How Do Breath and Skin Emissions Impact Indoor Air Chemistry?

TY - JOUR

T1 - How Do Breath and Skin Emissions Impact Indoor Air Chemistry?

AU - Kruza, Magdalena

AU - Carslaw, Nicola

N1 - © 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

PY - 2019/4/26

Y1 - 2019/4/26

N2 - People are an important source of pollution indoors, through activities such as cleaning, and also from “natural” emissions from breath and skin. This paper investigates natural emissions in high-occupancy environments. Model simulations are performed for a school classroom during a typical summer in a polluted urban area. The results show that classroom occupants have a significant impact on indoor ozone, which increases from ~9 to ~20 ppb when the pupils leave for lunch and decreases to ~14 ppb when they return. The concentrations of 4-OPA, formic acid, and acetic acid formed as oxidation products following skin emissions attained maximum concentrations of 0.8, 0.5, and 0.1 ppb, respectively, when pupils were present, increasing from near-zero concentrations in their absence. For acetone, methanol, and ethanol from breath emissions, maximum concentrations were ~22.3, 6.6, and 21.5 ppb, respectively, compared to 7.4, 2.1, and 16.9 ppb in their absence. A rate of production analysis showed that occupancy reduced oxidant concentrations, while enhancing formation of nitrated organic compounds, owing to the chemistry that follows from increased aldehyde production. Occupancy also changes the peroxy radical composition, with those formed through isoprene oxidation becoming relatively more important, which also has consequences for subsequent oxidant concentrations.

AB - People are an important source of pollution indoors, through activities such as cleaning, and also from “natural” emissions from breath and skin. This paper investigates natural emissions in high-occupancy environments. Model simulations are performed for a school classroom during a typical summer in a polluted urban area. The results show that classroom occupants have a significant impact on indoor ozone, which increases from ~9 to ~20 ppb when the pupils leave for lunch and decreases to ~14 ppb when they return. The concentrations of 4-OPA, formic acid, and acetic acid formed as oxidation products following skin emissions attained maximum concentrations of 0.8, 0.5, and 0.1 ppb, respectively, when pupils were present, increasing from near-zero concentrations in their absence. For acetone, methanol, and ethanol from breath emissions, maximum concentrations were ~22.3, 6.6, and 21.5 ppb, respectively, compared to 7.4, 2.1, and 16.9 ppb in their absence. A rate of production analysis showed that occupancy reduced oxidant concentrations, while enhancing formation of nitrated organic compounds, owing to the chemistry that follows from increased aldehyde production. Occupancy also changes the peroxy radical composition, with those formed through isoprene oxidation becoming relatively more important, which also has consequences for subsequent oxidant concentrations.

KW - detailed chemical model

KW - human emissions

KW - indoor air chemistry

KW - indoor air quality

KW - occupied indoor environments

UR - http://www.scopus.com/inward/record.url?scp=85061611444&partnerID=8YFLogxK

U2 - 10.1111/ina.12539

DO - 10.1111/ina.12539

M3 - Article

SN - 0905-6947

VL - 29

SP - 369

EP - 379

JO - Indoor air

JF - Indoor air

IS - 3

M1 - 10.1111/ina.12539

ER -