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Association of polycyclicaromatic hydrocarbons with particles in automobile exhaust
248
]Ftl ANNUAl ('()NFIRENC[ O1 I H I GAb:l:
SOME
PHYSICAL
AEROSOL
USED
PROPERTIES FOR
LUNG
OF
COBALT
RETENTION
OXIDE STUDIES
(J. A, F'ERRON. W. KREYI ING and B. t-]AIDtR
Geseltschaft ffir Strahlen- und Umweltforschung m b H Miinchen, lnstitut ffir Strahlenschutz. [)-8042 Neuherberg, West G e r m a n y Cobalt oxide aerosols traced with s ' C o are used to study aerosol retention in beagles (Kreyling et al., 1978). I irst a test is carried out on the solubility of heat degradated cobalt chloride CoCI: in three solutions: distillated water, distillated water with NaCI and with 0.5 n HCI. The results shows that no Co" + can be detected, if the salt is healed up to 700 or 850°C. The detection limit is 1.3 ppm cobalt This result is in agreement with results published by Barnes et al. (1976). The aerosol for five retention studies is generated with a spinning top aerosol generator and heat degradated at 900cC. During an experiment the aerosol is monitored by a small angle light spectrometer. Measurements with an aerosol centrifuge and a scanning electron microscope (SEM) showed, that in the first three experiments a bimodal aerosol distribution is produced. The larger particles are monodisperse. The smaller particles have a diameter less than 0.4,am. It turned out, that these particles are not satellites produced by the spinning top generatoi, but condensation aerosols. Using C o ( N O 3 b instead ofCoCI 2 no condensation particles are found and monodisperse aerosols with diameter 0.8 and 2.7 ,am are produced with a standard deviation of about 0.15. Measurements with the SEM show that the aerosol particles are nearly spherical although with a rough surface. No growth of the aerosol particles is found at high humidities in a sedimentation apparatus, whose walls can be wetted. The aerosol produced in each inhalation experiment is collected on a filter and tested for solubility. In the first two experiments a flou' through system is used. Here a solubility of less than 43o is found, if a membrane filter with pore size of 0.02 p m is used. In the last three experiments the sandwich method is used. Here solubilities between 10 and 50)~, are found. From the results it is concluded that no increase offiher clearance is found by increasing or frequently refreshing the test volume ; an asbestos filter in comparison with a membrane filter slows down the filter clearance dramatically, probably caused by phosphates on the filter : and the filter clearance is still smaller than the one measured in beagles REFERENCES Barnes, J. E. et al. (1976) Hlth Phys. 30, 409. Kreyling, W. et al. (1977) J. Aerosol Sci. 10, 220. See also Congress Report (1976) Association tot Aerosol Research, p.224.
ASSOCIATION HYDROCARBONS
OF
POLYCYCLICAROMATIC
WITH
PARTICLES
IN AUTOMOBILE
EXHAUST JAN INGWERSEN and PETER SUNN PEDERSEN Laboratory for Energetics, Technical University of DenmarK, Denmark [ORBEN NIELSEN a n d ELFINN LARSEN
Chemistry Department, Rise National Laboratory, Denmark and JES FI NGI:R Air Pollution Laboratory, National Agency of Environmental Protection, Denmark The trend to reduce lead additives to gasoline is likely to increase the content of aromatic hydrocarbons in order ~o maintain the knock resistance of the fuel. This m a y lead to increased emission of polycyclic aromatic hydrocarbons (PAH), some of which are considered to be carcinogenic. A Ford Escort engine was run in a laboratory set-up. The exhaust gas was diluted with filtered ambient air to simulate the natural cooling and dilution process. A fraction of the diluted exhaust was passed through a cyclone battery and a filter, which separated particles of diameters above and below 1 #m, respectively ; furthermore, in a fev, cases, vapour phase PAH was collected in freeze traps, mounted after the filter. The samples were analyzed with H P L C for 7 characteristic PAH : anthracene, fluoranthene, 1-methylanthracene, pyrene, benzo(a)anthracene, benz~ (a)pyrene, and benzo(ghi)perylene, More than 90~o of the mass of the heavier P A H ' s (i.e. benzo(a)pyrene) was found on particles with a diameter below I ,am ; apparently this association takes place outside of the combustion chamber, and the PAH is adsorbed ~o the particles' surface. PAH emissions varied with the air-fuel ratio in a manner similar to particulate matter as well as to unburned hydrocarbons showing high emission rates at both very rich and very lean mixtures. The engine load was found to have much influence on PAH emissions both under steady- and unsteady-state conditions. The significance of the fuel composition was investigated by means of a series of specially produced fuels all havin~ R O N = 97. Changes in lead concentration had only a slight effect, but an increase in aromatic content lead to an increase in all seven P A H measured. Generally the PAH increase was higher when the fuel contained higher aromates. It is estimated that 25~°oof the B(a)P in the exhaust originated directly from the fuel--the rest was formed as a consequence of the combustion. The research was performed under contract between The European Economic C o m m u n i t y and The l)ani,;i',, National Agency of Environmental Protection. No. 131 75-10 ENV.DK
]Ftl ANNUAl ('()NFIRENC[ O1 I H I GAb:l:
SOME
PHYSICAL
AEROSOL
USED
PROPERTIES FOR
LUNG
OF
COBALT
RETENTION
OXIDE STUDIES
(J. A, F'ERRON. W. KREYI ING and B. t-]AIDtR
Geseltschaft ffir Strahlen- und Umweltforschung m b H Miinchen, lnstitut ffir Strahlenschutz. [)-8042 Neuherberg, West G e r m a n y Cobalt oxide aerosols traced with s ' C o are used to study aerosol retention in beagles (Kreyling et al., 1978). I irst a test is carried out on the solubility of heat degradated cobalt chloride CoCI: in three solutions: distillated water, distillated water with NaCI and with 0.5 n HCI. The results shows that no Co" + can be detected, if the salt is healed up to 700 or 850°C. The detection limit is 1.3 ppm cobalt This result is in agreement with results published by Barnes et al. (1976). The aerosol for five retention studies is generated with a spinning top aerosol generator and heat degradated at 900cC. During an experiment the aerosol is monitored by a small angle light spectrometer. Measurements with an aerosol centrifuge and a scanning electron microscope (SEM) showed, that in the first three experiments a bimodal aerosol distribution is produced. The larger particles are monodisperse. The smaller particles have a diameter less than 0.4,am. It turned out, that these particles are not satellites produced by the spinning top generatoi, but condensation aerosols. Using C o ( N O 3 b instead ofCoCI 2 no condensation particles are found and monodisperse aerosols with diameter 0.8 and 2.7 ,am are produced with a standard deviation of about 0.15. Measurements with the SEM show that the aerosol particles are nearly spherical although with a rough surface. No growth of the aerosol particles is found at high humidities in a sedimentation apparatus, whose walls can be wetted. The aerosol produced in each inhalation experiment is collected on a filter and tested for solubility. In the first two experiments a flou' through system is used. Here a solubility of less than 43o is found, if a membrane filter with pore size of 0.02 p m is used. In the last three experiments the sandwich method is used. Here solubilities between 10 and 50)~, are found. From the results it is concluded that no increase offiher clearance is found by increasing or frequently refreshing the test volume ; an asbestos filter in comparison with a membrane filter slows down the filter clearance dramatically, probably caused by phosphates on the filter : and the filter clearance is still smaller than the one measured in beagles REFERENCES Barnes, J. E. et al. (1976) Hlth Phys. 30, 409. Kreyling, W. et al. (1977) J. Aerosol Sci. 10, 220. See also Congress Report (1976) Association tot Aerosol Research, p.224.
ASSOCIATION HYDROCARBONS
OF
POLYCYCLICAROMATIC
WITH
PARTICLES
IN AUTOMOBILE
EXHAUST JAN INGWERSEN and PETER SUNN PEDERSEN Laboratory for Energetics, Technical University of DenmarK, Denmark [ORBEN NIELSEN a n d ELFINN LARSEN
Chemistry Department, Rise National Laboratory, Denmark and JES FI NGI:R Air Pollution Laboratory, National Agency of Environmental Protection, Denmark The trend to reduce lead additives to gasoline is likely to increase the content of aromatic hydrocarbons in order ~o maintain the knock resistance of the fuel. This m a y lead to increased emission of polycyclic aromatic hydrocarbons (PAH), some of which are considered to be carcinogenic. A Ford Escort engine was run in a laboratory set-up. The exhaust gas was diluted with filtered ambient air to simulate the natural cooling and dilution process. A fraction of the diluted exhaust was passed through a cyclone battery and a filter, which separated particles of diameters above and below 1 #m, respectively ; furthermore, in a fev, cases, vapour phase PAH was collected in freeze traps, mounted after the filter. The samples were analyzed with H P L C for 7 characteristic PAH : anthracene, fluoranthene, 1-methylanthracene, pyrene, benzo(a)anthracene, benz~ (a)pyrene, and benzo(ghi)perylene, More than 90~o of the mass of the heavier P A H ' s (i.e. benzo(a)pyrene) was found on particles with a diameter below I ,am ; apparently this association takes place outside of the combustion chamber, and the PAH is adsorbed ~o the particles' surface. PAH emissions varied with the air-fuel ratio in a manner similar to particulate matter as well as to unburned hydrocarbons showing high emission rates at both very rich and very lean mixtures. The engine load was found to have much influence on PAH emissions both under steady- and unsteady-state conditions. The significance of the fuel composition was investigated by means of a series of specially produced fuels all havin~ R O N = 97. Changes in lead concentration had only a slight effect, but an increase in aromatic content lead to an increase in all seven P A H measured. Generally the PAH increase was higher when the fuel contained higher aromates. It is estimated that 25~°oof the B(a)P in the exhaust originated directly from the fuel--the rest was formed as a consequence of the combustion. The research was performed under contract between The European Economic C o m m u n i t y and The l)ani,;i',, National Agency of Environmental Protection. No. 131 75-10 ENV.DK