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- Beko, G., et al.
(författare)
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The Indoor Chemical Human Emissions and Reactivity (ICHEAR) project: Overview of experimental methodology and preliminary results
- 2020
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Ingår i: Indoor Air. - : Hindawi Limited. - 1600-0668 .- 0905-6947. ; 30:6, s. 1213-1228
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Tidskriftsartikel (refereegranskat)abstract
- With the gradual reduction of emissions from building products, emissions from human occupants become more dominant indoors. The impact of human emissions on indoor air quality is inadequately understood. The aim of the Indoor Chemical Human Emissions and Reactivity (ICHEAR) project was to examine the impact on indoor air chemistry of whole-body, exhaled, and dermally emitted human bioeffluents under different conditions comprising human factors (t-shirts/shorts vs long-sleeve shirts/pants; age: teenagers, young adults, and seniors) and a variety of environmental factors (moderate vs high air temperature; low vs high relative humidity; presence vs absence of ozone). A series of human subject experiments were performed in a well-controlled stainless steel climate chamber. State-of-the-art measurement technologies were used to quantify the volatile organic compounds emitted by humans and their total OH reactivity; ammonia, nanoparticle, fluorescent biological aerosol particle (FBAP), and microbial emissions; and skin surface chemistry. This paper presents the design of the project, its methodologies, and preliminary results, comparing identical measurements performed with five groups, each composed of 4 volunteers (2 males and 2 females). The volunteers wore identical laundered new clothes and were asked to use the same set of fragrance-free personal care products. They occupied the ozone-free (<2 ppb) chamber for 3 hours (morning) and then left for a 10-min lunch break. Ozone (target concentration in occupied chamber ~35 ppb) was introduced 10 minutes after the volunteers returned to the chamber, and the measurements continued for another 2.5 hours. Under a given ozone condition, relatively small differences were observed in the steady-state concentrations of geranyl acetone, 6MHO, and 4OPA between the five groups. Larger variability was observed for acetone and isoprene. The absence or presence of ozone significantly influenced the steady-state concentrations of acetone, geranyl acetone, 6MHO, and 4OPA. Results of replicate experiments demonstrate the robustness of the experiments. Higher repeatability was achieved for dermally emitted compounds and their reaction products than for constituents of exhaled breath.
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| 2. |
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| 3. |
- Zannoni, Nora, et al.
(författare)
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Effect of Ozone, Clothing, Temperature, and Humidity on the Total OH Reactivity Emitted from Humans
- 2021
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 55:20, s. 13614-13624
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Tidskriftsartikel (refereegranskat)abstract
- People influence indoor air chemistry through theirchemical emissions via breath and skin. Previous studies showed thatdirect measurement of total OH reactivity of human emissionsmatched that calculated from parallel measurements of volatile organiccompounds (VOCs) from breath, skin, and the whole body.In thisstudy, we determined, with direct measurements from twoindependent groups of four adult volunteers, the effect of indoortemperature and humidity, clothing coverage (amount of exposedskin), and indoor ozone concentration on the total OH reactivity ofgaseous human emissions.The results show that the measuredconcentrations of VOCs and ammonia adequately account for themeasured total OH reactivity. The total OH reactivity of humanemissions was primarily affected by ozone reactions with organic skinoilconstituents and increased with exposed skin surface, higher temperature, and higher humidity. Humans emitted a comparabletotal mixing ratio of VOCs and ammonia at elevated temperature-low humidity and elevated temperature-high humidity, withrelatively low diversity in chemical classes.In contrast, the total OH reactivity increased with higher temperature and higherhumidity, with a larger diversity in chemical classes compared to the total mixing ratio. Ozone present, carbonyl compounds were thedominant reactive compounds in all of the reported conditions.
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