Temporal variation of Black Carbon concentration using Aethalometer observations and its relationships with meteorological variables in Karachi, Pakistan

Bibi, Samina; Alam, Khan; Chishtie, Farrukh; Bibi, Humera; Rahman, Said

doi:10.1016/j.jastp.2017.03.017

Cited by 32 publications

(20 citation statements)

References 28 publications

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“…Increased wintertime emissions from heating sources and combustion of biomass in addition to low boundary layer heights may have contributed to high concentrations of BC at Tibet Center. These observations are consistent with several other studies examining BC concentrations in Karachi [23,25]. In contrast, these studies also observed better dispersion of pollutants because of increased boundary layer heights and enriched wet deposition during summer monsoon rainfall [26][27][28].…”

Section: Daily Mean Black Carbon Concentrationssupporting

confidence: 92%

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Short-Term Association between Black Carbon Exposure and Cardiovascular Diseases in Pakistan’s Largest Megacity

et al. 2018

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This study investigated the association between black carbon (BC) exposure and hospital admissions (HAs) and outpatient department/emergency room (OPD/ER) visits for cardiovascular diseases (CVD) among residents of Karachi, the largest city in Pakistan. We measured daily concentrations of BC in fine particulate matter (PM2.5) and collected records of HAs and OPD/ER visits for CVD from 2 major tertiary care hospitals serving Karachi for 6 weeks continuously during each quarter over 1 year (August 2008–August 2009). We subsequently analyzed daily counts of hospital and BC data over 0–3 lag days. Daily mean BC concentrations varied from 1 to 32 µg/m3. Results suggest that BC concentrations are associated with CVD HAs and OPD/ER visits. However, associations were generally only observed when modeled with BC from Tibet Center, the commercial-residential site, as compared to Korangi, the industrial-residential site. Overall, low statistical significance suggests that while BC may be a valuable indicator for CVD health risks from combustion-derived particles, further evaluation of the constituents of PM2.5 and their relative contributions to CVD health impacts is necessary.

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Section: Daily Mean Black Carbon Concentrationssupporting

confidence: 92%

“…Throughout the study period, BC emissions were highest during business hours and when traffic flow was at its greatest intensity. Bibi et al [25] similarly observed high BC morning peaks, which they attributed to anthropogenic activities such as traffic and industrial activities.…”

Section: Daily Mean Black Carbon Concentrationsmentioning

confidence: 97%

Short-Term Association between Black Carbon Exposure and Cardiovascular Diseases in Pakistan’s Largest Megacity

et al. 2018

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“…Wind speed increases significantly with height, measuring two-fold higher at 350 m than at ground level. High wind speeds likely contribute to the decrease in eBC with height (Bibi et al 2017). The eBC episode during December 9-10 was likely driven primarily by the low wind speed during this period, confirming the key role of wind speed, among other meteorological factors, in the observed eBC concentrations.…”

Section: Effect Of Meteorological Factors On Ebc Temporal Variationssupporting

confidence: 53%

Time-resolved black carbon aerosol vertical distribution measurements using a 356-m meteorological tower in Shenzhen

Sun

et al. 2020

Theor Appl Climatol

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Black carbon (BC) is an essential climate forcer in the atmosphere. Large uncertainties remain in BC's radiative forcing estimation by models, partially due to the limited measurements of BC vertical distributions near the surface layer. We conducted time-resolved vertical profiling of BC using a 356-m meteorological tower in Shenzhen, China. Five micro-aethalometers were deployed at different heights (2, 50, 100, 200, and 350 m) to explore the temporal dynamics of BC vertical profile in the highly urbanized areas. During the observation period (December 6-15, 2017), the average equivalent BC (eBC) concentrations were 6.6 ± 3.6, 5.4 ± 3.3, 5.9 ± 2.8, 5.2 ± 1.8, and 4.9 ± 1.4 μg m −3 , from 2 to 350 m, respectively. eBC temporal variations at different heights were well correlated. eBC concentrations generally decreased with height. At all five heights, eBC diurnal variations exhibited a bimodal pattern, with peaks appearing at 09:00-10:00 and 19:00-21:00. The magnitudes of these diurnal peaks decreased with height, and the decrease was more pronounced for the evening peak. eBC episodes were largely initiated by low wind speeds, implying that wind speed played a key role in the observed eBC concentrations. eBC wind-rose analysis suggested that elevated eBC events at different heights originate from different directions, which suggested contributions from local primary emission plumes. Air masses from central China exhibited much higher eBC levels than the other three backward trajectory clusters found herein. The absorption Ångström exponent (AAE 375-880) showed clear diurnal variations at 350 m and increased slightly with height.

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“…The literature under this study identified that Lahore is the most highly studied city regarding air pollution monitoring and investigation [8,9,11,14,21,32,34,40,[43][44][45][46], followed by Islamabad [2,10,12,17,35,[47][48][49][50][51][52], Karachi [38,39,41,44,53], Peshawar [18,44], Quetta [7], Faisalabad [3], Swat [16], and Wah [13]. A countrywide study pertaining to atmospheric emission was also undertaken by Shahid [15], to investigate seasonal variations of aerosols (sulfate, nitrate, ammonium, organic carbon, black carbon, and PM 2.5 ), and its contributions towards domestic anthropogenic and transboundary transport emissions.…”

Section: Air Quality and Atmospheric Pollution In Pakistan: A Brief Lmentioning

confidence: 94%

“…BC aerosol is notorious for its radiative properties, i.e., they absorb visible and infrared wavelengths and are responsible for climate perturbation. Thus, BC is one of the most climatologically significant components of PM 2.5 [38,39].…”

Section: Air Quality and Atmospheric Pollution In Pakistan: A Brief Lmentioning

confidence: 99%

Cleaner and Sustainable Energy Production in Pakistan: Lessons Learnt from the Pak-TIMES Model

et al. 2019

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The energy planning process essentially requires addressing diverse planning objectives, including prioritizing resources, and the estimation of environmental emissions and associated health risks. This study investigates the impacts of atmospheric pollution for Pakistan from the energy production processes under various modalities. A national-scale bottom-up energy optimization model (Pak-TIMES) with the ANSWER-TIMES framework is developed to assess the electricity generation pathways (2015–2035) and estimate GHG emissions and major air pollutants, i.e., CH4, CO, CO2, N2O, NOX, PM1, PM10, PM2.5, PMBC, PMOC, PMTSP, SO2, and VOC under five scenarios. These scenarios are: BAU (business-as-usual), RE-30 (30% renewables), RE-40 (40% renewables), Coal-30 (30% coal), and Coal-40 (40% coal). It is revealed that to reach the electricity demand of 3091 PJ in 2035, both the Coal-30 and Coal-40 scenarios shall cause maximum emissions of GHGs, i.e., 260.13 and 338.92 Mt (million tons) alongside 40.52 and 54.03 Mt emissions of PMTSP in both of the scenarios, respectively. BAU scenario emissions are estimated to be 181.5 Mt (GHGs) and 24.30 Mt (PMTSP). Minimum emissions are estimated in the RE-40 scenario with 96.01 Mt of GHGs and 11.80 Mt of PMTSP, followed by the RE-30 scenario (143.20 GHGs and 17.73 Mt PMTSP). It is, therefore, concluded that coal-based electricity generation technologies would be a major source of emission and would contribute the highest amount of air pollution. This situation necessitates harnessing renewables in the future, which will significantly mitigate public health risks from atmospheric pollution.

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Temporal variation of Black Carbon concentration using Aethalometer observations and its relationships with meteorological variables in Karachi, Pakistan

Cited by 32 publications

References 28 publications

Short-Term Association between Black Carbon Exposure and Cardiovascular Diseases in Pakistan’s Largest Megacity

Short-Term Association between Black Carbon Exposure and Cardiovascular Diseases in Pakistan’s Largest Megacity

Time-resolved black carbon aerosol vertical distribution measurements using a 356-m meteorological tower in Shenzhen

Cleaner and Sustainable Energy Production in Pakistan: Lessons Learnt from the Pak-TIMES Model

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