10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Carbonaceous Particles and Gaseous Compounds in Kitchens and Outdoor Air of Different Homes
CÉLIA ALVES, Ana Rita Oliveira, Teresa Nunes, Estela Vicente, Susana Marta Almeida, Mário Cerqueira, University of Aveiro
Abstract Number: 1149 Working Group: Indoor Aerosols
Abstract We spend most of our time in indoor environments. As building infrastructures are increasingly air tight to save energy, epidemiologic studies need to understand the extent to which outdoor levels of air pollutants remain a determinant of exposure and, therefore, of health in the indoor environment. Many of the outdoor pollutants are also some of the most common contributors to unhealthy air inside homes, due in part to a ubiquitous and possibly surprising activity: cooking. Moreover, kitchens started to become living spaces and, in most cases, are the hubs of the home.
A monitoring program involving 4 kitchens with different characteristics and the respective outdoor air was conducted in the region of Aveiro, Portugal, in October and November 2017. Low volume samplers were used to collect particulate matter (PM2.5) onto quartz filters, which were subsequently analyzed for their carbonaceous content (organic and elemental carbon, OC and EC) by a thermo-optical technique. Passive sampling of volatile organic compounds (VOCs) and carbonyls was also carried out.
Indoor and outdoor formaldehyde concentrations were 7.61±3.08 and 1.49±0.67 µg/m3, respectively, whilst the corresponding acetaldehyde levels were 7.94±4.63 and 0.41±0.36 µg/m3. Formaldehyde never exceeded the protection threshold of 100 µg/m3 imposed by the Portuguese legislation. The mean indoor VOC levels ranged as follows (µg/m3): benzene 0.92-2.9; ethylbenzene 0.80-1.7; toluene 3.9-9.3; m+p-xylene 2.4-5.8; o-xylene 1.0-2.2; styrene 0.27-1.5; 1,4-dichlorobenzene <0.10-1.2; trichloroethylene 0.35-2.5; tetrachloroethylene <0.10, and α-pinene 0.15-13.6. In general, all the kitchens except one registered indoor-to-outdoor VOC concentration ratios lower than one. The indoor levels of benzene, trichloroethylene, toluene, styrene and tetrachloroethylene were well below the thresholds laid down by the national regulations (5, 25, 250, 260 and 250 µg/m3, respectively). Xylenes, toluene and styrene were highly correlated with each other, both indoors and outdoors, suggesting common emission sources.
The mean indoor PM2.5 concentrations ranged from 13.8 µg/m3, in the kitchen located in a rural area, to 30.2 µg/m3 in a city center apartment with permanent occupancy. A mean outdoor level of 18.3 µg/m3 was obtained in the rural area, while very close mean values were recorded in the center and outskirts of the city (27.6-29.5 µg/m3). Total carbon (TC = OC + EC) accounted for about 30% of the PM2.5 mass in the kitchens of the rural area and city center apartment. In the kitchens of houses with less central location, but near roads with intense traffic, the TC/PM2.5 values were around 40%. The corresponding outdoor mass fractions ranged, in general, between 20 and 40%, the highest values being registered at the two locations more influenced by traffic. In general, the indoor OC/EC ratios were higher than the corresponding outdoor values. Regardless of location, ratios higher than 2 were usually observed. The highest OC/EC ratios were measured at the beginning of the sampling campaign, when the region was hit by wildfires.
Acknowledgements: Thanks are due for the financial support to CESAM (UID/AMB/50017 - POCI-01-0145-FEDER-007638), to FCT/MCTES through national funds (PIDDAC), and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. E. Vicente acknowledges the grant FRH/BD/117993/2016 from the Portuguese Foundation for Science and Technology.