title: Indoor and outdoor suspended particulate matter and associated carbonaceous species at residential homes in northwestern Portugal.
abstract: Particulate matter with an aerodynamic diameter equal to or less than 10 μm (PM10), organic carbon (OC) and elemental carbon (EC) concentrations were measured simultaneously in the indoor and outdoor air of 4 residences located in urban and sub-urban areas in northwestern Portugal. The residences were studied with occupants. One residence was also studied without any indoor activity, taking advantage of the fact that the occupants had moved into a new home. First, 48-h aerosol samples were collected on quartz fiber filters with low-volume samplers equipped with size selective inlets. The filters were weighed and then analyzed for OC and EC using a thermal-optical transmittance method. The average indoor and outdoor PM10 concentrations in the occupied residences were 71.9 ± 38.3 μg/m(3) and 54.0 ± 13.3 μg/m(3), respectively. Despite the higher concentration of PM10 indoors, outdoor sources were found to be a significant contributor to indoor concentrations. An estimate based on data from the residence studied under different occupancy conditions indicated that outdoor sources can account for 68% of the indoor PM10 mass concentration. Average indoor to outdoor (I/O) ratios for OC ranged from 1.7 to 5.6 in occupied residences, showing that indoor sources, such as cooking, smoking, biomass burning and movement of people, strongly influenced indoor OC concentrations. In contrast, I/O ratios for EC were close to 1, except for a smokers' residence, suggesting that indoor concentrations were mainly controlled by outdoor sources, most likely from vehicular emissions and biomass burning.
authors.affiliation: Department of Environment & Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Danilo
authors.initials: D
authors.lastname: Custódio
authors.affiliation: Department of Environment & Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Pinho
authors.affiliation: Department of Environment & Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: cerqueira@ua.pt.
authors.forename: Mário
authors.initials: M
authors.lastname: Cerqueira
authors.affiliation: Department of Environment & Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Nunes
authors.affiliation: Department of Environment & Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Casimiro
authors.initials: C
authors.lastname: Pio
mesh_terms: D000336:Aerosols / Q000032:analysis; D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis* / Q000706:statistics & numerical data; D002244:Carbon / Q000032:analysis; D004784:Environmental Monitoring; D006798:Housing; D052638:Particulate Matter / Q000032:analysis*; D011174:Portugal; D001335:Vehicle Emissions / Q000032:analysis
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions; D002244:Carbon
keywords: Elemental carbon; I/O ratio; Indoor air; Organic carbon; PM(10)