Report Mitigation Measures
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LIFE13 ENV/ES/000263 PM contributors and potential mitigation measures in the subway environment March 2017 IMPROVE LIFE13 ENV/ES/000263 Coordinated by PM contributors and potential mitigation measures in the subway environment 1 PM contributors and potential mitigation measures in the subway environment 2 PM CONTRIBUTORS AND POTENTIAL MITIGATION MEASURES IN THE SUBWAY ENVIRONMENT INDEX 1. INTRODUCTION ............................................................................................................... 5 2. METHODOLOGY ............................................................................................................... 6 2.1. SAMPLING CAMPAIGNS SCHEDULE ......................................................................................... 6 2.2. SAMPLING CAMPAIGNS PROTOCOL......................................................................................... 8 2.3. RAILTRACK RENEWAL ACTIVITIES............................................................................................ 9 2.4. VENTILATION SETTINGS ...................................................................................................... 12 2.5. PLATFORM AIR PURIFIERS ................................................................................................... 13 2.6. BRAKE EMISSIONS ............................................................................................................. 14 2.7. CHEMICAL ANALYSES ......................................................................................................... 14 3. RESULTS .......................................................................................................................... 16 3.1. PM2.5 CONCENTRATIONS .................................................................................................... 16 SAGRERA ............................................................................................................................... 16 SANTA COLOMA AND JOANIC .................................................................................................... 22 PALAU REIAL AND MARIA CRISTINA ........................................................................................... 31 POBLE SEC ............................................................................................................................. 37 TARRAGONA .......................................................................................................................... 42 COLLBLANC ............................................................................................................................ 47 TARRAGONA/PALAU REIAL (AIR PURIFIERS) ................................................................................. 52 MEASUREMENTS INSIDE TRAINS AND THE EFFECT OF AIR CONDITIONING. .......................................... 57 BRAKE EMISSIONS ................................................................................................................... 58 SUMMARY ........................................................................................................................... 59 3.2. CHEMICAL COMPOSITION OF AIRBORNE PARTICLES IN THE SUBWAY ............................................... 60 CHEMISTRY OF SUBWAY COMPONENTS ....................................................................................... 60 CHEMISTRY OF AMBIENT AIR IN DIFFERENT SUBWAY LINES .............................................................. 66 3.3. ACTIVITIES AFFECTING PM2.5 CHEMICAL COMPOSITION IN SUBWAY PLATFORMS ............................... 75 SAGRERA ............................................................................................................................... 75 SANTA COLOMA ..................................................................................................................... 81 JOANIC .................................................................................................................................. 84 PALAU REIAL AND MARIA CRISTINA ........................................................................................... 87 POBLE SEC ............................................................................................................................. 91 TARRAGONA .......................................................................................................................... 94 COLLBLANC ............................................................................................................................ 97 AIR PURIFIERS IN TARRAGONA AND PALAU REIAL ....................................................................... 100 PM contributors and potential mitigation measures in the subway environment 3 4. CONCLUSIONS ............................................................................................................... 107 5. REFERENCES .................................................................................................................. 112 PM contributors and potential mitigation measures in the subway environment 4 1. INTRODUCTION Ambient particulate matter (PM) present in the subway environment can originate from different sources and processes, producing a complex mixture of inhalable aerosols that is driven through the underground network on air currents induced by train movement and ventilation systems. Much of this "subway PM" is generated by mechanical wear and friction processes at the rail- wheel-brake and catenary-pantograph interfaces. However other sources can be important, such as the dust contribution arising from night tunnel maintenance work, and by the infiltration below ground of outdoor traffic-contaminated city air. An important objective of the measurement campaigns designed under the IMPROVE LIFE sampling program has been to focus on the different contributors to the mixed airborne materials present underground. Not only has the project investigated how PM concentrations on platforms and in trains are influenced by train “piston effects”, forced ventilation systems, and transient “pollution events” induced by maintenance work, but it has accumulated a huge database of over 500 chemical analyses of ambient PM and source materials (such as brakes). Such information offers an opportunity for an improved understanding of the various origins of the continuously resuspended PM circulating underground, and facilitates the next logical step in this subway air quality study, namely the development of realistic PM mitigation strategies in underground train systems that will result in cleaner air being breathed by commuters. In this report, therefore, we focus on what the results from the IMPROVE LIFE sampling campaigns can teach us about the various PM contributors to particulates breathed underground, and how this information can help preparing the ground for the development of protocols aimed at PM mitigation and subway air quality improvement. PM contributors and potential mitigation measures in the subway environment 5 2. METHODOLOGY 2.1. Sampling campaigns schedule Sampling campaigns were carried out at different metro stations belonging to four subway lines between January 2015 and November 2016 (Figure 1). These campaigns were designed to specifically investigate the various influences on PM concentrations and compositions of night- work tunnel maintenance activities, different ventilation protocols, the use of different train brake pad compositions, and the effect of air purifiers still in experimental development. Stations selected for study of the effect of tunnel night work on platform air quality 1. Sagrera (L5), a station with two tunnels, each with one rail track and separated by a middle platform. Air quality measurements were conducted from 20th January to 1st April 2015. 2. Santa Coloma (L1), a station with a wide tunnel with two rail tracks. Air quality measurements were conducted from 1st October to 3rd November 2015. 3. Joanic (L4), a station characterized by one wide tunnel with two rail tracks separated by a middle wall. Air quality measurements were conducted from 3rd November to 22nd December 2015. 4. Palau Reial and Maria Cristina (L3), stations characterized by one wide tunnel with two rail tracks separated by a middle wall. Measurements were performed from 1st April to 14th May and from 14th May to 10th June, respectively. 5. Poble Sec (L3), with the same design as Maria Cristina and Palau Reial (Table 1), was chosen for a sampling campaign from 14th September to 11th October 2016. Stations selected for study of experimentation with ventilation protocols 6. Tarragona station (L3), a station with a wide tunnel with two rail tracks. Two campaigns were carried out at this station, the first one took place from 10th June to 1st July 2015 (warmer period), and the second one from 29th February to 10th April 2016 (colder period). In both cases the period included one week under an air circulation flow reversed from that of the normal one. 7. Collblanc station (L9S) from 11th May to 11th July 2016. This platform belongs to the newest automatic metro line of the city (L9S), opened in February 2016 to connect the city centre with the airport. This deep station has one rail track only and the platform is fitted with screen doors. Ventilation in the new deep stations is stronger than in the older conventional lines. Measurements were carried out in the platform with and without tunnel ventilation on. 8. Tarragona, Maria Cristina and Palau Reial stations (L3) were also selected for testing the effect of air purifiers manufactured