scholarly journals Reactions among Indoor Pollutants

2001 ◽  
Vol 1 ◽  
pp. 443-457 ◽  
Author(s):  
Charles J. Weschler
Keyword(s):  
Atmospheric Chemistry ◽  
Ultrafine Particles ◽  
Analytical Techniques ◽  
Mouse Bioassay ◽  
Indoor Pollutants ◽  
Indoor Sources ◽  
Wood Coatings ◽  
Bioassay Procedure ◽  
Indoor Chemistry ◽  
Ventilation Rates

This paper reviews recent studies in the field of “indoor chemistry” — reactions among indoor pollutants. Advances have occurred in a number of areas. A mouse bioassay procedure has shown that ozone/terpene reactions produce products that are more irritating than their precursors, although the agents responsible for the deleterious effects remain to be determined. Indoor ozone/terpene reactions have been demonstrated to produce hydroxyl radicals, hydrogen peroxide, sub-micron particles, and ultrafine particles. New analytical techniques such as LC/MS and thermal desorption mass spectrometry have greatly improved our knowledge of the condensed-phase species associated with such particles. Indeed, the latter approach has identified a number of short-lived or thermally labile species, including organic hydroperoxides, peroxy-hemiacetals, and secondary ozonides, which would be missed by more conventional techniques. Investigators are making inroads into the poorly understood area of indoor heterogeneous chemistry. Systems studied include ozone/HVAC components, ozone/paint, and ozone/carpets. Another heterogeneous process that has been further examined is the indoor formation of nitrous acid through NO2/surface chemistry. Emissions from indoor sources that contribute to, or are altered by, indoor chemistry have also received attention. Researchers have expanded our awareness of reactive chemicals that can emanate from wood coatings and other products commonly used indoors. In a related vein, a number of recent investigations have shown that emissions from materials can be significantly altered by indoor chemistry. On the theoretical side, an outdoor atmospheric chemistry model has been modified for use as an indoor air model, the effects of ventilation rates on indoor chemistry have been simulated, and initial steps have been taken in applying computational fluid dynamics (CFD) methods to indoor chemistry.

scholarly journals Evaluation of the SOA Formation in the Reaction of Furfural with Atmospheric Oxidants

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 927
Author(s):  
Inmaculada Colmenar ◽  
Pilar Martín ◽  
Beatriz Cabañas ◽  
Sagrario Salgado ◽  
Florentina Villanueva ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ultrafine Particles ◽  
Analytical Techniques ◽  
Organic Aerosol ◽  
Nitrate Radical ◽  
Atmospheric Conditions ◽  
Severe Damage ◽  
Infrared Spectrophotometer ◽  
Cl Atoms ◽  
Product Study

An experimental product study of the reactions of furfural with the main tropospheric oxidants (Cl, OH and NO3) has been carried out using a Fourier Transform Infrared spectrophotometer (FTIR) and a gas chromatograph–mass spectrometer with a time of flight detector (GC–TOFMS). The main gas-phase products detected were 5-chloro-2(5H)-furanone, maleic anhydride, 2-nitrofuran and CO. Molar yields were quantified for the detected products in these reactions, thus suggesting the existence of nongaseous products that could not be observed with the analytical techniques employed. The formation of Secondary Organic Aerosol (SOA) from the oxidation of furfural with Cl atoms, OH, NO3 and ozone was investigated in a smog chamber in the absence of inorganic seed aerosols. The experimental results show the formation of ultrafine particles (less than 1 µm in diameter) for all of the studied reactions except for the nitrate radical. Given their small size, these ultrafine particles (<1 µm) can easily penetrate into the respiratory tract and reach the alveolar region. These particles, therefore, have the potential to cause severe damage to the respiratory system. The aerosol yield obtained, Y, was low (<0.04) in all cases, which means that the aerosols generated from furfural, under atmospheric conditions, could have little impact.

scholarly journals Decoding the social volatilome by tracking rapid context-dependent odour change

2020 ◽  
Vol 375 (1800) ◽  
pp. 20190259 ◽  
Author(s):  
S. Craig Roberts ◽  
Pawel K. Misztal ◽  
Ben Langford
Keyword(s):  
Social Context ◽  
Atmospheric Chemistry ◽  
Traditional Approach ◽  
Analytical Techniques ◽  
Ambient Air ◽  
Olfactory Communication ◽  
Multivariate Statistical ◽  
Flight Mass Spectrometry ◽  
Or Groups ◽  
External Stimuli

Odours can have a significant influence on the outcome of social interactions. However, we have yet to characterize the chemical signature of any specific social cue in human body odour, and we know little about how changes in social context influence odour chemistry. Here, we argue that adoption of emerging analytical techniques from other disciplines, such as atmospheric chemistry, might become game-changing tools in this endeavour. First, we describe the use of online chemical ionization time-of-flight mass spectrometry to sensitively measure many hundreds of gas-phase volatile organic compounds in real time. By analysing ambient air emanating from undisturbed individuals or groups, the technique enables a continuous recording of an instantaneous odour change in response to external stimuli and changing social context. This has considerable advantages over the traditional approach of periodic sampling for analysis by gas chromatography. We also discuss multivariate statistical approaches, such as positive matrix factorization, that can effectively sift through this complex datastream to identify linked groups of compounds that probably underpin functional chemosignals. In combination, these innovations offer new avenues for addressing outstanding questions concerning olfactory communication in humans and other species, as well as in related fields using odour, such as biometrics and disease diagnostics. This article is part of the Theo Murphy meeting issue ‘Olfactory communication in humans’.

scholarly journals Evaluation of Particulate Matter Pollution in Micro-Environments of Office Buildings—A Case Study of Delhi, India

2021 ◽  
Author(s):  
Saurabh Mendiratta ◽  
Sunil Gulia ◽  
Prachi Goyal ◽  
Sanjeev Kumar Goyal
Keyword(s):  
Particulate Matter ◽  
Ultrafine Particles ◽  
Work Performance ◽  
Indoor Air Pollution ◽  
Management Practices ◽  
Office Buildings ◽  
Indoor Environments ◽  
Air Pollution Control ◽  
Indoor Sources ◽  
High Level

High level of particulate matter in an office building is one of the prime concerns for occupant’s health and their work performance. The present study focuses on the evaluation of the distribution pattern of airborne particles in three office buildings in Delhi City. The study includes the Assessment of PM10, PM2.5 and PM1 in the different indoor environments, their particle size distribution, I/O ratio, a correlation between pollutants their sources and management practices. The features of buildings I, II, and III are old infrastructure, new modern infrastructure, and an old building with good maintenance. The results indicate that the average concentrations of PM10, PM2.5, and PM1 are found in the range of 55–150 μg m−3, 41–104 μg m−3 and 37–95 μg m−3, respectively in Building I, 33–136 μg m−3, 30–84 μg m−3 and 28–73 μg m−3, respectively in Building II and 216–330 μg m−3, 188–268 μg m−3 and 171–237 μg m−3, respectively in Building III. The maximum proportion of the total mass contributed by PM0.25–1.0 i.e., up to 75%, 86%, and 76% in the meeting room of Building I, II and III, respectively. The proportion of ultrafine particles was found higher in the office area where the movement was minimum and vice versa. The higher I/O indicates the contribution of the presence of indoor sources for ultra-fine and finer particles. Further, possible strategies for indoor air pollution control are also discussed.

scholarly journals Seasonal changes in snow surface roughness characteristics at Summit, Greenland: implications for snow and firn ventilation

2002 ◽  
Vol 35 ◽  
pp. 510-514 ◽  
Author(s):  
Mary R. Albert ◽  
Robert L. Hawley
Keyword(s):  
Surface Roughness ◽  
Atmospheric Chemistry ◽  
Ice Core ◽  
Chemical Species ◽  
Near Surface ◽  
Surface Snow ◽  
Diffusion Rates ◽  
Ventilation Rates ◽  
Diffusive Processes ◽  
High Winds

AbstractAir–snow transfer processes impact both ice-core interpretation and exchange affecting atmospheric chemistry. An understanding of seasonal differences in the character of the surface snow will facilitate evaluation of possible preferential seasonal exchange of reactive chemical species. Both diffusive processes and advective (ventilation) processes can serve to alter the physical, chemical and isotopic character of snow and firn. In this paper, we examine measurements of surface roughness over the course of a year at Summit, Greenland, and the implications for snow and firn ventilation. At Summit, during the winter-over experiment, summer and fall sastrugi amplitudes were approximately 5 cm and had smoothly curved profiles. the average amplitudes experienced mild increases in January, but by the end of February through March the amplitude increased to approximately 20 cm, and the profiles exhibited more abrupt geometries. Calculations are performed to show the potential impact of the changing roughness on interstitial ventilation rates in the snow, assuming that the permeability profile does not change in time. Under high winds, ventilation velocities in the near-surface snow can be up to 3 cms–1 in the winter, compared to 1 cms–1 in the summer. the frequency of 12 ms–1 winds in the summer, however, is less than in the winter. Under low-wind conditions, the summer roughness causes ventilation rates that are comparable to diffusion rates. However, in winter even 5 ms–1 wind conditions can cause the interstitial airflow due to ventilation to exceed the diffusion rates.

Photosensitization is in the air and impacts SOA generation and properties

2021 ◽  
Author(s):  
Christian George
Keyword(s):  
Chemical Composition ◽  
Atmospheric Aerosols ◽  
Atmospheric Chemistry ◽  
Organic Molecules ◽  
Transient Absorption ◽  
Waste Treatment ◽  
Chemical Interaction ◽  
Analytical Techniques ◽  
Transient Absorption Spectroscopy ◽  
The Impact

&lt;p&gt;Despite the importance of aerosols in atmospheric chemistry, climate and air pollution, our ability to assess the impact of aerosols on atmospheric physics and chemistry is still limited due to insufficient understanding of many processes associated with sources of particles, their chemical composition and morphology, and evolution of their composition and properties during their atmospheric lifetime. Indeed, atmospheric aerosols can be viewed as a complex conglomerate of thousands of chemical compounds forming a system that evolves in the atmosphere by chemical and dynamical processing including chemical interaction with oxidants.&lt;/p&gt;&lt;p&gt;Multiphase processes have also been shown to produce light absorbing compounds in the particle phase. The formation of such light absorbing species could induce new photochemical processes within the aerosol particles and/or at the gas/particle interface. A significant body of literature on photo-induced charge or energy transfer in organic molecules from other fields of science (biochemistry and water waste treatment) exists. Such organic molecules are aromatics, substituted carbonyls and/or nitrogen containing compounds &amp;#8211; all ubiquitous in tropospheric aerosols. Therefore, while aquatic photochemistry has recognized several of these processes that accelerate degradation of dissolved organic matter, only little is known about such processes in/on atmospheric particles.&lt;/p&gt;&lt;p&gt;This presentation will discuss photosensitization in the troposphere as having a significant role in SOA formation and ageing as studied by means of laser transient absorption spectroscopy, flow tube and simulation chamber experiments, all coupled to advanced analytical techniques. We will provide kinetic and mechanistic information on how photosensitization may introduce new chemical pathways, so far unconsidered, which can impact both the chemical composition of the atmosphere and might thus contribute to close the current SOA underestimation.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document