Combining Chamber Experiments and Model Simulations to Evaluate an Indoor HONO Source with Surface Photochemical Properties

Nitrous acid (HONO) is an emerging indoor pollutant that can exert adverse health effects. The chemical production of indoor HONO has been attributed to NO2 heterogeneous reactions, and the source strength has been extensively evaluated via laboratory and model simulation studies. Photolysis of surf...

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Bibliographic Details
Published in:Indoor air 2023-10, Vol.2023, p.1-15
Main Authors: Wang, Youfeng, Zhang, Chong, Wang, Jianshu, Wang, Yaru, Zhang, Yingjie, Lin, Weili, Ye, Chunxiang
Format: Article
Language:English
Subjects:
Accumulation
Aerosols
Budgets
Catalysis
Chambers
Correlation analysis
Diel variations
Experiments
Health risks
Indoor air pollution
Indoor air quality
Indoor environments
Laboratories
Light
Nitrates
Nitrogen dioxide
Nitrous acid
Outdoor air quality
Photochemicals
Photolysis
Pollutants
Radiation
Simulation
Ventilation
VOCs
Volatile organic compounds
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Summary:Nitrous acid (HONO) is an emerging indoor pollutant that can exert adverse health effects. The chemical production of indoor HONO has been attributed to NO2 heterogeneous reactions, and the source strength has been extensively evaluated via laboratory and model simulation studies. Photolysis of surface nitrate has recently been proposed as an indoor HONO source based on correlation analysis between indoor HONO accumulation and visible light radiation. However, neither experimental validation of the proposed mechanism nor source strength characterization is currently available. In this work, we designed an outdoor photochemical chamber (OPC) to simulate indoor HONO accumulation and established an indoor photochemical model (ICM) to calculate the indoor HONO budget. Indoor HONO accumulation revealed a distinct diel variation with a daytime maximum. Only with this indoor HONO source, the ICM reproduced the indoor HONO budget determined in the OPC. The enhanced reactive cross section of surface nitrate in visible light accounted for the major portion of the HONO source budget (77.2%) and the distinct diel variation. Success with the ICM encouraged us to simulate the HONO budget in real indoor environments. The calculated HONO production rates from surface nitrate photolysis at noon ranged from 1.4 to 4.1 ppbv h-1 under different indoor scenarios. On a daily average, this indoor HONO source contributed 42.4–52.7% to the total chemical sources in the living room but only contributed 4.7% to that in the kitchen, where NO2 heterogeneous reactions dominated.
ISSN:0905-6947
1600-0668
DOI:10.1155/2023/3605937