[Letter from Rachel W. Wade]

Personal exposure to nitrogen dioxide: relationship to indoor/outdoor air quality and activity patterns

“…The relationships between mean indoor and outdoor N02 concentrations observed in this study compare favorably with several previous investigations in demonstrating that there is a close association between the use of gas for cooking and elevated levels of N02 inside of homes and that the magnitude of departure from outdoor concentrations is greatest during the winter when both intentional ventilation and unintentional infiltration rates may be reduced, and stove use is likely to be increased (13)(14)(15)(16)18,51). Conversely, average indoor N02 concentrations in electric stove homes were below those measured outdoors.…”

“…Several recent reports have indicated that such exposure measurements fail to adequately assess individual exposure (2, 5, 7, 8-12). This inadequacy is acutely apparent for N02, since several reports have consistently shown that N02 concentrations consistently exhibit a declining gradient as one moves from kitchens with gas stoves to nonkitchen areas in these homes, to outdoor locations nearby, and then to kitchen and nonkitchen locations inside households that use electricity for cooking (13)(14)(15)(16)(17)(18). The importance of these departures from fixed station ambient air monitoring results is underscored by summaries of human activity pattern studies (29), indicating that on the average 90% of each day is spent indoors by employed men, while homemakers spent nearly 95% of their time indoors (2, [20][21][22][23].…”

“…Received for review June 4,1985. Revised manuscript received January 13,1986. Accepted February 18,1986. This study was supported primarily by a grant from Wisconsin Power and Light Co., Madison Gas and Electric Co., and Wisconsin Public Service Corp. and through cooperative agreement CR 808536010 between the Environmental Monitoring Systems Laboratory (EMSL) of the U.S. EPA and the Harvard School of Public Health.…”

Mathematical modeling of chemically reactive pollutants in indoor air

“…The deposition velocity for these species, which are believed to be removed at surfaces at the transport-limited rate, have been found to be 0.06-0.6 cm s'1, with the consensus value of 0.2 cm s'1 (33). The dif- 0.027" (aluminum), 0.015 (stainless steel), 0.036 (office), 0.061 (bedroom) 0.001-0.20 -0.0001 ± 0.001 0.0008 0.0017 ± 0.0014 0.0000-0.003 0.018 ± 0.009 0.011 0.006 (50% RH), 0.011 (60% RH), 0.017 (70% RH) 0.0003-0.12 0.005 ± 0.003 24 measurements in 13 buildings; one excluded due to suspected NO source (4) inferred from measurements of ozone loss rate in a single residence (12) for various materials exposed in a chamber study (12) inferred from measurements of ozone loss rate in experimental chambers and rooms (44) for various typical indoor materials exposed in a test room (45) decay rate in a house of emissions from gas-fired range; assumed A/V = 2 m'1 (46) decay rate in a house of emissions from gas-fired range; assumed A/V = 2 m_1 (47) analysis of data from gas-stove emissions experiment using simplified kinetic model; assumed A/V = 2 m"1 (9) for various indoor surface materials, measured in test chamber; 20-26 °C, 40-60% RH (48) concentration decay rate from gas-stove emission experiment in test room; 11 runs; includes homogeneous reactions; assumed A/V = 2 m"1 (5) decay rate in a house of emissions from gas-fired range; assumed A/V = 2 m"1 (47) analysis of decay rates from emissions due to gas-and kerosene-fired unvented heaters; attempt to exclude homogeneous reactions (6) for various indoor surface materials, measured in test chamber; 20-26 °C, 40-60% RH (48) analysis of concentration decay rate from gas-stove emission experiment in test room; 5 runs; includes homogeneous reactions; assumed A/V = 2 m"1 (5) "Data show strong positive correlation with relative humidity, varying from 0.0007 cm/s at 5% RH to 0.028 cm/s at 87% RH. fusion coefficient of these species is approximately 0.05 cm2 s'1, smaller than that for gaseous pollutants with lower molecular weights.…”

Μεταβατικη Κατασταση Λειτουργιας Οξειδωτικης Παγιδας Σωματιδιων Καυσαεριου Κινητηρων Diesel

“…Τεχνικές που στοχεύουν στην αύξηση της θερμοκρασίας (ενθαλπίας) του καυσαερίου. Στην κατηγορία αυτή εντάσσονται ο στραγγαλισμός της εισαγωγής του κινητήρα (HOWITT et al [24], LUDECKE et al [25], WADE et al [26]), η χρήση ηλεκτρικών αντιστάσεων στην είσοδο της παγίδας( LUDECKE et al [25]), η χρήση καυστήρα πετρελαίου με ή χωρίς παράκαμψη της ροής (WADE et al [26], URBAN et al [27], RAO et al [28], SIMON et al [29]), η χρήση μικροκυμάτων (GARNER et al [30]) και ο στραγγαλισμός της εξαγωγής του κινητήρα (PATTAS, STAMATELLOS, PATSATZIS, KIKIDIS, AIDARINIS, SAMARAS [31], STIGLIO et al [32]).…”