Aerosol chemical characterization and role of carbonaceous aerosol on radiative effect over Varanasi in central Indo-Gangetic Plain

Tiwari, Suresh; Dumka, U. C.; Kaskaoutis, Dimitris G.; Ram, Kirpa; Panicker, A. S.; Srivastava, Manoj; Tiwari, S.; Attri, S. D.; Soni, V. K.; Pandey, Apoorva

doi:10.1016/j.atmosenv.2015.07.031

Cited by 63 publications

(25 citation statements)

References 105 publications

(171 reference statements)

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“…The coarse-mode (PM 10-2.5 ) fraction was ∼ 60 % of the PM 10 . The share of coarse-mode aerosol to PM 10 in Lumbini was higher than that observed in other sites in the IGP, such as Guwahiti, India (42 %) (Tiwari et al, 2017), and Dibrugarh, India (9-16 %) (Pathak et al, 2013), both in eastern IGP and Delhi (38 %) in western IGP, indicating the higher contribution of coarse aerosols in Lumbini, likely lifted from soils from nearby agricultural fields and construction materials by stronger winds during pre-monsoon season.…”

Section: Meteorologycontrasting

confidence: 61%

“…In Lumbini, the average (hourly) share of PM 1 in PM 2.5 , PM 1 in PM 10 and PM 2.5 in PM 10 was found to be ∼ 70, 34 and 47 %, respectively. 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), 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: 97%

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Compiled Response to the reviewers comments

Rupakheti¹

2017

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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 improvementPublished by Copernicus Publications on behalf of the European Geosciences Union. 11042 D. Rupakheti et al.: Pre-monsoon air quality over Lumbini in simulating aerosols in the region. Given the high air pollution level, there is a clear and urgent need for setting up a network of long-term air quality monitoring stations in the greater Lumbini region.

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Section: Meteorologycontrasting

confidence: 61%

Section: Meteorologymentioning

confidence: 97%

Compiled Response to the reviewers comments

Rupakheti¹

2017

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“…The contribution of BC in PM 1 was found to be ∼ 12 % in Kanpur during February-March (Kumar et al, 2016a), similar to Lumbini. Regarding the share of BC in PM 10 , the share observed in Lumbini (∼ 4 %) was similar to that observed over Varanasi (∼ 340 km south of our site) in central IGP (5 %) (Tiwari et al, 2016) and Dibrugarh in eastern IGP (∼ 5 %) (Pathak et al, 2013). Thus our results indicate that despite our station being located at the northern edge of the IGP along the foothills of the Himalayan range, the share of BC in PM is similar to that found in heavily polluted sites in the central and eastern IGP.…”

Section: Meteorologymentioning

confidence: 52%

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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“…The higher concentrations found in the intensive campaigns have already been attributed to biomass burning in previous studies (Pereira et al, 2017;Vasconcellos et al, 2011a). However, potassium ions can also come from soil resuspension (Ram et al, 2010;Tiwari et al, 2016), which becomes important in PM 2.5−10 . Higher concentrations of chloride in fine particles (964 and 330 ng m −3 for Int 2.5 and Ext 2.5 , respectively) were observed in the Int 2.5 campaign (although the value of p was slightly above 0.05), probably due to a higher influence of biomass burning .…”

Section: Wsi and Trace Elementsmentioning

confidence: 87%

Particulate pollutants in the Brazilian city of São Paulo: 1-year investigation for the chemical composition and source apportionment

et al. 2017

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Abstract. São Paulo in Brazil has relatively relaxed regulations for ambient air pollution standards and often experiences high air pollution levels due to emissions of particulate pollutants from local sources and long-range transport of air masses impacted by biomass burning. In order to evaluate the sources of particulate air pollution and related health risks, a year-round sampling was done at the University of São Paulo campus (20 m a.g.l.), a green area near an important expressway. The sampling was performed for PM 2.5 (≤ 2.5 µm) and PM 10 (≤ 10 µm) in 2014 through intensive (everyday sampling in wintertime) and extensive campaigns (once a week for the whole year) with 24 h of sampling. This year was characterized by having lower average precipitation compared to meteorological data, and high-pollution episodes were observed all year round, with a significant increase in pollution level in the intensive campaign, which was performed during wintertime. Different chemical constituents, such as carbonaceous species, polycyclic aromatic hydrocarbons (PAHs) and derivatives, water-soluble ions, and biomass burning tracers were identified in order to evaluate health risks and to apportion sources. The species such as PAHs, inorganic and organic ions, and monosaccharides were determined using chromatographic techniques and carbonaceous species using thermal-optical analysis. Trace elements were determined using inductively coupled plasma mass spectrometry. The risks associated with particulate matter exposure based on PAH concentrations were also assessed, along with indexes such as the benzo[a]pyrene equivalent (BaPE) and lung cancer risk (LCR). High BaPE and LCR were observed in most of the samples, rising to critical values in the wintertime. Also, biomass burning tracers and PAHs were higher in this season, while secondarily formed ions presented low variation throughout the year. Meanwhile, vehicular tracer species were also higher in the intensive campaign, suggesting the influence of lower dispersion conditions in that period. Source apportionment was performed using positive matrix factorization (PMF), which indicated five different factors: road dust, industrial emissions, vehicuPublished by Copernicus Publications on behalf of the European Geosciences Union. 11944 G. M. Pereira et al.: Particulate pollutants in the Brazilian city of São Paulo lar exhaust, biomass burning and secondary processes. The results highlighted the contribution of vehicular emissions and the significant input from biomass combustion in wintertime, suggesting that most of the particulate matter is due to local sources, in addition to the influence of pre-harvest sugarcane burning.

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Aerosol chemical characterization and role of carbonaceous aerosol on radiative effect over Varanasi in central Indo-Gangetic Plain

Cited by 63 publications

References 105 publications

Compiled Response to the reviewers comments

Compiled Response to the reviewers comments

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

Particulate pollutants in the Brazilian city of São Paulo: 1-year investigation for the chemical composition and source apportionment

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