Characterization of Personal Exposure to PM2.5, Ultrafine Particles with Indoor and Outdoor Measurements in Fresno California

摘要

Air pollution in Fresno California has been an important issue for decades. Personal exposure to multiple air pollutants in Fresno was characterized by field sampling study that measured air pollutants along with individual time-location data for proximity to traffic emission. During 2012-2013, PM2.5, ultrafine particles, ozone, and black carbon concentrations were measured using the real-time monitors and gravimetric monitors. Sampling locations were ambient and indoor on campus of California State University Fresno, and residences, and in-vehicle during commute. During the 3-week intensive measurements period in January and February of 2013, indoor, outdoor, and personal air were measured in comparison with ambient monitoring site on Campus. PM2.5 concentrations were measured using Dust Trak DRX 8533 and 8534. 24-hour PM2.5 mass concentrations were collected in indoor, outdoor, and personal air. Using CPC 3007, personal exposures to ultrafine particles were measured. The time-location data was mapped using GPS loggers. PM2.5 was dominantly higher in outdoor air compared to personal or indoor air during most of time. Exceptions were short peak time exposures that a person may encounter any type of combustion sources in confined indoors. Ultrafine particle concentrations were influenced by close proximity to combustion sources, such as gas stove, electric stove, boiling, grilling, hot water use, lit candles, and existence of smoker whether the cigarette light is on or not. Roadway traffic conditions and fleets traveling in front of the sampling vehicle influenced in-vehicle air quality immediately. Indoor ozone concentration measurements indicated that major contribution of ambient air to indoor air of University buildings those were built in 1950s. Time-location data recorded subject's location information accurately most of the time during sampling periods. The air pollution levels by location and time are being analyzed and will be compared with previous studies.