Road Dust Emission Due to Vehicular Traffic-A Review

Journal of Civil Engineering and Environmental Technology Print ISSN: 2349-8404; Online ISSN: 2349-879X; Volume 2, Number 3; January-March, 2015 pp. 257-260 © Krishi Sanskriti Publications http://www.krishisanskriti.org/jceet.html Road Dust Emission Due to Vehicular TrafficA Review Mr. Khalil Ahmad M. Bagwan1 and P.G. Sonavane2 1 M.Tech Student Civil Environment Engg. Civil Engineering Department Walchand College of Engineering, Sangli 2 Civil Engineering Department, Walchand College of Engineering, Sangli E-mail: [email protected], [email protected] Abstract—Dust generation on paved and unpaved roads is not much attended serious cause of air pollution. The presence of dust reduces visibility and poses an overall hazard to health and safety of road users. In India, it is customary to subject WBM road for traffic prior to its asphalting for some duration. During the maintenance of even asphalted roads, there is a practice to fill the pot holes by murum or similar locally available material. WBM surface and pot holes are major sources for dust emission. The emitted dust consists of range of particulate, majority of which remains suspended in the atmosphere. The abatement of respirable content is essential to protect human health as well as plant life. In India such efforts are not taken. In developed countries many researchers have contributed to study dust generation by vehicle on paved and unpaved road surface in spite of having better quality of roads as compared to Indian situation. Many efforts lead to develop relationship between nature of vehicle and dust emission. A few researchers have also deduced procedures to measure and characterize emitted dust on a real-time basis by involving high end instrumentation. In general the efforts are significant to minimize the ill effects of dust emission on plant, animal, and human life. It would be helpful to have review of the work done in developed countries and apply the results to improvise Indian road construction and maintenance practices. The study will also create many research avenues in the road construction industry in light of air pollution. and direction of the wind is a highly influential factor on its transportation [6]. The coarser fraction has local road safety, agricultural and environmental impacts on travellers and on residents near unpaved roads. The finer fraction can be transported more widely with potentially highly damaging impacts to health. The visible very coarse fraction that resettles on the road surface is then also subjected to grinding and regrinding by traffic to produce the fine particles. In India road maintenance is done by traditional methods. In this method bituminous roads are treated as WBM road and road damage like potholes, edge cracking etc. are recovered with the help of murum or locally available suitable material. Unpaved roads provide an almost inexhaustible supply of dust. The surface of unpaved roads is disturbed regularly so that dust particles are entrained into the air by every passing vehicle. The action of the vehicles wheels also pulverize the road material into ever decreasing particle sizes so that dust of all sizes is continually being produced, including the potentially dangerous PM10 and PM2.5 fractions [6]. India's road network is gigantic and has a total of about 4.6 million kilometers of roads out of which 2.1 million kilometers are surfaced roads and about 2.6 million kilometers of roads in India are the poorly constructed ones [7]. Roads indirectly contribute to the economic growth of the country. It is extremely essential that the roads are well laid out and strong but one of the striking underlying facts is the condition of the roads. India is home to several bad roads, be it the metropolitans, the cities or the villages. On the other hand traffic is one common problem in most of the cities. This is mainly because of industrialization and the sudden rise in vehicle ownership over the last few years. A vehicle travels on unpaved road, the force of the wheels on the road surface causes pulverization of surface material. Particles are lifted and dropped from the rolling wheels, and the road surface is exposed to strong air currents. The turbulent wake of the vehicle continues to act on the road surface after the vehicle has passed. On paved roads dust, which is often contaminated by fuel products and other pollutants are continually disturbed and made airborne. On unpaved roads, high volumes of surfacing material are available to be transported into the air as dust clouds and these may also contain other airborne pollutants. High vehicle speed is an important factor in generating dust due to the increased transfer of energy disturbing the dust from the surface of the road and the greater turbulence which transfers a greater amount of dust into the air. The amount of dust generated and its resettling on the road surface depends on various factors such as traffic speed, vehicle weight, local road conditions and rainfall. The strength Dust generation by vehicles on paved and unpaved roads can cause serious air pollution, reduce visibility and the safety of motorists, pedestrians and workers and pose an overall hazard 1. INTRODUCTION Mr. Khaalil Ahmad M. Bagwan B and P..G. Sonavane 258 to health. The abbatement of reespirable conteent is essentiall to prootect human heealth as well ass plant life. In India such effoorts aree not taken. Inn developed co ountries many researchers haave conntributed to stuudy dust generration by vehicle on paved and a unppaved road surrface in spite of o having betteer quality of roaads as compared to Indian situatiion. Therefore the aim of this t woork is to review w various worrks done by reesearchers for the abaatement of roaad dust emission essentially due to vehicuular traaffic. 2. REVIEW OF O PREVIOUS WORK DO ONE Maany researcherrs have contributed in this stuudy area over the woorld. For convvenience their work is dividded in following cattegories and itss review is takeen in forgoing paragraphs. 3. EXPERIME ENTAL ROA AD DUST ME EASUREMEN NT DEVICE A few f scientists have h attempted d to devise a suuitable device for expperimental roaad dust measurrement device [5]. In one of the stuudies an attem mpt has been made to deveelop a device to meeasure the dust production from the tesst sections forr a vehhicle on a reall-time basis. Th he device nam med as dustomeeter waas used, which is basically a moving m dust saampler, consistt of a standard highh volumetric sampler s with associated fillter meedia and accessories mounted d on the rear of o a pickup truuck (seee Fig. 1). The device is desiigned to allow for easy remooval andd replacement of the filter paaper. Trucck Filter Box B Roaad Surface This deevice consistss of the flexiible hose connnecting the suction pump to the fiilter (see Fig. 2). 2 During eachh test run the generatoor is started, and the truckk is driven at a stipulated speed. At A the beginninng of the 1-miile mark whenn the truck is movingg at the desireed speed, the pump is turneed on and a portion of the dust kiccked up by thee rear left tire is i drawn into the filteer. At the end of o the 1-mile run r the pump is i turned off, and the vehicle is thenn brought to a stop. The dustt laden filters were caarefully removved from the filter f box afteer every run, placed in i pre weighedd plastic bags, taken t to the labboratory, and weighedd. To demonstrrate the precisiion of the dustoometer as an experim mental road duust measuremeent device, niine replicate measureements were taaken on the 1--mile untreatedd test section at differrent speeds. Frrom this studyy they concludeed that there is lineaar relationship between the speed s and amoount of dust generatiion and approxximately 2.3 gm g of dust weere measured at a speeed of 20 milee/hr, and aboutt 7.3 gm were measured at 50 milee/hr. 4. DE ESIGN OF DUST D COLL LECTOR FO OR FOURWH HEELER A few scientists s have attempted to conduct the studdy on design of dust collector for foour- wheeler [11]. In this, workk is aimed to design a dust collector system for high cleaarance fourwheelerrs to minimizee the level of non-exhaust emissions e to some extent. This moodel consists a centrifugal fan f which is connectted to a 200W W motor which is connected to t battery of 12volt i.e. i car battery (see Fig. 3). This T battery runns our motor and hennce results in rotation r of mootor at 600rpm m, which turn the fan impeller at thhe same rpm. This rotation of impeller creates suction in thee nozzle attachhed to the cenntrifugal fan inlet oppening, this suuction in the hose or nozzlle would be enough for the dust too get sucked inn through the hose h and then passes through fan outlet o openingg. Then the fugitive f dust passing through the connecter c filterrs the air and deposits the dust in collector. This tank can stoore around 1.2kg of PM10 particles which is enoough for 500kkms, and then this storage c the tank needs to be cleanned by openingg the led and collecting p bag. dust in plastic Fig. 1 Sch hematic of Dusttometer attached to truck G Generator Connecting g hose Fig. 3: Deesign of Dust coollector system Fig. 2: Rear vieew of test truck k Journal of Civil C Engineering and Enviroonmental Technnology Print ISSN: 23 349-8404; Onliine ISSN: 23499-879X; Volum me 2, Number 3; January-Maarch, 2015 Rooad Dust Emisssion Due to Veehicular Trafficc-A Review 5. EFFECT OF O VEHICLE E CHARACT TERISTICS ON O UNPAVED ROAD DUST T EMISSIONS S A few f scientists have attempted d the study onn effect of vehiicle chaaracteristics onn unpaved road dust emisssions to measure em missions from vehicles and characterize their wakes and a injection height of dust plume [2]. For this a mix of civillian r of weighhts, andd military vehicles covering a substantial range lenngth and width dimensions, and a number of wheels w were used to understand how w these properrties relate to emissions e of duust, c V Vertical profile speecifically thee PM10 component. meeasurements off mass concen ntration of thee passing plum mes weere carried out using a seriess of three instrrumented toweers. Thhree towers weere set up colllinearly and perpendicular too a 1000m section of unpaved road d and all downnwind of the rooad at distances of 7, 50, and 100m m (see Fig. 4).. Each downw wind tow wer was instruumented with four DustTraaks configuredd to meeasure PM10 thhat were spaceed logarithmicaally in the vertiical dirrection. Figg. 4: Schematic diagram of thee 3-tower dust monitoring m systeem. Units are sho own in meters. Thhe DustTrak is a portable, batttery operated, laser-photomeeter thaat uses light scattering teechnology to determine mass m conncentration off dust in real--time. Five annemometers, one o winndvane, and one temperatture probe weere mounted on DuustTraks in order to charactterize the locaal meteorologiical connditions. Dust concentration n and meteorollogical data were w colllected and stoored on PCs lo ocated at each tower. Road dust d PM M10 emissions were created by having a test t vehicle traavel bacck and forth along a the road dway for a nuumber of passses. Affter passing of vehicle PM 10 0 emission fluxxes at each tow wer weere calculatedd from know wledge of thee vertical mass m conncentration proofile, the amb bient wind speed and directiion, andd the time thee plume took to pass the toowers. From this t stuudy, the emissiion factor is liinearly dependds upon on speeed andd vehicle weigght. Emission factors (EF = grams of PM M10 em mitted per veehicle kilomeetres travelledd) ranged frrom appproximately EF E = 0.8 × (k km/hr) for a light (1,200 kg) k passsenger car to EF = 48 × (km m /hr) for large military vehiccles 259 (18,0000 kg). This suggests thatt emissions are linearly dependeent on a vehicle’s v mom mentum. Othher physical characteeristics of thhe vehicles (ee.g., number of wheels, undercaarriage, area, height) did not appear a to heavvily influence the emiissions. The siize of a wake created by a vehicle was observeed to be dependdent on the size of the vehicle, increasing roughlyy linearly with vehicle v height.. 6. VE EHICLE-BASED METHO OD FOR ME EASURING RO OAD DUST EM MISSIONS A few scientists havve attempted to conduct thhe study on missions [4]. vehicle--based methodd for measuring road dust em TRAKE ER (Testing Re-entered R Aeerosol Kineticc Emissions from Roads) R which iss a vehicle-based method foor measuring road duust emissions. Particulate P mattter is sampledd in front and behind a vehicles tiree and the differrence in PM concentration c KER signal) is used u to infer thhe airborne fluxx of particles (TRAK from thhe roadway. Thhe concentratioon of airbornee particles is monitorred through inllets that are mounted m near thhe front tires of a vehhicle. These paarticle sensors are influencedd by the road dust geenerated from the contact off the tire with the road. A backgroound measureement of paarticle concenntrations is obtainedd simultaneouusly at a locatiion on the vehicle farther away frrom the tires. The T difference in the signals between the influencce monitors annd the backgroound monitor is related to the am mount of road dust generateed. From thiss study two indepenndent tests indiicated that the TRAKER signnal increases as the cube c of the speeed for a road dust d loading. Simultaneous S measureement of PM M10 dust emittted behind the t tires by TRAKE ER with PM100 flux measured using upwinnd/downwind towers suggested thatt the emissions factor for rooad dust was proportiional to the cube c root of the t TRAKER signal. The results also showed a linear relattionship betweeen distance based unpaved u road dust emissionn, PM10 emisssion factors, and vehhicle speed. 7. ESTIMATION OF ROAD D DUST US SING BIG SPRING NUMB BER EIGHT (B BSNE) A few scientists havve attempted to t device a procedure p to estimatee road dust usiing BSNEs [3]]. The sampler was used to measuree the dust em mitted by vehiccle. BSNE sam mpler has a relative large inlet arrea of 10 cm2. The measureements were carried out on two unppaved roads inn Lulea situatedd in Sweden. The carr used for duust generation is Ford Monddeo with an approxiimate weight of o 1730 kg andd 4 wheels. Thhe car drove for 15 runs with different d speedds. BSNE sam mplers were installedd at the heightts of 0.25 m, 0.50 0 m, 0.75 m and 1.00 m down wind w direction on o the road. Tw wo sets of BSN NE samplers were innstalled at the same s side of the t road in ordder to collect adequatte dust quantityy and the backkground dust was w assumed to be zeero. Besides thhe BSNE sampplers, two weaather stations were installed at the height h of 1 m annd 2 m. The measurements m were doone on the roaad sections whhich were perppendicular in the winnd direction to ensure the larrgest amount of o dust to be Journal of Civil C Engineering and Enviroonmental Technnology Print ISSN: 23 349-8404; Onliine ISSN: 23499-879X; Volum me 2, Number 3; January-Maarch, 2015 Mr. Khalil Ahmad M. Bagwan and P.G. Sonavane 260 obtained in the samplers. The dust in the samplers was collected by a brush with a great care to avoid sample loss. All the samples were weighed in the lab by a balance with the precision of 0.0001 g. The sample of surface material from the road was collected and tested for moisture content and particle size analysis. From this study it is concluded that the dust mass is highest at the lowest height and decreases with increasing height reaching zero at the top of the dust plume. It is reasonable to assume the zero dust mass to the ground surface level, which means the dust emission increasing sharply to the maximum value at a small height of near the surface. The dust mass collected in sampler is then divided by the inlet area of BSNE samplers to calculate the dust amount per square meter at the four measuring heights. It is also indicated that there is a strong relationship between vehicle speed and dust emission. Soil texture and the moisture content of the surface materials from the two roads were tested. The second road has a higher amount of fine grains with size below 63 μm than that of the first road. Soil texture is the most important soil factor influencing dust production. With finer fraction existing the more dust can be generated. REFERENCES [1] [2] [3] [4] [5] [6] [7] Chakraborty A., and Bansal A., “Design of dust collector for rear wheel of four-wheeler” International Journal of Emerging Technology and Advanced Engineering, 3, 7, July 2013, pp. 600-603. Gallies J.A., Etyemezian V., Kuhns H., Nikolic D. and Gillettec D.A., “Effect of vehicle characteristics on unpaved road dust emissions” Atmospheric Environment, 39, May 2005, pp. 2341-2347. Jia Q., Ansari N., Knutsson S., “Estimation of road dust using BSNEs” Natural Science, 5, May 2013, pp. 567-572. Kuhns H., George N, Dennis R. F. and Russell M., “TRAKER: A Method for Fast Assembly and Update of Paved and Unpaved Road Dust Emission Inventories” Atmospheric Environment, 42. Sanders G. T. and Addo Q. J., “Experimental road dust measurement device” Journal of Transportation Engineering, 126, 6, November/December 2000, pp. 530-535. Tony Greening (2011), “Quantifying the impacts of vehicle-generated dust: A comprehensive approach” The International Bank for Reconstruction and Development /The World Bank, 2011. World Bank Organization 2013, http://data.worldbank.org/indicator/IS.ROD.PAVE.ZS 8. DISCUSSION It can be seen from various contributions made in above mentioned paragraphs that, many researchers have identified the issues related with road dust emission in different ways. The major findings are as follows, the speed of vehicle and weight of vehicle are the major influencing factor for dust emission. Physical characteristics of the vehicles such as shape and number of tires and tread pattern may have minor influence on the emissions. The moisture content and the soil texture of the surface material is the most important soil factor influencing dust production. With finer fraction existing the more dust can be generated. In this context the study in relation with road dust emission is relevant. 9. CONCLUSION In India any of such works haven’t dealt with so far, the issue of road dust emission is handled by various researchers mostly at developed countries. Having absence of such studies for Indian conditions there is scope for the study. It would be helpful to have review of the work done in developed countries and apply the results to improvise Indian road construction and maintenance practices. The study will also create many research avenues in the road construction industry in light of air pollution. 10. ACKNOWLEDGEMENT This work was supported in part by a grant from Technical Education Quality Improvement Program (TEQIP-II). Journal of Civil Engineering and Environmental Technology Print ISSN: 2349-8404; Online ISSN: 2349-879X; Volume 2, Number 3; January-March, 2015