Air quality assessment in passenger trains: the impact

Air Qual Atmos Health DOI 10.1007/s11869-015-0348-1

Air quality assessment in passenger trains: the impact of smokestack emissions T. Maggos 1 & D. Saraga 1 & K. Bairachtari 1 & I. Tzagkaroulaki 1 & S. Pateraki 1 & C. Vasilakos 1 & C. Makarounis 2 & A. Stavdaris 2 & G. Danias 2 & G. Anagnostopoulos 2 & V. Frountas 2

Received: 9 February 2015 / Accepted: 27 April 2015 # Springer Science+Business Media Dordrecht 2015

Abstract The influence of the smokestack emissions of a ground-level train in the air quality of the passenger carriages through the ventilation system was investigated in this work. To this end, a monitoring campaign was designed and implemented at 20 different in-train sites, e.g., conductor’s cabin, carriages with passenger seats, boarding carriages, spaces for disabled people, etc., during its journey between urban and rural areas. Measurements of inorganic (NOx, SO2, CO) and organic (benzene, polyaromatic hydrocarbons, total volatile organic compounds) compounds as well as airborne particulate matter (PM) in different size ranges (ΡΜ10, ΡΜ2.5, ΡΜ1) were carried out in the interior of the carriages of a diesel engine-powered train (type KAT 2000) during fixed round trips. An exhaust dispersion cone hook was used for intervention purposes leading to the reassessment of the in-train air quality at the most contaminated sites. In order to produce reliable and comparable data, targeted measurements were conducted in a railbus which was used as reference. Based on the analysis, the air pollutants and particle levels exhibit significant variations at the same sampling point during the train journey, possibly due to the route characteristics (tunnels, uphills, turns, speed). Significant spatial fluctuations in the same train depending on the position and the proximity to Electronic supplementary material The online version of this article (doi:10.1007/s11869-015-0348-1) contains supplementary material, which is available to authorized users. * T. Maggos [email protected] 1

Environmental Research Laboratory, INRASTES, National Center for Scientific Research BDEMOKRITOS^, Aghia Paraskevi Attikis 15310 Athens, Greece

2

Hellenic Railways Organization (OSE), Karolou 1-3, Athens, Greece

the smokestack plume and the ventilation system inlet were observed as well. It is worthy to note that decreased pollutant values were observed during the intervention. Keywords Train passenger cars . Indoor air quality . Smokestack emissions . Ventilation . Microenvironments

Introduction People tend to spend between 85 and 90 % of their time exposed to the indoor rather than the outdoor atmosphere (Chan et al. 2003a, 2003b) Apart from the indoor and outdoor house and working microenvironments (where a respectable number of measurements data bases exist), some other microenvironments such as transit microenvironments (e.g., inside private cars or means of public transport), in which people use to spend time during the day, gain the focus of the scientific interest on the subject of the indoor air quality. The characterization of these microenvironments contributes to assess the overall exposure of a person to a number of pollutants. Traveling or commuting by train has increased during the last decades in Europe and USA, as modern trains offer a rapid and usually an environmentally friendly way to travel (Leutwyler et al. 2002; Eurostat, passenger transport statistics). Thus, air quality in train transportation has become an increasing concern for the general public. Several types of indoor air problems can be encountered in a train coach: smoking, inadequate ventilation, bad segregation between smokers and non-smokers sections, reduced comfort because of overcrowding in the coaches, etc. (Roussel et al. 1994). However, data of air pollutant measurements inside trains are quite limited and especially for Europe, where very few papers have been published on the topic. Most of the

Air Qual Atmos Health

published works refer to underground railway systems (carriages and/or platforms), while a limited number of studies have been conducted inside ground-level trains. Chan et al. 2002 compared commuters’ exposure to particulate matter (PM)10 and PM2.5 in four different types of public transportation in Hong Kong. The particle levels appeared to be strongly influenced by both the mode of transport and its ventilation system, while the railway transport was linked to significant lower PM burden being compared with the one produced by buses, trams, taxis, and ferries. The results coincide well with those reported by Chan et al. 2003a for volatile organic compounds (VOCs) who indicated that the passengers’ exposure in China was clearly lower in the subway than in the roadway transports. On the contrary, Lau and Chan (2003) found higher VOC values in subway monitoring sites, and as they concluded, the origin of toluene, ethylbenzene, and xylenes (TEX) was the underground tunnel or the stations and not the train interior. The PM10 and PM2.5 exposure levels have been quantified inside trains on four routes and platforms, in Taipei, Taiwan (Cheng et al. 2008). As reported, particle concentration values inside trains were lower than those measured in station platforms. In the same study, the role of the outdoor ambient PM levels was examined and a strong influence to the subway system indoor levels was identified. The role of low air exchange due to the lack of mechanical ventilation system in the trains was investigated through another study conducted in the subway lines in Seoul, Korea (Park et al. 2008). The obtained PM10 and PM2.5 levels inside trains were higher than those measured on platforms and in ambient air. The high levels of CO2 measured in the subway emphasize the role of the low ventilation. The role of airconditioning systems in the passenger carriages of a railway transit system in Beijing was investigated by Li et al. (2007). The results showed that the in-train air quality in the (above) ground railway with air conditioning was more acceptable than those in the underground system. All of the above listed studies focused mainly on the connection between the indoor air quality with the train type, the passengers’ activity and comfort as well as the air renewal but did not investigate specifically the impact of smokestack emissions on the interior of the train cabins. The aim of the present study is to estimate the impact of the train’s smokestack emissions on the air quality of the passengers’ carriage interior through the ventilation system. For that purpose, target measurements of important air pollutants (inorganics, organics, and particulate matter) were conducted at 20 sites in the interior of a ground passenger train.

Experimental study design A diesel engine-powered train (type KAT 2000) consisting of two air-conditioned passenger carriages was allocated by the Hellenic Railway Organization for the purpose of the present study. Twenty in-train sites were selected and fully equipped with analytical instruments for the monitoring of air pollutants and particulate matter (PM). Samples were collected during a default round trip Athens–Thiva–Athens for each sampling site separately (Figure S1). The duration of each non-stop trip was approx 1.5 h, and the traveled distance was 162 Km, while no passengers were on the train during the measurements. KAT2000 is a two-car diesel multiple unit (DMU) that features two fuel exhaust smokestacks, each one positioned at the middle area on each car’s roof. In an attempt to produce comparable data, corresponding measurements were also conducted in passenger carriages of a railbus (reference train) during the same trip. Railbus is a three-car articulated DMU which consists of a short middle car (the power module of the DMU which also features a passageway for passengers) and two passenger end cars, both semi-mounted on the power module car. Therefore, railbus features one fuel exhaust smokestack, positioned on the roof of the power module car. The purpose of the above comparison was to check the Bpolluted^ diesel train against a Bclean^ diesel one. As described above, both trains are powered with diesel engines and both emit combustion gases from the smokestack. However, significant structural and insulation differences exist among them. The railbus consists of a separate power engine car which is completely independent from the passengers’ carriage. Furthermore, the passengers’ cabins are very well insulated as the windows are sealed and the doors closed tightly. In contrary, the power engines of the KAT2000 are located under the floor of the passengers’ carriage and the smokestacks are located between the carriages. The latter results to have more leakage of gaseous pollutants within the wagons which in addition are not insulated as good as the railbus. Beyond the technical and constructional differences of the two train types, the significant number of reported complaints of KAT2000 passengers for unpleasant exhaust odors and the lack of similar complaints for the railbus lead us to select those types of trains for the current study and more specifically the railbus as reference.

Field study design Field sampling and measurements were conducted during June and July 2010. The monitoring instrumentation included equipment for continuous monitoring of temperature (T°C), relative humidity (RH), carbon monoxide (CO), nitrogen oxides (NO, NO2), sulfur dioxide (SO2), total volatile organic compounds (TVOCs), PM1, PM2.5, and PM10 as well as

Air Qual Atmos Health Table 1

Characteristics of sampling sites

Site code

Route

Train type

Site characteristics

Position

1 2 3 4 5 6 6A 7 8 9 10 11 12 13 14 15 15A

Athens–Thiva Athens–Thiva Athens–Thiva Athens–Thiva Athens–Thiva Athens–Thiva Athens–Thiva Athens–Thiva Athens–Thiva Athens–Thiva Athens–Thiva Thiva–Athens Thiva–Athens Thiva–Athens Thiva–Athens Thiva–Athens Thiva–Athens

KAT2000 KAT2000 KAT2000 KAT2000 KAT2000 KAT2000 KAT2000 KAT2000 KAT2000 KAT2000 KAT2000 KAT2000 KAT2000 KAT2000 KAT2000 KAT2000 KAT2000

Driver’s cabin (front) Small passengers’ cabin Main passengers’ cabin Passengers’ boarding cabin Small passengers’ cabin Passengers’ cabin for disabled people Passengers’ cabin for disabled people Main passengers’ cabin Passengers’ boarding cabin Small passengers cabin Driver’s cabin (back) Driver’s cabin (front) Small passengers’ cabin Passengers’ boarding cabin Main passengers’ cabin Passengers’ cabin for disabled people Passengers’ cabin for disabled people

Railcar tail end Railcar tail end Railcar tail end Railcar tail end Railcar tail end Railcar tail end Railcar tail end Railcar tail end Railcar tail end Railcar tail end Railcar tail end Railcar head Railcar head Railcar head Railcar head Railcar head Railcar head

16 17 18

Thiva–Athens Thiva–Athens Thiva–Athens

KAT2000 KAT2000 KAT2000

Small passengers’ cabin Passengers’ boarding cabin Main passengers’ cabin

Railcar head Railcar head Railcar head

19 20 R1 R2

Thiva–Athens Thiva–Athens Athens–Thiva Thiva–Athens

KAT2000 KAT2000 Railbus Railbus

Small passengers’ cabin Driver’s cabin (back) Passengers’ cabin Passengers’ cabin

Railcar head Railcar head Railcar tail end Railcar head

equipment for the sampling and determination of benzene and polyaromatic hydrocarbons (PAHs). Twenty in-train sites were selected for monitoring, based on their location in the carriages and the direction of the smokestack emissions plume. During each sampling day, the Fig. 1 Diesel engine-powered train (KAT 2000)

Exhaust dispersion cone use

in-train pollutant levels were measured at two different sites: one on Athens–Thiva route (approx. 11:00–12:30) and the other one on Thiva–Athens route (aprox 13:00–14:30). The characteristics of each sampling site and the position and the route where the sampling was performed are given in Table 1.


Useful information for each survey trip such as sampling time, trip duration, outdoor field’s characteristics (uphill, tunnels), and weather conditions was recorded on logbooks. The absence of passengers in the fully equipped train during the monitoring campaign should be emphasized. Any interference in air quality from the passengers could lead to unreliable results regarding the influence of the trains’ smokestack emissions. Finally, after the above-described sampling period, an intervention at the train’s smokestack took place. In particular, an exhaust dispersion cone was coupled on the stack and consequently, exhausts plume’s height was increased by ∼0.5 m. Afterwards, the in-train monitoring was repeated at the sites which were found to be the most contaminated. Train ventilation system The experimental study was performed in train passengers’ cars with a total length of 23.6 m. The train was equipped with a ventilation system that allows a total air (outside and

Table 2

recirculated air) change rate of about 3.500 m3/h in service. The air enters the zone through lateral inlets located along the windows. This air is composed of 46 % of fresh outdoor air and 54 % of recycled air from the zone itself. The air leaves the zone by a unique outlet located close to the door at the end of the car. It should be mentioned that the chimney of the engine was located very close to the air-condition inlet (Fig. 1).

Materials and methods Inorganic compounds The inorganic compound (NOx, SO2, CO) measurements followed BS EN 14211:2005, BS EN 14212:2005, and EN 14626:2005 standard methods, respectively. The instrumentation used (NO x chimiluminescence analyzer AC32M Environment S.A., 43i SO2 analyzer THERMO S.A., 48i CO analyzer THERMO S.A.) is shown in Picture S1.

Average concentrations of inorganic pollutants (NO, NO2, SO2, and CO) ΝΟ2 [μg/m3]

ΝΟ [μg/m3] Sampling site Avg

Max

Min

STDV Avg

1 2 3 4 5 6 6A

1175 530 778 558 1148 1810 1529

1999 1791 1495 1228 3676 3303 3325

93.0 430 24.0 438 63.0 382 8.00 398 28.0 1081 249 880 21.0 878

7 8 9 10 11 12 13 14 15 15A 16 17 18 19 20 R1 R2

1031 664 768 1028 669 303 140 246 835 638 405 323 291 198 168 400 11.0

2520 50.0 1599 3.00 1676 64.0 3086 33.0 1614 86.0 809 4.00 279 3.00 553 0.00 1386 111 1119 61.0 745 60.0 548 15.0 520 71.0 681 24.0 269 54.0 1814 n.d 85.0 n.d

556 403 404 875 385 207 60.5 137 286 249 178 144 111 133 58.4 468 433

SO2 [μg/m3]

Max Min

STDV Avg

CO [μg/m3]

Max

Min STDV Avg

Max

Min

STDV

1496 893 1218 1172 1589 1717 1172

452 35.0 81.0 23.0 81.0 916 n.d

252 234 281 280 399 225 377

1183 1578 1346 1485 928 510 162 383 534 174 568 255 255 348 429 1311 n.d

70.0 116 174 116 104 93.0 0.00 70.0 81.0 n.d n.d n.d n.d n.d n.d n.d n.d

301 487 304 386 245 139 44.6 102 134 58.2 191 70.6 92.9 79.8 103 299 n.d

220 197 183 187 239 334 285

418 422 229 275 439 583 521

61.0 71.0 38.0 65.0 132 24.3 82.0 42.5 6.00 93.7 143 106 40.0 103

16.0 10.0 8.40 13.6 11.7 19.7 14.1

25.6 30.3 14.3 32.1 31.7 29.8 25.6

4.15 2.55 2.58 4.44 2.07 8.06 2.82

5.53 7.39 3.50 8.40 8.54 7.03 7.07

191 195 216 220 191 126 130 107 222 210 185 147 149 117 111 130 44.0

344 439 363 407 372 248 176 162 336 382 264 231 218 183 138 309 118

74.0 27.0 11.0 61.0 32.0 67.0 44.0 0.00 88.0 130 113 52.0 105 76.0 78.0 44.0 11.0

10.3 9.00 8.30 11.4 9.50 4.40 2.60 3.10 8.90 7.60 5.80 5.00 4.80 3.30 2.80 5.00 1.00

20.7 17.5 14.4 28.7 17.9 7.60 3.80 5.20 14.1 11.4 8.60 6.90 6.50 7.00 3.80 17.1 1.80

1.57 1.14 3.33 1.86 3.96 1.41 1.22 n.d 1.44 2.85 2.82 2.10 2.61 1.73 1.60 0.93 n.d

4.89 4.69 3.16 8.42 4.33 2.02 0.69 1.75 3.38 2.31 1.61 1.33 1.23 1.30 0.64 4.14 0.50

58.8 94.4 57.0 91.3 70.5 53.5 23.4 31.8 46.8 37.5 32.5 41.8 31.5 23.0 15.8 64.4 71.7

905 348 696 708 789 1299 708 568 835 696 789 383 244 58.0 186 267 23.0 197 35.0 81.0 23.0 35.0 336 n.d


Particulate matter Method for PM10 sampling and mass determination PM10 sampling and mass determination was conducted in accordance to ΕΝ 12341. For the purpose of the measurements, a low volume (2.3 m 3 /h) sampler DERENDA LVS3.1 was used (Picture S2a). Particles were collected on 47-mm pre-conditioned Tissue Quartz filters, which were protected in plastic holders before and after sampling. Particle mass concentrations were determined gravimetrically using an electronic microbalance (Mettler Toledo MX-5) with a resolution of 10−6 g, which was placed in a Bweighting room^. The expanded uncertainty of the analytical procedure was 12.7 % (95 % k=2). Method for PM1 and PM2.5 sampling and mass determination A portable aerosol spectrometer, Grimm 1.108, was used for PM1 and PM2.5 measurements (Picture S2b). This unit is based on the principle of light scattering and gives the size

Table 3 Average concentrations for benzene, benzo[a]pyrene and TVOC

distribution of dust particles in number of particlesper liter in the range of 0.3–20 μm. In case of mass mode measurements (in μg/m3; range 0.23–20 μm), data are converted mathematically to PM10, PM2.5, and PM1 assuming similar scattering behavior, spherical particles, and constant density (measurement accuracy 5 %).

Organic compounds Benzene Sampling and analysis of benzene were performed according to EN 16017:2001. Samples were collected with the use of low-volume personal pumps (SKC model 222) and preconditioned glass tubes filled with Tenax TA (Gerstel) at flow rates of about 100 mL/min for 30 min (Picture S3). Samples were analyzed within 1 day after sampling, using a thermal desorption unit (Gerstel TDS3) coupled to a gas chromatograph (Agilent 6890 N), equipped with a flame ionization detector. LOD and LOQ for benzene analysis are 0.1 and 0.5 ng/L, respectively. The expanded uncertainty of the analytical procedure was 11.7 % (95 % k=2).

Sampling site

Benzene (μg/m3)

Uexp (95 % k=2)

Benzo[a]pyrene (ng/m3)

Uexp (95 % k=2)

TVOC (mg/m3)

1 2 3 4 5 6 6A 7 8 9 10 11 12 13 14 15

1.0 1.2 1.7 2.3 1.0 1.9 1.5 1.1 1.7 1.9 1.2 1.0 0.4 0.7 1.1 1.6

0.12 0.15 0.20 0.27 0.12 0.23 0.17 0.13 0.19 0.22 0.14 0.11 0.05 0.09 0.13 0.18

0.09 0.08 0.10 0.05 0.05 0.06 0.09 0.08 0.04 0.08 0.44 0.07 0.03 0.04 0.04 0.02

0.02 0.01 0.02 0.01 0.01 0.01 0.02 0.01 0.01 0.01 0.07 0.01 0.01 0.00 0.01 0.00

0.4 0.5 0.3 1.1 0.6 0.9 0.3 0.8 1.0 0.8 1.1 0.9 0.9 0.7 0.5 0.6

15A 16 17 18 19 20 R1 R2

1.6 1.3 1.2 0.6 0.8 0.4 1.3 0.7

0.18 0.15 0.14 0.07 0.09 0.05 0.16 0.08

0.05 0.07 0.04 0.04 0.04 0.04 0.06 0.04

0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01

0.3 0.6 0.7 0.4 0.5 0.2 0.3 0.2


during the campaign were 24 °C and 45 %, respectively. The average value for air pressure—measured by a digital barometer—was 995 hPa.

Method for polyaromatic hydrocarbons sampling and determination For the determination of the benzo[a]pyrene (Β[a]P), the collected ΡΜ10 samples were analyzed in accordance to ΕΝ 15549:2008. The analysis was conducted using gas chromatography–mass spectrometry GC–MS Agilent 7890A–5975C (Saraga et.al 2010) (Picture S2c). The LOD for PAH (benzo[a]pyrene) analysis was 0.42 pg/m3 while the expanded uncertainty was 16.8 % (95 % k=2).

QA/QC Standard operating procedures (SOPs) based on ISO standards and/or manufacturer’s manuals were used. More specifically, field and lot blanks were used and analyzed for particles, benzene, and PAHs. The automated analyzers (TVOC, NOx, CO, SO2) were calibrated and checked before the sampling campaigns according to the manufacturers’ instructions and to the standard procedures (BS EN 14211:2005; BS EN 14212:2005; EN 14626:2005).

Total volatile organic compounds TVOC sampling and determination was conducted with the use of a portable air chromatographer Photovac Voyager with PID detector (Picture S4). The carrier gas was ultra zero air, H/C free. Isobutylene was used as the standard gas for the calibration of the instrument.

Results and discussion

Environmental parameters

Pollutant levels at different sampling sites/different carriage types

Temperature and relative humidity were measured using HOBO data loggers. The mean values inside the carriages

Tables 2, 3, and 4 summarize the relative results for the inorganic (NO, NO 2 , SO 2 , and CO) and organic

Table 4 Average concentrations for PM10, PM2.5, and PM1

Sampling site

PM10 (μg/m3)

Uexp (95 % k=2)

PM2.5 (μg/m3)

Uexp (95 % k=2)

PM1.0 (μg/m3)

Uexp (95 % k=2)

1 2 3 4 5 6 6A 7 8 9 10 11 12 13 14 15 15A

45.1 50.2 64.7 61.3 50.3 48.3 38.2 72.0 46.3 34.9 39.5 107 42.0 60.8 56.4 41.9 41.8

5.8 6.4 8.3 7.9 6.4 6.2 4.9 9.2 5.9 4.5 5.1 13.7 5.4 7.8 7.2 5.4 5.4

16.3 12.6 15.2 19.0 8.2 6.8 5.6 6.8 7.2 6.5 4.3 12.5 7.3 12.4 16.1 5.4 6.4

2.1 1.6 2.0 2.4 1.1 0.9 0.7 0.9 0.9 0.8 0.6 1.6 0.9 1.6 2.1 0.7 0.8

12.3 5.4 8.8 10.2 5.5 4.9 2.0 4.1 4.1 4.1 2.6 7.8 5.3 7.5 9.4 3.7 2.5

1.6 0.7 1.1 1.3 0.7 0.6 0.3 0.5 0.5 0.5 0.3 1.0 0.7 1.0 1.2 0.5 0.3

16 17 18 19 20 R1 R2

49.1 71.0 59.9 30.7 34.3 15.4 5.6

6.3 9.1 7.7 3.9 4.4 2.0 0.7

22.2 15.7 17.4 7.9 19.1 3.8 2.2

2.8 2.0 2.2 1.1 2.4 0.5 0.3

11.5 7.8 9.1 3.4 22.1 2.3 1.1

1.5 1.0 1.2 0.4 2.8 0.3 0.1


Fig. 2 NO concentration levels at 20 in-train sites

(benzene, benzo[a]pyrene, TVOC) components as well as the particles (PM10, PM2.5, PM1) measured at the 20 sampling sites in KAT2000. Sites 6A and 15A are the after-intervention cases, while R1 and R2 are the sites in railbus. Being situated at the railcar tail end, the sampling sites 1 to 10 were characterized by the most elevated values for the inorganic compounds. The maximum value was recorded at site 6. As it was expected, the dispersion of pollutants from the smokestack plume caused higher values at the vehicles’ tail end sites. Coinciding well with the previous observation, the average concentration of NO is presented in Fig. 2. After the intervention (mounting of exhaust dispersion cone on the diesel engine exhaust ducts), the air quality monitoring was repeated at the two sites where the highest values were recorded (6A, 15A). It is noticed, that after the intervention, a significant reduction was occurred for most of the Table 5

measured pollutants (∼25 % for ΝΟ, ∼10 % for ΝΟ2, ∼ 20 % for SO2, and ∼70 % for CO). The latter comprises a strong evidence of the smokestack emission’s influence in the pollutants’ levels inside the passengers’ carriage. Regarding the organic pollutants, peaks also generally noticed at the sampling sites situated at the passenger vehicles’ tail end. Maximum values of TVOC and Β[a]P were recorded at sampling site 10, while for benzene, the maximum concentration was obtained at sampling site 4. A significant reduction of >50 % is noticed for TVOC concentration at the two sites (6A, 15A) where the measurements were repeated after the exhaust dispersion cone was installed on the smokestack. In opposition, it seems that this intervention had no effect on the benzene and Β[a]P levels. For most of the sampling sites, the PM10, concentration values ranged between 30 and 72 μg/m3 (average 48.3± 19.2 μg/m3). However, the case of sampling site 11 where the concentration is significantly higher (107 μg/m 3 )

Air pollutant levels from similar studies

Study

Area

Type of train

CO (ppm)

TVOC (ppm)

Benzene (μg/m3)

ΡΜ10 (μg/m3)

ΡΜ2.5 (μg/m3)

ΡΜ1 (μg/m3)

Present study Chan et al. 2002 Chan et al. 2003a Chan et al. 2003b Cheng et al. 2008 Dor et al. 1995 Fernandez and Ashmore 1995 Flachsbart et al. 1987 Lau W.L. and Chan L.Y. 2003 Leutwyler et al. 2002 Li et al. 2006, 2007 Park et al. 2008 Hewetta and Bullock 2014

Greece Hong Kong Guangzhou, China Hong Kong Taipei, Taiwan Paris Mexico city Washington, USA Hong Kong Switzerland Beijing, China Seoul, Korea USA

Railway Railway Subway Ground railway/subway Ground railway/subway Subway Metro Railway Railway Railway Ground railway Ground railway/subway Locomotives

1.4

0.53

1.93

52 48

11 38

7

67 10–97 210–950

8–68

108–325 144

37 118

7.6 3.1 2 12–33.5 2.32–5.8 3.0–3.8 0.9–1.8 0.12

0.3

13.7 8.6

14.7

Air Qual Atmos Health 600

Fig. 3 NO2 variation during a trip where high values of inorganic pollutants were recorded (sampling site 6)

550 500 450

NO2 (µg/m 3)

400 350 300 250 200 150 100 50 0 10:48

11:02

11:16

11:31

11:45

12:00

12:14

12:28

Time

comprises an exception. PM10 levels at the sites R1 and R2 in the railbus are quite lower (5–15 μg/m3), as well. PM2.5 varied from 2 to 22 μg/m3 (average 10.6± 5.5 μg/m3). The maximum value was noticed for sampling site 16, while the reference sites R1 and R2 present the lowest concentration. A decrease of 20 % in the levels of the specific fraction was observed at sampling site 6A after the intervention; however, no similar effect was recorded for the sampling site 15A. Finally, PM1 ranged between 1 and 12 μg/m3 (average 6.3± 4.5 μg/m3), with the maxima corresponding to sites 1, 16, and 20 and the minimum values being recorded to reference sites R1 and R2. Concerning the reference train (railbus), inorganic pollutants average concentrations at site R1 (railbus tail end) were noticed to be higher than those at R2 but still lower compared to all the sites of KAT2000. In general, the measured concentrations of all pollutants varied in significantly lower values Fig. 4 SO2 variation during a trip where high values of inorganic pollutants were recorded (sampling site 6)

compared to those in KAT2000 for the same route and driving conditions, strengthening the aspect of the smokestack emission’s influence in KAT2000 passenger carriages’ air quality. Finally, Table 5 presents measured pollutant levels from similar published works found in the literature. Although comparison is insecure (different train types, different ventilation, traveling conditions etc.), pollutant levels measured in the specific campaign are similar or lower than those reported by other studies except for the study of Hewetta and Bullock 2014, where the mean values for CO and NO2 were slightly lower than in the current study. Pollutants’ level fluctuation Figures 3, 4, 5, and 6 present the variation of NO2, SO2, CO, PM1, and PM2.5 during a trip which was characterized by increased values of inorganic pollutants (sampling site 6, at railcars tail end). A noteworthy fluctuation was detected in all


Fig. 5 CO variation during a trip where high values of inorganic pollutants were recorded (sampling site 6)

1800 1600

3

CO (µg/m )

1400 1200 1000 800 600 400 200 0 10:48

11:02

11:16

11:31

11:45

12:00

12:14

12:28

Time

cases. A significant peak was exhibited almost simultaneously, at around 11:20 a.m., by all pollutants. At that time, as recorded in the logbook, the train entered and crossed a tunnel for ∼1 min. Especially for NO2, after 1 h, another—higher—peak was detected. The route’s characteristics (variation in train’s orientation, speed) along with the outdoor field’s morphology which affects the train’s driving attitude might be the explanation for the intense pollutants’ level fluctuation. The outdoor environment could possibly affect the in-train pollutant variations. However, it should be noticed that the route was designed in a way that the train traveled over rural areas without significant air pollutants variations. The latter was confirmed from the air pollution data obtained from the National Monitoring Station operating in

the surrounding area (Aliartos) (National Monitoring Station Network). More specifically, during the in-train sampling period, the ambient air pollutant levels were low, characterized by insignificant variation. (http://www.ypeka.gr/Default.aspx?tabid=495&language= el-GR). Pollutant levels compared to EU limit values The comparison between pollutant measured values (NO2 and PM10) and EU Air Quality Limits for outdoor air (due to the absence of legislation on transport air quality) is presented in Figs. 7 and 8. As shown, in some cases, the measured concentration exceeds the limit values. In particular, in KAT2000, ΝΟ2 hourly limit of 200 μg/m3 was exceeded or almost

25

Fig. 6 PM1 and PM2.5 variation during a trip (sampling site 6)

PM1.0 PM2.5

20

µg/m3

15

10

5

0 10:48

11:02

11:16

11:31

11:45

Time

12:00

12:14

12:28


Fig. 7 Comparison of NO2 concentration in the carriages with limit values

350

NO2 (µg/m 3)

300

EU hourly limit value 200µg/m3

250 200 150 100 50 0

1

2

3

4

5

6

6A

7

8

9 10 11 12 13 14 15 15A 16 17 18 19 20 R1 R8

Sampling site

Conclusions

reached at eight and seven sampling sites, respectively. SO2 and CO concentration varied in quite lower levels than the corresponding limits for the outdoor air. Regarding particles, exceedances of the PM10 limit value for outdoor air (50 μg/m 3) were observed at ten sampling sites in KAT2000 while measured concentration at seven other sites almost reached it. PM2.5 levels proved to be lower than the corresponding limit (25 μg/m 3 ). Finally, for the organic pollutants no exceedances were recorded. It should be noted, however, that the comparison of in-train measurements with the EU limit values is indicative. For example, the NO2 standard is an hourly limit than can be crossed 18 times/year; the PM10 standard is a daily standard that can be crossed 35 times/year.

It is the purpose of the current study to investigate the effect of the train smokestack emissions in passengers’ carriage air quality through the ventilation system. An extended monitoring campaign was conducted in 20 sites in the train passengers’ car. Results show that the train’s exhaust plume enriched the passenger’s car with air pollutants through the ventilation system. The European limit values for outdoor air are exceeded for ΝΟ2 and ΡΜ10 at 8 and 10 sites in KAT2000, respectively. No exceedances of the limits established for working environment were recorded for any measured pollutant. In order to eliminate the influence of the exhaust plume in the carriages environment, an intervention of using an exhaust

120

Fig. 8 Comparison of PM10 concentration in the carriages with limit values

110 100 80

EU limit value 50µg/m3

3

ΡΜ10 (µg/m )

90 70 60 50 40 30 20 10 0

1

2

3

4

5

6

6A

7

8

9

10 11 12 13 14 15 15A 16 17 18 19 20 R1 R8

Sampling site


dispersion cone took place. The latter resulted in significant pollutants’ reduction which ranged between 10 and 70 %. However, in the case of NO2, despite the result of intervention (reduction of 20 %), the measured concentration momentarily exceeds the EU limit for outdoor air. Air pollutants and particle levels present significant fluctuation at the same site during the train’s journey. This can be attributed to the changes of the train’s route, e.g., uphill route can cause increase in engine speed with subsequent more intense engine emissions. All pollutants concentrations in the reference train (Railbus) were considerably lower being compared to those in KAT2000, indicating the significant influence of smokestack emissions in the air quality of KAT2000 passengers’ cars. Significant variation of the pollutants’ levels was also observed among the sampling sites in the same carriage depending on the position and the proximity to the smokestack and the ventilation system inlet. Compliance with ethical standards The manuscript is in compliance with the BAir Quality Atmosphere & Health^ journal ethical standards. Conflict of interest The authors declare that they have no conflict of interest.

References BS EN 14211:2005: Standard method for the measurement of the concentration of nitrogen dioxide and nitrogen monoxide by chemiluminescence BS EN 14212:2005: Standard method for the measurement of the concentration of sulphur dioxide by ultraviolet fluorescence Chan LY, Lau WL, Lee SC, Chan CY (2002) Commuter exposure to PM in public transportation modes in Hong Kong. Atmos Environ 36: 3363–3373 Chan LY, Lau WL, Wang XM, Tang JH (2003a) Preliminary measurements of aromatic VOCs in public transportation modes in Guangzhou, China. Environ Int 29:429–435 Chan LY, Lau WL, Zou SC, Cao ZX, Lai SC (2003b) Exposure level of carbon monoxide and respirable suspended particulate in public transportation modes while commuting in urban area of Guangzhou, China. Atmos Environ 36:5831–5840

Cheng Y-H, Lin Y-L, Liu C-C (2008) Levels of PM10 and PM2.5 in train rapid transit system. Atmos Environ 42:7242–7249 Dor F, Le MY, Festy B (1995) Exposure of city residents to carbon monoxide and monocyclic aromatic hydrocarbons during commuting trips in the Paris Metropolitan area. J Air Waste Manage Assoc 45:103–110 EN 14626:2005 Standard method for the measurement of the concentration of carbon monoxide by non-dispersive infrared spectroscopy ΕΝ 15549:2008 Air quality. Standard method for the measurement of the concentration of benzo(a)pyrene in ambient air EN 16017:2001 Indoor, ambient and workplace air. Sampling and analysis of volatile organic compounds by sorbent tube/thermal desorption/capillary gas chromatography. Pumped sampling Eurostat, Passenger transport statistics: http://ec.europa.eu/eurostat/ statistics-explained/index.php/Passenger_transport_statistics Fernandez AA, Ashmore MR (1995) Exposure of commuters to carbon monoxide in Mexico City II. Comparison of invehicle and fixed-site concentrations. J Expo Anal Environ Epidemiol 5:497–510 Flachsbart PG, Mack GA, Howes JE, Rodes CE (1987) Carbon monoxide exposures of Washington commuters. J Air Pollut Control Assoc 37:135–142 Hewetta P, Bullock W (2014) Rating locomotive crew diesel emission exposure profiles using statistics and Bayesian decision analysis. J Occup Environ Hyg 11(10):645–657 Lau W-L, Chan L-Y (2003) Commuter exposure to aromatic VOCs in public transportation modes in Hong Kong. Sci Total Environ 308: 143–155 Leutwyler M, Siegmann K, Monn C (2002) Suspended particulate matter in railway coaches. Atmos Environ 36:1–7 Li TT, Bai YH, Liu ZR, Liu JF, Zhang GS, Li JL (2006) Air quality in passenger cars of the ground railway transit system in Beijing, China. Sci Total Environ 367:89–95 Li T, Bai YH, Liu JF, Li JL (2007) In train air quality assessment of the railway transit system in Beijing: a note. Trans Res Part D 12:64–67 National Monitoring Station network webpage: (http://www.ypeka.gr/ Default.aspx?tabid=495&language=el-GR) Park D-U, Ha K-C (2008) Characteristics of PM10, PM2.5, CO2, CO monitored in interiors and platforms of subway train in Seoul, Korea. Environ Int 34:629–634 Roussel G, Roche D, Brahimi N, Lequang NT, Salem A, Ekindjian OG (1994) Quantification of passive smoking in a survey of smoker coaches in the French high-speed trains (TGV). Presse Med 23(34):1559–1564 (in French) Saraga D, Maggos T, Sfetsos A, Tolis E, Andronopoulos S, Bartzis J, Vasilakos C (2010) PAHs sources contribution to the air quality of an office environment: experimental results and receptor model (PMF) application. J Air Qual Atmos Health 3(4):225