with AOD during the study period over the station. The measured surface aerosol particle number concentrations are used to reconstruct AOD spectra using the Optical Properties of Aerosols and Clouds (OPAC) software package and compared with simultaneously available columnar AOD spectra

Variation in the ionic composition in convective showers in Pune, India

Rain water samples of equal volume (100 ml) were collected sequentially from 5 convective shower events for a period of 2 years during the summer monsoon seasons of 1988 and 1989 at Pune. A marked decrease in the concentrations of soil-oriented elements Na+, K+, Ca2+ and Mg2+ was observed in the first few samples in all the events followed by a decrease in pH of the subsequent samples. Surprisingly, SO42- also showed similar variation, indicating that soil is contributing some SO42- in rain water. Washout process appears to be an important mechanism for the removal of the major ions from the atmosphere. However, rainout processes seem to be important for the removal of NO3- ions. The study points out that sequential sampling during a single shower appears to give better information about the relationship among H+, Na+, K+, Ca2+, Mg2+, SO42- and NO3- as compared to bulk sampling for longer duration

Sink mechanism for significantly low level of ozone over the Arabian Sea during monsoon

Measurement of surface ozone over the Arabian Sea during the southwest monsoon season (June-September) of 2002 has shown an unusually low level of ozone with an overall average of 9 nmol/mol. Such a low level of ozone could not be explained by simulations using a three-dimensional chemistry transport model, Model for Ozone and Related Tracers (MOZART), which accounts for the known processes of advective transport and includes a standard photochemical mechanism. Thus, for the Arabian Sea region, we propose for the first time that destruction of ozone by reactive halides released from sea salt aerosols is the sink mechanism which played a crucial role in ensuring the significantly low ozone level over the Arabian Sea. Theoretical calculations constrained by observations have shown that, on average, ozone losses due to catalytic action of halogens and due to photolysis plus chemical reaction amount to 2.15 nmol mol-1d-1 and 4.64 nmol mol-1d-1, respectively

The impact of advertisements: how female magazine readers in China perceive fashion magazine advertisements and white skin

Master of ScienceDepartment of Journalism and Mass CommunicationsXiaochen A. ZhangMost of the models in Chinese fashion magazine advertisements are Caucasian women today. White skin, as one of their Caucasian characteristics, is particularly emphasized. Millions of Chinese women are bombarded with the advertising’s message of “having white skin is beautiful” every day. My research suggests that this kind of adverting depicts white skin as a beauty ideal; the prevalence of Caucasian models in whitening products’ magazine advertisements constructs body-esteem, self-esteem, and purchase decision-making of Chinese women. The Social Judgment Theory is employed in this research as a theoretical framework. It is a way to explain when persuasive messages are most likely to succeed and how people make judgments about them. Understanding this phenomenon will ultimately provide insight into addressing the effects of the promotion of fashion magazine advertisements on Chinese women. It is further anticipated that future researchers will expand and improve the knowledge of the Chinese advertising market

Characteristics of aerosols at traffic junctions in Pune city

Vehicular emissions are one of the potential sources of air pollution in the urban regions. Pune, one of the rapidly growing cities of India, faces the severe threat from this problem. Observations of total suspended particulates and Aitken nuclei were conducted at 4 traffic junctions in Pune city during summer (May 2000) and winter (Jan-Feb. 2001). Concentrations of TSP crossed the CPCB limit, recommended for commercial zone, at all the traffic junctions and also the number density of Aitken nuclei was very high. However, aerosols were alkaline in nature, in spite of high concentrations of SO4 and NO3, mainly due to the neutralizing effect of Ca, NH4, Na, Mg and K

Radiocarbon-based source apportionment of elemental carbon aerosols at two South Asian receptor observatories over a full annual cycle

Black carbon (BC) aerosols impact climate and air quality. Since BC from fossil versus biomass combustion have different optical properties and different abilities to penetrate the lungs, it is important to better understand their relative contributions in strongly affected regions such as South Asia. This study reports the first year-round 14C-based source apportionment of elemental carbon (EC), the mass-based correspondent to BC, using as regional receptor sites the international Maldives Climate Observatory in Hanimaadhoo (MCOH) and the mountaintop observatory of the Indian Institute of Tropical Meteorology in Sinhagad, India (SINH). For the highly-polluted winter season (December–March), the fractional contribution to EC from biomass burning (fbio) was 53 ± 5% (n = 6) at MCOH and 56 ± 3% at SINH (n = 5). The fbio for the non-winter remainder was 53 ± 11% (n = 6) at MCOH and 48 ± 8% (n = 7) at SINH. This observation-based constraint on near-equal contributions from biomass burning and fossil fuel combustion at both sites compare with predictions from eight technology-based emission inventory (EI) models for India of (fbio)EI spanning 55–88%, suggesting that most current EI for Indian BC systematically under predict the relative contribution of fossil fuel combustion. A continued iterative testing of bottom-up EI with top-down observational source constraints has the potential to lead to reduced uncertainties regarding EC sources and emissions to the benefit of both models of climate and air quality as well as guide efficient policies to mitigate emissions

Year-round radiocarbon-based source apportionment of carbonaceous aerosols at two background sites in South Asia

Atmospheric Brown Clouds (ABC), regional-scale haze events, are a significant concern for both human cardiopulmonary health and regional climate impacts. In order to effectively mitigate this pollution-based phenomenon, it is imperative to understand the magnitude, scope and source of ABC in regions such as South Asia. Two sites in S. Asia were chosen for a 15-month field campaign focused on isotope-based source apportionment of carbonaceous aerosols in 2008-2009. Both the Maldives Climate Observatory in Hanimaadhoo (MCOH) and a mountaintop site in Sinhagad, India (SINH) act as regionally mixed receptor sites. Annual radiocarbon-based source apportionment for soot elemental carbon (SEC) at MCOH and SINH revealed 73 6 and 59 5 contribution from biomass combustion, respectively (remainder from fossil fuel). The contributions from biogenic/biomass combustion to total organic carbon were similar between MCOH and SINH (69 5 and 64 5, respectively). The biomass combustion contribution for SEC in the current study, especially the results from MCOH, shows good agreement with published black carbon emissions inventories for India. Geographic source assessment, including clustered back trajectory analysis and carbon contribution by source region, indicated that the highest SEC/TOC loads originated from the W. Indian coastal margin, including the coastal city of Mumbai, India. The winter dry season 14C-based source apportionment of the BC-tracing SEC fraction for 2006, 2008, 2009 were not statistically different (p = 0.7) and point to a near-constant two-thirds contribution from biomass combustion practices, including wood and other biofuels as well as burning of agricultural crop residues

Aerosol characteristics during winter fog at Agra, North India

Simultaneous measurements on physical, chemical and optical properties of aerosols over a tropical semi-arid location, Agra in north India, were undertaken during December 2004. The average concentration of total suspended particulates (TSP) increased by about 1.4 times during intense foggy/hazy days. Concentrations of SO4 2-, NO3 -, NH4 + and Black Carbon (BC) aerosols increased by 4, 2, 3.5 and 1.7 times, respectively during that period. Aerosols were acidic during intense foggy/hazy days but the fog water showed alkaline nature, mainly due to the neutralizing capacity of NH4 aerosols. Trajectory analyses showed that air masses were predominantly from NW direction, which might be responsible for transport of BC from distant and surrounding local sources. Diurnal variation of BC on all days showed a morning and an evening peak that were related to domestic cooking and vehicular emissions, apart from boundary layer changes. OPAC (Optical properties of aerosols and clouds) model was used to compute the optical properties of aerosols. Both OPAC-derived and observed aerosol optical depth (AOD) values showed spectral variation with high loadings in the short wavelengths (<1 μm). AOD value at 0.5 μm wavelength was significantly high during intense foggy/hazy days (1.22) than during clear sky or less foggy/hazy days (0.63). OPAC-derived Single scattering albedo (SSA) was 0.84 during the observational period, indicating significant contribution of absorbing aerosols. However, the BC mass fraction to TSP increased by only 1 during intense foggy/hazy days and thereby did not show any impact on SSA during that period. A large increase was observed in the shortwave (SW) atmospheric (ATM) forcing during intense foggy/hazy days (+75.8 W/m2) than that during clear sky or less foggy/hazy days (+38 W/m2), mainly due to increase in absorbing aerosols. Whereas SW forcing at surface (SUF) increased from -40 W/m2 during clear sky or less foggy/hazy days to -76 W/m2 during intense foggy/hazy days, mainly due to the scattering aerosols like SO4 2-

Studies of trace gases and Aitken Nuclei at inland and coastal stations - A part of INDOEX programme

As a part of the Indian Ocean Experiment (INDOEX) programme, ground-based measurements of trace gases (SO2, NO2, NH3 and O3) and Aitken Nuclei (AN) were carried out at Pune during March-April 1998. Also, measurements of surface ozone and AN were made during 5-10 January 1998, the inter comparison campaign of various instruments at Thiruvananthapuram. The mean concentrations of SO2, NO2, NH3 and O3 at Pune were 3.75, 5.81, 3.21 and 57.8 μg/m3 respectively and that of O3 at Thiruvananthapuram was 44 μg/m3. The average concentration of AN was about five times higher at Pune (19,000/cm3) than that at Thiruvananthapuram (4,400/cm3), indicating more pollution at Pune than at Thiruvananthapuram. The diurnal variation of surface ozone showed high concentrations during the day and low concentrations during the night at both the locations. Diurnal variation of AN at Pune showed a daytime maximum and a night-time minimum. Whereas, at Thiruvananthapuram night-time values were higher than the daytime values which can be attributed to the influence of the land and sea breeze

Atmospheric aerosol characteristic studies at Pune and Thiruvananthapuram during INDOEX programme - 1998

Total suspended particulates (TSP) and mass size distribution of aerosols were monitored by using a high-volume air sampler and a low-volume 9-stage Anderson sampler, respectively during March-April 1998 at Pune and during 5-9 January 1998 at Thiruvananthapuram. All these samples were extracted for water-and acid-soluble components using the standard extraction method. The water-soluble extracts were analysed for Cl, SO4, NO3, NH4, Na, K, Ca and Mg and acid-soluble extracts for Al, Fe, Mn, Cu, Zn, Pb, Cd, Ni and Sb. The concentration of TSP varied from 67 to 185 μg/m3 with an average of 122 μg/m3 at Pune and from 35 to 73 μg/m3 with an average of 57 μg/m3 at Thiruvananthapuram. The mass size distribution of aerosols showed bimodal distribution having one peak in coarse mode and the other in fine mode at both the locations. The results of the study are presented here