Wintertime characteristics of aerosols at middle Indo-Gangetic Plain: Impacts of regional meteorology and long range transport

Kumar, Manish; Tiwari, S.; Murari, Vishnu; Singh, Abhay Kumar; Banerjee, Tirthankar

doi:10.1016/j.atmosenv.2015.01.014

Cited by 86 publications

(37 citation statements)

References 36 publications

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“…Results reveal that the study regions are generally characterized by westerly to northwesterly winds during the study period, with relatively higher speed during monsoon and post-monsoon. Similar results are also observed by during pre-monsoon season and by Kumar et al (2015) during high aerosol loading days in winter season. A significant gradient in RH was observed over the region during the study period.…”

Section: Site Description and Synoptic Condition Over Igbsupporting

confidence: 92%

Identification of aerosol types over Indo-Gangetic Basin: implications to optical properties and associated radiative forcing

Tiwari

Srivastava

Singh

et al. 2015

Environ Sci Pollut Res

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The aerosols in the Indo-Gangetic Basin (IGB) are a mixture of sulfate, dust, black carbon, and other soluble and insoluble components. It is a challenge not only to identify these various aerosol types, but also to assess the optical and radiative implications of these components. In the present study, appropriate thresholds for fine-mode fraction and single-scattering albedo have been used to first identify the aerosol types over IGB. Four major aerosol types may be identified as polluted dust (PD), polluted continental (PC), black carbon-enriched (BCE), and organic carbon-enriched (OCE). Further, the implications of these different types of aerosols on optical properties and radiative forcing have been studied. The aerosol products derived from CIMEL sun/sky radiometer measurements, deployed under Aerosol Robotic Network program of NASA, USA were used from four different sites Karachi, Lahore, Jaipur, and Kanpur, spread over Pakistan and Northern India. PD is the most dominant aerosol type at Karachi and Jaipur, contributing more than 50% of all the aerosol types. OCE, on the other hand, contributes only about 12-15% at all the stations except at Kanpur where its contribution is ∼38%. The spectral dependence of AOD was relatively low for PD aerosol type, with the lowest AE values (<0.5); whereas, large spectral dependence in AOD was observed for the remaining aerosol types, with the highest AE values (>1.0). SSA was found to be the highest for OCE (>0.9) and the lowest for BCE (<0.9) type aerosols, with drastically different spectral variability. The direct aerosol radiative forcing at the surface and in the atmosphere was found to be the maximum at Lahore among all the four stations in the IGB.

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Section: Site Description and Synoptic Condition Over Igbsupporting

confidence: 92%

Identification of aerosol types over Indo-Gangetic Basin: implications to optical properties and associated radiative forcing

Tiwari

Srivastava

Singh

et al. 2015

Environ Sci Pollut Res

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“…5d, e) allows for accumulation of aerosols as air masses flow to the southeast across the high-emission IGP region (e.g., Nair et al, 2007;Kumar et al, 2015;Sen et al, 2017). Nair et al (2007) highlights the role of this transport mechanism by showing PM 2.5 levels in the IGP increased with the distance the air mass had traveled from the west.…”

Section: Daily Variabilitymentioning

confidence: 99%

Exploring the relationship between surface PM<sub>2.5</sub> and meteorology in Northern India

et al. 2018

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Abstract. Northern India (23)(24)(25)(26)(27)(28)(29)(30)(31) • N, 68-90 • E) is one of the most densely populated and polluted regions in world. Accurately modeling pollution in the region is difficult due to the extreme conditions with respect to emissions, meteorology, and topography, but it is paramount in order to understand how future changes in emissions and climate may alter the region's pollution regime. We evaluate the ability of a developmental version of the new-generation NOAA GFDL Atmospheric Model, version 4 (AM4) to simulate observed wintertime fine particulate matter (PM 2.5 ) and its relationship to meteorology over Northern India. We compare two simulations of GFDL-AM4 nudged to observed meteorology for the period 1980-2016 driven by pollutant emissions from two global inventories developed in support of the Coupled Model Intercomparison Project Phases 5 (CMIP5) and 6 (CMIP6), and compare results with ground-based observations from India's Central Pollution Control Board (CPCB) for the period 1 October 2015-31 March 2016. Overall, our results indicate that the simulation with CMIP6 emissions produces improved concentrations of pollutants over the region relative to the CMIP5-driven simulation.While the particulate concentrations simulated by AM4 are biased low overall, the model generally simulates the magnitude and daily variability of observed total PM 2.5 . Nitrate and organic matter are the primary components of PM 2.5 over Northern India in the model. On the basis of correlations of the individual model components with total observed PM 2.5 and correlations between the two simulations, meteorology is the primary driver of daily variability. The model correctly reproduces the shape and magnitude of the seasonal cycle of PM 2.5 , but the simulated diurnal cycle misses the early evening rise and secondary maximum found in the observations. Observed PM 2.5 abundances are by far the highest within the densely populated IndoGangetic Plain, where they are closely related to boundary layer meteorology, specifically relative humidity, wind speed, boundary layer height, and inversion strength. The GFDL AM4 model reproduces the overall observed pollution gradient over Northern India as well as the strength of the meteorology-PM 2.5 relationship in most locations.

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“…Regarding other sites in IGP region, PM 2.5 / PM 10 ratios were reported to be 56 % in Kanpur (Snider et al, 2016), 60 % in Varanasi (Kumar et al, 2015), D. Rupakheti et al: Pre-monsoon air quality over Lumbini 57 % in Guwahiti (Tiwari et al, 2017), 90 % in Dribugarh (Pathak et al, 2013) and 62 % in Delhi , indicating local differences within IGP as well as suggesting that the influence of combustion sources at Lumbini is still lower compared to other locations in the Indian section of the IGP. A recent study (Putero et al, 2015) reported that the PM 1 / PM 10 during pre-monsoon of 2013 was found to be 0.39 in the Kathmandu Valley of Nepal.…”

Section: Meteorologymentioning

confidence: 99%

Pre-monsoon air quality over Lumbini, a world heritage site along the Himalayan foothills

et al. 2017

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Abstract. Lumbini, in southern Nepal, is a UNESCO world heritage site of universal value as the birthplace of Buddha. Poor air quality in Lumbini and surrounding regions is a great concern for public health as well as for preservation, protection and promotion of Buddhist heritage and culture. We present here results from measurements of ambient concentrations of key air pollutants (PM, BC, CO, O 3 ) in Lumbini, first of its kind for Lumbini, conducted during an intensive measurement period of 3 months (April-June 2013) in the pre-monsoon season. The measurements were carried out as a part of the international air pollution measurement campaign; SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley -Atmospheric Brown Clouds). The main objective of this work is to understand and document the level of air pollution, diurnal characteristics and influence of open burning on air quality in Lumbini. The hourly average concentrations during the entire measurement campaign ranged as follows: BC was 0.3-30.0 µg m −3 , PM 1 was 3.6-197.6 µg m −3 , PM 2.5 was 6.1-272.2 µg m −3 , PM 10 was 10.5-604.0 µg m −3 , O 3 was 1.0-118.1 ppbv and CO was 125.0-1430.0 ppbv. These levels are comparable to other very heavily polluted sites in South Asia. Higher fraction of coarsemode PM was found as compared to other nearby sites in the Indo-Gangetic Plain region. The BC / CO ratio obtained in Lumbini indicated considerable contributions of emissions from both residential and transportation sectors. The 24 h average PM 2.5 and PM 10 concentrations exceeded the WHO guideline very frequently (94 and 85 % of the sampled period, respectively), which implies significant health risks for the residents and visitors in the region. These air pollutants exhibited clear diurnal cycles with high values in the morning and evening. During the study period, the worst air pollution episodes were mainly due to agro-residue burning and regional forest fires combined with meteorological conditions conducive of pollution transport to Lumbini. Fossil fuel combustion also contributed significantly, accounting for more than half of the ambient BC concentration according to aerosol spectral light absorption coefficients obtained in Lumbini. WRF-STEM, a regional chemical transport model, was used to simulate the meteorology and the concentrations of pollutants to understand the pollutant transport pathways. The model estimated values were ∼ 1.5 to 5 times lower than the observed concentrations for CO and PM 10 , respectively. Model-simulated regionally tagged CO tracers showed that the majority of CO came from the upwind region of Ganges Valley. Model performance needs significant improvement Published by Copernicus Publications on behalf of the European Geosciences Union.

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Wintertime characteristics of aerosols at middle Indo-Gangetic Plain: Impacts of regional meteorology and long range transport

Cited by 86 publications

References 36 publications

Identification of aerosol types over Indo-Gangetic Basin: implications to optical properties and associated radiative forcing

Identification of aerosol types over Indo-Gangetic Basin: implications to optical properties and associated radiative forcing

Exploring the relationship between surface PM<sub>2.5</sub> and meteorology in Northern India

Pre-monsoon air quality over Lumbini, a world heritage site along the Himalayan foothills

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Wintertime characteristics of aerosols at middle Indo-Gangetic Plain: Impacts of regional meteorology and long range transport

Cited by 86 publications

References 36 publications

Identification of aerosol types over Indo-Gangetic Basin: implications to optical properties and associated radiative forcing

Identification of aerosol types over Indo-Gangetic Basin: implications to optical properties and associated radiative forcing

Exploring the relationship between surface PM&lt;sub&gt;2.5&lt;/sub&gt; and meteorology in Northern India

Pre-monsoon air quality over Lumbini, a world heritage site along the Himalayan foothills

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Exploring the relationship between surface PM<sub>2.5</sub> and meteorology in Northern India