Comparative investigation of coal- and oil-fired boilers based on emission factors, ozone and secondary organic aerosol formation potentials of VOCs.

Volatile organic compounds (VOCs) are the important precursors of the tropospheric ozone (O3) and secondary organic aerosols (SOA), both of which are known to harm human health and disrupt the earth's climate system. In this study, VOC emission factors, O3 and SOA formation potentials were estimated for two types of industrial boilers: coal-fired boilers (n = 3) and oil-fired boilers (n = 3). Results showed that ∑VOCs concentrations were more than nine times higher for oil-fired boilers compared to those for coal-fired boilers. Emission factors of ∑VOCs were found to be higher for oil-fired boilers (9.26-32.83 mg-VOC/kg) than for coal-fired boilers (1.57-4.13 mg-VOC/kg). Alkanes and aromatics were obtained as the most abundant groups in coal-fired boilers, while oxygenated organics and aromatics were the most contributing groups in oil-fired boilers. Benzene, n-hexane and o-ethyl toluene were the abundant VOC species in coal-fired boiler emissions, whereas toluene was the most abundant VOC species emitted from oil-fired boilers. O3 and SOA formation potentials were found 12 and 18 times, respectively, higher for oil-fired than for coal-fired boilers. Total OFP ranged from 3.99 to 11.39 mg-O3/kg for coal-fired boilers. For oil-fired boilers, total OFP ranged from 36.16 to 131.93 mg-O3/kg. Moreover, total secondary organic aerosol potential (SOAP) ranged from 65.4 to 122.5 mg-SOA/kg and 779.9 to 2252.5 mg-SOA/kg for the coal-fired and oil-fired boilers, respectively.

Dependence of urban air pollutants on morning/evening peak hours and seasons.

Traffic emission is a major source of air pollution in urban cities of developing world. This paper shows dependence of traffic-related air pollutants in urban cities on morning/evening peak hours and winter/summer seasons. This research also shows the meteorological impact, such as temperature (T), relative humidity (RH), and wind speed (WS), on traffic-related air pollutants in urban cites. Based on the research output, the elevated level of PM concentration was observed between 1.8 and 6.7 times at all nearby roadway locations compared with background (IIT [ISM] campus). We have found 2.3, 2.4, 2.6 (morning) and 2.0, 2.1, and 2.1 (evening) times higher average PM10, PM2.5, and PM1 concentrations, respectively, in the winter than summer monitoring periods across all locations, due to the stable boundary layer, lower mixing height, and lower friction velocity. It is indicated that urban meteorology plays a crucial role in increasing or decreasing exposed pollutant concentrations in various microenvironments. The analysis of PM2.5/PM10 ratios was lower during whole campaign due to higher contribution of coarser particles generated by vehicles. During winter and summer seasons, 0.57 and 0.33 was observed, respectively. It is indicated that 57% and 33% of PM10 makes up PM2.5 particle, respectively. PM concentrations have showed a negative linear relationship with T and WS and positive relationship with RH in winter/summer seasons. Therefore, traffic and meteorology play a big role to increase or decrease in traffic-related air pollutants in urban air quality.

Influence of Road Paving on Particulate Matter Emission and Fingerprinting of Elements of Road Dust.

Most assessments of road dust have focused largely on the resuspension of materials from the paved road while the contribution from unpaved shoulder to particulate matter is poorly understood. We evaluated the role of unpaved road shoulders in the contribution of particulate matter emitted by analyzing elements in the road dust. We collected road dust samples and employed US-EPA empirical equations. The results of TSP emission reveal that unpaved shoulder adjacent to paved roads (43.1-29.9%) is a potential emitter than that at roundabouts (27%). In paved road environment, the contribution of TSP emission was 54.9-25.6% from unpaved shoulders based on driving share of vehicles. TSP emission results suggest that waste material is frequently exchanged from paved to unpaved shoulder, which leads to seasonal variations in paved road. The observed particle size of paved surface waste material shows that about 36% particles were less than 2.5 µm and 52% were greater than 10 µm, suggesting that dust is resuspendable and presents a health risk due to being respirable. Elemental analysis confirmed the presence of the toxic elements Cr, Ni, Cu, Zn, Pb, Sn, Sb, and Ba in waste material. Moreover, receptor models indicate that the waste material comprised of elements from tire wear (31%), mineral dust (27%), brake wear (17%), vehicle exhaust (14%), and coal (7%). The elemental contribution of coal is a location-specific source identified from principal component analysis and hierarchical cluster analysis, which originated spillage during transportation. The study illustrates the contributions of PM emission from the different road networks and the mechanism of exchange of waste materials. Microscopic observation of resuspension and transportation of road dust due to vehicular movement leads to advection mechanism at the roundabout and the paved road having unpaved shoulders.

Impact Assessment of Atmospheric Dust on Foliage Pigments and Pollution Resistances of Plants Grown Nearby Coal Based Thermal Power Plants.

Plant species grown in the vicinity of thermal power plants (TPP) are one of the immobile substrates to sink most of the pollutants emitted from their stacks. The continuous exposure of toxic pollutants to these plants may affect their resistances and essential biochemical's concentrations. In the present study, we estimated the impact of dust load generated by a TPPs to plant's dust retention capacity and pollution resistances (APTI and API). The observed ambient air quality index (AQI) showed that the surroundings of TPPs are in the severe air pollution category. Observed AQI was greater than 100 in the surrounding area of TPP. The mean dust load on plant foliage was significantly greater in the polluted site compared with the control site: 4.45 ± 1.96 versus 1.38 ± 0.41 mg cm-2. Nearby, TPP highest and lowest dust load were founded in F. benghalensis (7.58 ± 0.74) and F. religiosa (2.25 ± 0.12 mg cm-2) respectively. Analysis revealed the strong negative correlation between dust load and essential pigments of foliage, such as chlorophyll content, carotenoids, pH of foliage extract, and relative water content. Conversely, strong positive correlation was observed with the ascorbic acid content of plant species. Correlation and percentage change analysis in ascorbic acid content for the polluted site against the control site showed the adverse impact on plants due to dust load. Based on their responses to dust pollution, A. scholaris, P. longifolia, and M. indica were observed as most suitable plant species. Estimation of DRC, chlorophyll a/b ratio, APTI and API revealed the A. scholaris, F. benghalensis, P. longifolia, and M. indica as the most suitable plant species for green belt formation. The high gradation was obtained in A. scholaris, F. benghalensis, P. longifolia, and M. indica for opted parameters and showed their most suitability for green belt formation. Salient features of the present study provide useful evidences to estimate the combined effect of DRC and pollution resistances of plant species on green belt establishment for long-term environmental management around industries.

Characterization of indoor settled dust and investigation of indoor air quality in different micro-environments.

Present study reports the characterization results of settled dust particles in different indoor micro-environments of an academic institution in India. Field emission scanning electron microscope analysis of indoor dust revealed the presence of mineral particles, fly ash, and soot particles of different morphologies. Energy-dispersive X-ray spectroscopy analysis of indoor dust indicated that crystal particles are comprised of elements such as C, O, Na, Mg, Al, Si, S, Cl, K, Ca, Fe, and Ti. These elements accounted for more than 99% of the samples. The average content of O (42.7%) and C (18.9%) in the dust particles was found to be higher than their natural abundances. The concentrations of PM10, PM2.5, and PM1 were observed in the range of 88-58, 37-33, 23-29 µg/m3, respectively. Except temperature, other parameters such as volatile organic carbon, carbon dioxide concentration, and relative humidity were found to be within comfort limits of American Society of Heating, Refrigerating, and Air-Conditioning Engineers. ABBREVIATIONS: ASHRAE: American Society of Heating, Refrigerating, and Air-Conditioning Engineers; CO2: carbon dioxide; COPD: chronic obstructive pulmonary disease; EDX: energy-dispersive X-ray; FESEM: field emission scanning electron microscope; FTIR: Fourier transform infrared spectroscopy; IAP: indoor air pollution; IAQ: indoor air quality; HAP: household air pollution; OAP: outdoor air pollution; PM: particulate matter; VOC: volatile organic carbon; WHO: World Health Organization.

VOC source apportionment, reactivity, secondary transformations, and their prioritization using fuzzy-AHP method in a coal-mining city in India.

This study assessed the air quality status in different functional zones of Dhanbad-a coal-mining and industrial hub, based on the measurement of aromatic and halogenated volatile organic compounds (VOCs) using gas chromatography. The study encompasses source apportionment of VOCs and their chemical reactivity in terms of OH radical loss rate (LOH), ozone-forming potential (OFP), and their secondary organic aerosol forming potential (SOAp). Furthermore, prioritization of VOCs based on a fuzzy-analytical hierarchical process (F-AHP) has also been done. The results found xylene species to have the highest concentration in all three seasons across traffic-intersection and industrial zones and toluene at the institutional zone. The study identified four sources using positive matrix factorization (PMF) model, viz., mixed traffic exhaust (35%), coal combustion sources (30%), industrial (26%), and solvent usage (9%). LOH and SOAp were ~ 16 times more at the industrial and traffic-intersection zone than the institutional zone. The aromatic species contributed 97% to the OFP, and many species exhibited less contribution to the mixing ratio of VOCs but displayed a high contribution to LOH, OFP, and SOAp, suggesting the need to prefer reactivity-based strategies in addition to concentration-based strategies in the future for their regulation. The F-AHP-based priority component analysis identified 16 species out of 29 in the priority watch list (nine in tier-1, four in tier-2, and three in tier-3). The paucity of data and lack of ambient air quality standards on VOCs (except benzene) make it difficult to determine which aspect should be dealt with first and which species require more attention. Therefore, the F-AHP method used in this study could help identify the influencing parameters to be considered while devising efficient VOC management policies.

Health risk assessment from exposure to ambient VOCs and particulate matter in different functional zones in Dhanbad, India.

This study evaluates the non-cancer risks (NCR) and cancer risks (CR) in outdoor working personnel in Dhanbad city, exposed to volatile organic compounds (VOCs) and particulate matter (PM) present in the ambient air. Dhanbad is known for its coal mines and is one of the most polluted cities in India and the world. Sampling was conducted in different functional zones; namely, traffic intersections, industrial, and institutional areas, to estimate the concentration of different PM-bound heavy metals and VOCs in the ambient air using Inductively coupled plasma-optical emission spectrometry (ICP-OES) and gas chromatography (GC) respectively. Our results show that the concentration levels (of VOCs and PM) and health risks were maximum at the traffic intersection area, followed by the industrial and institutional areas. The major contribution to CR came from chloroform, naphthalene, and PM-bound chromium, while the contribution to NCR mainly came from naphthalene, trichloroethylene, xylenes, and PM-bound chromium, nickel, and cadmium. It was observed that CR and NCR from VOCs are quite comparable (average CRvoc 8.92E-05 and NCRvoc 6.82) to that from the PM-bound heavy metals (average CRPM 9.93E-05 and NCRPM 3.52). According to the sensitivity analysis performed using Monte-Carlo Simulation, it was also found that the output risk is most significantly influenced by the pollutant concentration followed by exposure duration and exposure time. The study reveals that Dhanbad city is not only a critically polluted area but also a highly hazardous and cancer-prone area due to the pollution arising from incessant coal mining activities and heavy vehicular movement. Given the paucity of data on exposure to VOCs in ambient air and their risk assessment pertaining to coal mining cities of India, our study provides useful information and insight for the regulatory and enforcing authorities to devise appropriate strategies for air pollution and health risk management in such cities.

Assessment of Pollution and Health Risks of Heavy Metals in Particulate Matter and Road Dust Along the Road Network of Dhanbad, India.

BACKGROUND: The rise in particulate matter (PM) concentrations is a serious problem for the environment. Heavy metals associated with PM10, PM2.5, and road dust adversely affect human health. Different methods have been used to assess heavy metal contamination in PM10, PM2.5, and road dust and source apportionment of these heavy metals. These assessment tools utilize pollution indices and health risk assessment models. OBJECTIVES: The present study evaluates the total mass and average concentrations of heavy metals in PM10, PM2.5, and road dust along selected road networks in Dhanbad, India, analyzes the source apportionment of heavy metals, and assesses associated human health risks. METHODS: A total of 112 PM samples and 21 road dust samples were collected from six stations and one background site in Dhanbad, India from December 2015 to February 2016, and were analyzed for heavy metals (iron (Fe), lead (Pb), cadmium (Cd), nickel (Ni), copper (Cu), chromium (Cr), and zinc (Zn)) using atomic absorption spectrophotometry. Source apportionment was determined using principal component analysis. A health risk assessment of heavy metal concentrations in PM10, PM2.5, and road dust was also performed. RESULTS: The average mass concentration was found to be 229.54±118.40 µg m-3 for PM10 and 129.73 ±61.74 µg m-3 for PM2.5. The average concentration of heavy metals was found to be higher in PM2.5 than PM10. The pollution load index value of PM10 and PM2.5 road dust was found to be in the deteriorating category. Vehicles were the major source of pollution. The non-carcinogenic effects on children and adults were found to be within acceptable limits. The heavy metals present in PM and road dust posed a health risk in the order of road dust> PM10> and PM2.5. Particulate matter posed higher health risks than road dust due to particle size. CONCLUSIONS: The mass concentration analysis indicates serious PM10 and PM2.5 contamination in the study area. Vehicle traffic was the major source of heavy metals in PM10, PM2.5, and road dust. In terms of non-carcinogenic risks posed by heavy metals in the present study, children were more affected than adults. The carcinogenic risk posed by the heavy metals was negligible. COMPETING INTERESTS: The authors declare no competing financial interests.

Identifying Speed Hump, a Traffic Calming Device, as a Hotspot for Environmental Contamination in Traffic-Affected Urban Roads.

Despite several studies on traffic calming devices, information on particulate matter contribution by vehicle abrasion and wear nearby vertical deflections of speed humps is scant. Many studies have been performed in the recent past on heavy metal contamination at roads mainly at intersections. On the other hand, the traffic calming devices were studied for their effectiveness in reducing the vehicle speed and thereby increasing road safety, but their environmental effects are neglected. In the present study, the relation between the concentrations of Cu and Zn (marker heavy metals for traffic sources) at speed humps were nearly thrice to that in intersections, while for another marker heavy metal Pb, it was found nearly twice in comparison. Pollution load index >3 was observed upto 7.5-8.8 m distances of speed humps, and these were identified as hotspot zones for traffic-generated pollution. Furthermore, this heavy-metal-laden speed hump soil can pose a threat to living beings by virtue of resuspension produced by vehicular movements. Therefore, it is necessary to manage this emerging environmental issue, and we propose a traffic calming device with wheel cut-out provision for different vehicle classes as an alternate.

Size-segregated particulate matter and its association with respiratory deposition doses among outdoor exercisers in Dhanbad City, India.

Regular exercise improves physiological processes and yields positive health outcomes. However, it is relatively less known that particulate matter (PM) exposure during outdoor exercises may increase several respiratory health problems depending on PM levels. In this study, the respiratory deposition doses (RDDs) in head airway (HD), tracheobronchial (TB), and alveolar (AL) regions of various PM size fractions (<10, <2.5, and <1 µm; PM10, PM2.5, and PM1) were estimated in healthy male and female exercisers in urban outdoors and within house premises. The highest RDDs were found for PM during morning hours in winter compared with remaining periods. RDDs in AL region for males and females, respectively, were 34.7 × 10-2 and 28.8 × 10-2 µg min-1 for PM10, 65.7 × 10-2 and 56.9 × 10-2 µg min-1 for PM2.5, and 76.5 × 10-2 and 66.3 × 10-2 µg min-1 for PM1. The RDD values in AL region were significantly higher in PM1 (27%) compared with PM2.5 (13%) and PM10 (2%) during exercise in all periods. This result showed that the morning peak hours in winter are more harmful to urban outdoor exercisers compared with other periods. This study also showed that the AL region would have been the main affected zone through fine particle (PM1) to all the exercisers. IMPLICATIONS: Size-segregated particle concentrations in urban outdoors and within house premises were measured. The highest respiratory deposition doses (RDDs) were found for PM during morning hours in winter compared with remaining periods. During light exercise, the RDD values in alveolar (AL) region for PM10, PM2.5, and PM1 for male exercisers were significantly higher, 20.4%, 15.5%, and 15.4%, respectively, compared with female exercisers during morning peak hours in winter.

Rain pH estimation based on the particulate matter pollutants and wet deposition study.

In forecasting of rain pH, the changes caused by particulate matter (PM) are generally neglected. In regions of high PM concentration like Dhanbad, the role of PM in deciding the rain pH becomes important. Present work takes into account theoretical prediction of rain pH by two methods. First method considers only acid causing gases (ACG) like CO2, SO2 and NOx in pH estimation, whereas, second method additionally accounts for effect of PM (ACG-PM). In order to predict the rain pH, site specific deposited dust that represents local PM was studied experimentally for its impact on pH of neutral water. After incorporation of PM correction factor, it was found that, rain pH values estimated were more representative of the observed ones. Fractional bias (FB) for the ACG-PM method reduced to values of the order of 10(-2) from those with order of 10(-1) for the ACG method. The study confirms neutralization of rain acidity by PM. On account of this, rain pH was found in the slightly acidic to near neutral range, despite of the high sulfate flux found in rain water. Although, the safer range of rain pH blurs the severity of acid rain from the picture, yet huge flux of acidic and other ions get transferred to water bodies, soil and ultimately to the ground water system. Simple use of rain pH for rain water quality fails to address the issues of its increased ionic composition due to the interfering pollutants and thus undermines severity of pollutants transferred from air to rain water and then to water bodies and soil.

Development of emission factors for motorcycles and shared auto-rickshaws using real-world driving cycle for a typical Indian city.

Vehicular emission is one of the most important contributors of urban air pollution. To quantify the impact of traffic on urban air quality, it is necessary to quantify vehicular emission. In many cities of India, such as Dhanbad, shared auto-rickshaw is the pre-dominant mode of transportation. Indian Driving Cycle (IDC) and Modified Indian Driving Cycle (MIDC) are used for emission testing of motorcycles, shared auto-rickshaws and passenger cars in India for regulatory purposes. IDC used for motorcycles and shared auto-rickshaws does not recognize the difference in two vehicle classes in terms of driving pattern. In real world, shared auto-rickshaws, behave differently than motorcycles. To quantify the impact of shared auto-rickshaws on urban air quality accurately, emission factors (EFs) are required to derive from real-world driving cycles (DCs). In heterogeneous traffic, vehicles of one class affect the behavior of vehicles of other classes. To estimate the emissions from different vehicle classes accurately, EFs for motorcycles and passenger cars are also required to be revised. In this study, real-world DCs were developed for motorcycles, shared auto-rickshaws and passenger cars in Dhanbad. Developed DCs were used to calculate EFs for respective classes. Shared auto-rickshaws were found to have the highest deviation from EFs derived using IDC.