The present study was carried out to determine the contamination levels of heavy metals in road dust of the National Capital Territory of Delhi (NCT), India and its consequent effect on human and ...environment. The levels of heavy metals (Pb, Zn, Cu, Cr, Ni, Mn, and Fe) in 9 districts (Z1–Z9) of NCT were monitored and the corresponding human health risk was estimated. District-wise evaluation of heavy metal pollution in the road dust was performed. The mean concentrations of Pb, Zn, Cu, Ni, Cr, Mn, and Fe in the road dust samples over the study area were 164.2 ± 53.2, 200.7 ± 45.3, 99.9 ± 64.8, 24.7 ± 5.7, 57.7 ± 25.9, 241.4 ± 39.8, and 11113.9 ± 1669.7 mg kg
−1
, respectively. PLI showed a high pollution load in the monitored nine locations, indicating an alarming condition and the urgent need for immediate remedial actions. Ecological risk assessment depicted that a 74% risk was attributed to Pb. Hazard quotient (HQ) values indicated that ingestion was the major pathway of road dust heavy metal exposure to human beings. Hazard index values showed that there was no probable non-carcinogenic risk of the heavy metals present in the road dust of the area. Children were found vulnerable to the risks of road dust metals. The findings of this study showed the alarming status of heavy metal contamination to road dust in NCT and the associated risk to human health.
Heavy metals are persistent and bio-accumulative, and pose potential risk to human health and ecosystem. We reviewed the current state of heavy metal contamination, the ecotoxicological and human ...health risk of heavy metals reported in urban road dust from various cities in different continents (Asia, Europe, Africa, America, and Australia). We compared and synthesized the findings on the methods related to sample collection, extraction, analytical tools of heavy metals, their concentrations, level of contamination, ecological risk, non-carcinogenic risk, and carcinogenic risk in road dust. Concentrations of Pb, Zn, Cu, Ni, Cd, Cr, Mn, and Fe were found to be higher than their background values in soil. As expected, the contamination levels of the heavy metals varied extensively among cities, countries, continents, and periods. A high level of contamination is observed for Pb and Cd in road dust due to operating leaded gasoline and the old vehicle population. The highest Zn contamination was observed from road dust in Europe, followed by Asia, Africa, Australia, and America (North America and South America). Cu contamination and the pollution load index (
PLI
) is found to be the highest in Europe and lowest in Africa, with in-between values of
PLI
in American and African cities. The potential ecological risk on different continents was observed highest in Asia, followed by Europe, Australia, America, and Africa. A comparative assessment of non-carcinogenic risk for children indicated that Australia is the most susceptible country due to high heavy metal exposure in road dust, followed by Asia. However, there is no susceptible risk in European, African, and American cities. We did not observe any potential risk to adults due to non-carcinogenic metals. Carcinogenic risk to all age groups was within the threshold limit range for all the regions worldwide.
Fine aerosol fraction (particulate matter with aerodynamic diameter <= 1.0 μm (PM)
1.0
) over the Indian Institute of Technology Delhi campus was monitored day and night (10 h each) at 30 m height ...from November 2009 to March 2010. The samples were analyzed for 5 ions (NH
4
+
, NO
3
−
, SO
4
2−
, F
−
, and Cl
−
) and 12 trace elements (Na, K, Mg, Ca, Pb, Zn, Fe, Mn, Cu, Cd, Cr, and Ni). Importantly, secondary aerosol (sulfate and nitrate) formation was observed during dense foggy events, supporting the fog-smog-fog cycle. A total of 76 samples were used for source apportionment of PM mass. Six factors were resolved by PMF analyses and were identified as secondary aerosol, secondary chloride, biomass burning, soil dust, iron-rich source, and vehicular emission. The geographical location of the sources and/or preferred transport pathways was identified by conditional probability function (for local sources) and potential source contribution function (for regional sources) analyses. Medium- and small-scale metal processing (e.g. steel sheet rolling) industries in Haryana and National Capital Region (NCR) Delhi, coke and petroleum refining in Punjab, and thermal power plants in Pakistan, Punjab, and NCR Delhi were likely contributors to secondary sulfate, nitrate, and secondary chloride at the receptor site. The agricultural residue burning after harvesting season (Sept–Dec and Feb–Apr) in Punjab, and Haryana contributed to potassium at receptor site during November–December and March 2010. The soil dust from North and East Pakistan, and Rajasthan, North-East Punjab, and Haryana along with the local dust contributed to soil dust at the receptor site, during February and March 2010. A combination of temporal behavior and air parcel trajectory ensemble analyses indicated that the iron-rich source was most likely a local source attributed to emissions from metal processing facilities. Further, as expected, the vehicular emissions source did not show any seasonality and was local in origin.
Delhi, India, routinely experiences some of the world's highest urban
particulate matter concentrations. We established the Delhi Aerosol Supersite
study to provide long-term
characterization of the ...ambient submicron aerosol composition in Delhi. Here
we report on 1.25 years of highly time-resolved speciated submicron
particulate matter (PM1) data, including black carbon (BC) and
nonrefractory PM1 (NR-PM1), which we combine to develop a
composition-based estimate of PM1
(“C-PM1” = BC + NR-PM1) concentrations. We observed marked seasonal and diurnal variability in the concentration and
composition of PM1 owing to the interactions of sources and atmospheric
processes. Winter was the most polluted period of the year, with average
C-PM1 mass concentrations of ∼210 µg m−3. The monsoon was hot and rainy, consequently
making it the least polluted (C-PM1 ∼50 µg m−3) period. Organics constituted more than half
of the C-PM1 for all seasons and times of day. While ammonium, chloride,
and nitrate each were ∼10 % of the C-PM1 for the cooler
months, BC and sulfate contributed ∼5 % each. For the warmer
periods, the fractional contribution of BC and sulfate to C-PM1
increased, and the chloride contribution decreased to less than 2 %. The
seasonal and diurnal variation in absolute mass loadings were generally
consistent with changes in ventilation coefficients, with higher
concentrations for periods with unfavorable meteorology – low
planetary boundary layer height and low wind speeds. However, the variation
in C-PM1 composition was influenced by temporally varying sources,
photochemistry, and gas–particle partitioning. During cool periods when wind
was from the northwest, episodic hourly averaged chloride concentrations
reached 50–100 µg m−3, ranking
among the highest chloride concentrations reported anywhere in the world. We estimated the contribution of primary emissions and secondary processes to
Delhi's submicron aerosol. Secondary species contributed
almost 50 %–70 % of Delhi's C-PM1 mass for the
winter and spring months and up to 60 %–80 % for the warmer summer
and monsoon months. For the cooler months that had the highest C-PM1
concentrations, the nighttime sources were skewed towards primary sources,
while the daytime C-PM1 was dominated by secondary species. Overall,
these findings point to the important effects of both primary emissions and
more regional atmospheric chemistry on influencing the extreme particle
concentrations that impact the Delhi megacity region. Future air quality
strategies considering Delhi's situation in both a regional
and local context will be more effective than policies targeting only local,
primary air pollutants.
Absorption by light‐absorbing carbon (LAC) particles increases when the carbon is mixed with other material, and this change affects climate forcing. We investigate this increase theoretically over a ...realistic range of particle sizes. Perfect mixing at the molecular level often overestimates absorption. Assuming that LAC is coated by a concentric shell of weakly absorbing material, we calculate absorption by a range of realistic particle sizes and identify regimes in which absorption behaves similarly. We provide fits to amplification in five regions: (1) small cores and (2) intermediate cores, both with large shells; (3) small to intermediate cores with intermediate shells; (4) cores with growing shells; and (5) intermediate to large cores with large shells. Amplification in region 1 is highest but is physically implausible. Amplification in region 5 is constant at about 1.9 and represents an asymptote for particles with broad size distributions. Because absorption by aggregates is amplified by about 1.3 above spherical particles, and that factor is lost when particles are coated, we suggest that absorption by aged aerosol is about 1.5 times greater than that of fresh aerosol. The rate at which particles acquire sufficient coating to increase their original diameter by 60% is important in determining total absorption during their atmospheric lifetimes. Fitted amplification factors are not very sensitive to assumed refractive index of LAC and can be used even in simple models.
This study examined the PM
10
and PM
2.5
concentration, associated mortality, and transport pathways in Ghaziabad which is an industrial city in the Indo-Gangetic Plain. To achieve this, PM (both PM
...10
and PM
2.5
) and meteorological parameters were measured from June 2018 to May 2019 at 2 locations and analyzed together with data from a 3rd location in Ghaziabad. The highest daily average PM
10
and PM
2.5
concentrations were ~ 1000 µg m
−3
and ~ 450 µg m
−3
, respectively. At each of the three locations, the annual mean PM
10
concentrations were ~ 260 ± 150 µg m
−3
while the PM
2.5
concentrations were 140 ± 90 µg m
−3
. Nonparametric Spearman rank correlation analysis between meteorological parameters and PM concentrations indicated that ventilation coefficient was anti-correlated with PM concentration during the post-monsoon and winter seasons (the most polluted seasons) with rank correlation values of approximately − 0.50. Multiple linear regression (MLR) revealed that the variability in local meteorological parameters account for ~ 50% variability (maximum) in PM
10
mass during the monsoon and PM
2.5
during the post-monsoon season. For long-range sources, cluster and concentrated weighted trajectory (CWT) analyses utilizing regional meteorology showed the impact of transported PM from sources in Arabian sea through western India in monsoon and from parts of South Asia through Northwestern IGP and neighboring cities in Uttar Pradesh in other seasons. Finally, mortality estimates show that the number of deaths attributable to ambient PM
2.5
in Ghaziabad were ~ 873 per million individuals which was ~ 70% higher than Delhi.
India implemented a range of multifarious strategies to address the issue of substandard air quality. One such flagship scheme of government of India is National Clean Air Programme (NCAP), which ...recommends sector specific reduction in emissions and increase in forest cover etc. To reduce particulate matter concentrations by 40% in 2026 compared to 2019. The present study aims to gauge the impact of Land Use Land Cover (LULC) changes alone on success of NCAP, using weather research forecasting model with chemistry (WRF-Chem) and integrated geographical information system and remote sensing software Terrset. The findings elucidate that, by the year 2026, the Ventilation Coefficient (VC) in India's eastern, central, northern, and north-eastern regions is anticipated to register a decline ranging from 18% to 50% compared to the baseline year of 2019. Conversely, an increase of 17% is expected in the southern region. The alterations in Fallow Land, Barren and sparsely vegetated land, Urban and Built-up Land, and Tundra, contribute to these shifts, displaying varying percentage changes across distinct zones. Simulations indicate that these LULC changes are impeding the planned reduction in PM2.5 levels. Projections suggest an increase in PM2.5 levels as high as 13% in the eastern, central, northern, and north-eastern regions, accompanied by a decrease of 33% in the Southern zone of the country. Significantly, non-attainment cities in Himachal Pradesh and Maharashtra are expected to witness a substantial rise in PM2.5-induced premature mortality, with Pune city projected to experience over 24,525 additional premature deaths by 2026. A comparable examination conducted for the year 2022, utilizing actual LULC data, suggests that if the NCAP fails to effectively implement LULC changes, it may reduce this anticipated trade-off. Addressing this concern, the study employed WRF-Chem to simulate 60 combinations, proposing LULC enhancements conducive to improving VC. The results underscore the critical importance of preserving at least 36% of the LULC category of mixed forest land, encompassing plantations, orchards, and areas under shifting agriculture. Additionally, a reduction in barren land and fallow land emerges as pivotal for enhancing the ventilation coefficient. The study accentuates the necessity of refraining from further expansion in densely populated areas to counter these anticipated VC trends. This study provides valuable insights, highlighting the need to prioritize LULC management to effectively combat the alarming air pollution.
Display omitted
•Diminished VC in some zones owing to the upsurge in fallow land and urban area.•LULC changes counteract NCAP's PM2.5 reduction from 3% in north to 10% in west.•Maximum increase in premature mortality is expected in Pune city.•36% forest land and no additional built-up area needed to improve VC trends.
In this study, the air pollution–related quality of life (AP-QOL) questionnaire was carried out in two geographically and economically different groups including New Delhi (Megacity) and Hamirpur, ...Himachal Pradesh (town), and APE scores were linked with respiratory and cardiovascular illness. The APE-Score was developed by AP-QOL questionnaire responses using Delphi technique and further analyzed using principal component analysis (PCA). For reliability of APE-Score and AP-QOL questionnaire, α-Cronbach’s test and basic statistics were performed. The linear mixed-effect model and odds ratios were used to evaluate air pollution exposure and health outcomes. Overall, 720 academicians and 276 security guards were invited to participate in the questionnaire. Cronbach’s α coefficients ranged from 0.70 to 0.84 indicated significant reliability in the AP-QOL questionnaire conducted in this study. Substantial variation in respiratory symptoms and their medical history were found − 76.9% (95% confidential interval (CI): (− 83.8, − 66.9) (
p
< 0.05)) and − 28.6% (95% CI: (− 37.8, − 18.0) (
p
< 0.05)), respectively, with interquartile range (IQR) increase of APE score. The odds ratios (ORs) of respiratory medical history (MH Res.) showed a significant increase from 1.01 to 1.35 for low to high air pollution exposure in the academic group of IIT Delhi. Interestingly, for an academic group of NITH, the ORs for medical history of cardiovascular (MH Card.) showed an increase from 1.08 to 1.13 for low to high APE which was not the case for IIT Delhi academicians.
This study presents the emission factor of gaseous pollutants （CO, CO2, and NOx） from on-road tailpipe measurement of 14 passenger cars of different types of fuel and vintage. The trolley equipped ...with stainless steel duct, vane probe velocity meter, flue gas analyzer, Nondispersive infra red （NDIR） C02 analyzer, temperature, and relative humidity （RH） sensors was connected to the vehicle using a towing system. Lower CO and higher NOx emissions were observed from new diesel cars （post 2010） compared to old cars （post 2005）, which implied that new technological advancement in diesel fueled passenger cars to reduce CO emission is a successful venture, however, the use of turbo charger in diesel cars to achieve high temperature combustion might have resulted in increased NOx emissions. Based on the measured emission factors （g/kg0, and fuel consumption （kg）, the average and 95% confidence interval （CI） bound estimates of CO, CO2, and NOx from four wheeler （4W） in Delhi for the year 2012 were 15.7 （1.4-37.1）, 6234 （386-12,252）, and 30.4 （0.0-103） Gg/year, respectively. The contribution of diesel, gasoline and compressed natural gas （CNG） to total CO, C02 and NOx emissions were 7：84：9, 50：48：2 and 58：41：1 respectively. The present work indicated that the age and the maintenance of vehicle both are important factors in emission assessment therefore, more systematic repetitive measurements coveting wide range of vehicles of different age groups, engine capacity, and maintenance level is needed for refining the emission factors with CI.
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