Size Distributions of Polycyclic Aromatic Hydrocarbons and Elemental Carbon. 1. Sampling, Measurement Methods, and Source Characterization

Atmospheric polycyclic aromatic hydrocarbons in Mumbai, India

“…The impactor was connected to a continuous duty, carbon-vane vacuum pump and a constant air #ow rate of 28.8 lpm was maintained with an in-line rotameter. Low-volume impactor sampling was preferred to minimize volatilization losses of semi-volatile PAH species (Venkataraman et al, 1994b) which occur during hi-volume PM-10 sampling on glass "ber "lters (Coutant et al, 1988). Impactors have near 100% collection e$ciency for compounds of vapor pressures lower than 10\ atm (Zhang and McMurry, 1991) which includes the PAH species reported here.…”

Calculated respiratory exposure to indoor size-fractioned polycyclic aromatic hydrocarbons in an urban environment

“…Particle samples were segregated in size fractions of >18, 10-18, 5.6-10, 3.2-5.6, 1.8-3.2, 1.0-1.8, 0.56-1, 0.32-0.56, 0.18-0.32, 0.10-0.18, 0.056-0.10, and b0.056 μm D p at an airflow rate of 30 L/min. Similar sizesegregated sampling methods have been used in previous studies (Allen et al, 1996;Kawanaka et al, 2009;Venkataraman et al, 1994). Overall, six sets of samples were collected, each for a 48-h period.…”

“…This explanation obviously is not applicable here. Because indoor particles in closed environments may undergo a longer period of aging than outdoor particles, indoor PAHs may tend to affiliate preferably with large particles (Venkataraman et al, 1994).…”

“…Although published concentrations of indoor airborne PAHs in urban areas (Li et al, 2005;Lv et al, 2009) can be used to evaluate levels of human exposure as previously done (Bai et al, 2009;Cheng et al, 2007;Liu et al, 2007), not all these PAHs will settle into the respiratory system or penetrate deep into human lungs, where the highest risks are expected. Quite a few studies found distribution of PAHs in air particles as a function of particle sizes (Kawanaka et al, 2009;Offenberg and Baker, 1999;Venkataraman et al, 1994). In addition, it is well established that PAHs in different sized particles have different inhalation efficiencies, and may deposit in different regions of the respiratory system (Kawanaka et al, 2009).…”

Measurements of semivolatile and particulate polycyclic aromatic hydrocarbons in a bus station and an urban tunnel in Salvador, Brazil

“…9 The particulate PAHs measured in urban air and in roadway tunnels have been found in the respirable size range. 6,[10][11][12][13] PAHs are regarded as priority pollutants by both the United States Environmental Protection Agency and the European Community. While no standard currently exists in Brazil for PAH concentrations in ambient air, the UK Government Expert Panel on Air Quality Standards is considering an air quality standard for benzo(a)pyrene of 0.25 ng m 23 .…”