Anubha Goel

Annual trends in occurrence of submicron particles in ambient air and health risk posed by particle bound metals

Risk analysis is highly important in toxicology and public health studies. Health risk related to exposure to toxic metals of PM1 was assessed. Concentrations of 13 heavy metals, adsorbed to submicron particulate matter PM1 were experimentally examined but only 12 metals were found at detectable levels inside IIT Kanpur campus in 2008-2009 for all months excluding June and October. A total of 90 samples collected for 8 h sampling time by a single stage round nozzle, grease impaction substrate based impactor type PM1 sampler were analysed by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry). Results showed daily average PM1 concentration is 102.46 ± 35.9 μg/m(3) and metal concentration followed the trend: Ca > Fe > Mg > Zn > Pb > Cu > Cr > Ni > Se > Cd > V > As. Contamination level assessment using geo-accumulation index showed Ca, Fe and Mg exhibited non contamination whereas metals like Cr, Zn, As, Cd, Pb, Se, Ni and Cu exhibited ranges from moderate to extreme contamination. Ingestion is found to be the major exposure pathway for heavy metals. Non-carcinogenic health risk assessment for Pb, Cd and Cr (HI > 1) signified strong chances of adverse impact on children whereas adults are well under safe limit. Cancer Risk for adults and children followed the same decreasing order, Cr(VI)>Cd > Ni > As > Pb. It was found to be higher than permissible limits (10(-6)) for adults and children both.

Determination of vapor pressure-temperature relationships of current-use pesticides and transformation products.

Sub-cooled liquid vapor pressures (PL 0) of current–use organochlorine and organophosphate pesticides (chlorothalonil, chlorpyrifos methyl, diazinon, fipronil) and selected transformation products (chlorpyrifos oxon, heptachlor epoxide, oxychlordane, 3,5,6-trichloro-2-pyridinol) were determined at multiple temperatures using the gas chromatography retention time technique. Results were utilized to determine vapor pressure-temperature relationships and to calculate enthalpies of vaporization (ΔHvap). While results for chlorothalonil and diazinon were comparable with published values, the measured value for fipronil (1.82 × 10− 6 Pa) is almost an order of magnitude higher than the reported literature value (3.7 × 10− 7 Pa). The availability of vapor pressure temperature relationships for these chemicals will aid in pesticide risk assessment development and improve the effectiveness of mitigation and remediation efforts.

Elevated Aerosol Layers and Their Radiative Impact over Kanpur During Monsoon Onset Period

Accurate information about aerosol vertical distribution is needed to reduce uncertainties in aerosol radiative forcing and its effect on atmospheric dynamics. The present study deals with synergistic analyses of aerosol vertical distribution and aerosol optical depth (AOD) with meteorological variables using multisatellite and ground-based remote sensors over Kanpur in central Indo-Gangetic Plain (IGP). Micro-Pulse Lidar Network-derived aerosol vertical extinction (σ) profiles are analyzed to quantify the interannual and daytime variations during monsoon onset period (May–June) for 2009–2011. The mean aerosol profile is broadly categorized into two layers viz., a surface layer (SL) extending up to 1.5 km (where σ decreased exponentially with height) and an elevated aerosol layer (EAL) extending between 1.5 and 5.5 km. The increase in total columnar aerosol loading is associated with relatively higher increase in contribution from EAL loading than that from SL. The mean contributions of EALs are about 60%, 51%, and 50% to total columnar AOD during 2009, 2010, and 2011, respectively. We observe distinct parabolic EALs during early morning and late evening but uniformly mixed EALs during midday. The interannual and daytime variations of EALs are mainly influenced by long-range transport and convective capacity of the local emissions, respectively. Radiative flux analysis shows that clear-sky incoming solar radiation at surface is reduced with increase in AOD, which indicates significant cooling at surface. Collocated analysis of atmospheric temperature and aerosol loading reveals that increase in AOD not only resulted in surface dimming but also reduced the temperature (∼2–3∘C) of lower troposphere (below 3 km altitude). Radiative transfer simulations indicate that the reduction of incoming solar radiation at surface is mainly due to increased absorption by EALs (with increase in total AOD). The observed cooling in lower troposphere in high aerosol loading scenario could be understood as a dynamical feedback of EAL-induced stratification of lower troposphere. Further, the observed radiative effect of EALs increases the stability of the lower troposphere, which could modulate the large-scale atmospheric dynamics during monsoon onset period. These findings encourage follow-up studies on the implication of EALs to the Indian summer monsoon dynamics using numerical models.

Study of Environmental Particle Levels, Its Effects on Lung Deposition and Relationship With Human Behaviour

The adverse impact of particulate matter (PM) on human health can be best explained in terms of PM deposition inside respiratory organs rather than the typically reported ambient exposure concentration. This study measured the PM mass concentration (MC) at various microenvironments inside a residential campus and estimated the corresponding PM mass deposition in human respiratory regions such as Head (H), tracheobronchial (TB) and pulmonary (P) organs. This was done using the Multiple Path Particle Dosimetry lung model. Particle size fractions in the range of 0.25–10 μm were measured by an optical particle counter during winter when the PM MC is significantly high. The results showed that MC varied widely at different microenvironments ranging from 169.7 to 604.9 μg/m3 for PM1 and 31.2 to 649 μg/m3 for PM10−1. The highest and lowest MC for both fine and coarse sizes were found in the canteen and library, respectively. Our model revealed that the total deposited fraction increased with higher physical activity (e.g. higher breathing rate). The deposition fraction increased consistently in the Head with increase in particle size for all physical activity levels, whereas it varied in the P region. Results for 24 h lung dosimetry computed for students displayed that the dose deposition for coarse size particles for all type of activities followed the same trend: H > P > TB. A similar trend was found for fine particles except during sleep and sit activity levels with dissimilar trend: P > H > TB. The total deposited dose was found highest at play court while lowest at canteen. This type of focused preliminary study is much needed as physical activity levels and time spent at particular microenvironment besides the PM exposure concentration and helps to determine the critical microenvironments.