Temperature and indoor environments

Abstract

From the thermodynamic perspective, the term temperature is clearly defined for ideal physical systems: A unique temperature can be assigned to each black body via its radiation spectrum, and the temperature of an ideal gas is given by the velocity distribution of the molecules. While the indoor environment is not an ideal system, fundamental physical and chemical processes, such as diffusion, partitioning equilibria, and chemical reactions, are predictably temperature‐dependent. For example, the logarithm of reaction rate and equilibria constants are proportional to the reciprocal of the absolute temperature. It is therefore possible to have non‐linear, very steep changes in chemical phenomena over a relatively small temperature range. On the contrary, transport processes are more influenced by spatial temperature, momentum, and pressure gradients as well as by the density, porosity, and composition of indoor materials. Consequently, emergent phenomena, such as emission rates or dynamic air concentrations, can be the result of complex temperature‐dependent relationships that require a more empirical approach. Indoor environmental conditions are further influenced by the thermal comfort needs of occupants. Not only do occupants have to create thermal conditions that serve to maintain their core body temperature, which is usually accomplished by wearing appropriate clothing, but also the surroundings must be adapted so that they feel comfortable. This includes the interaction of the living space with the ambient environment, which can vary greatly by region and season. Design of houses, apartments, commercial buildings, and schools is generally utility and comfort driven, requiring an appropriate energy balance, sometimes considering ventilation but rarely including the impact of temperature on indoor contaminant levels. In our article, we start with a review of fundamental thermodynamic variables and discuss their influence on typical indoor processes. Then, we describe the heat balance of people in their thermal environment. An extensive literature study is devoted to the thermal conditions in buildings, the temperature‐dependent release of indoor pollutants from materials and their distribution in the various interior compartments as well as aspects of indoor chemistry. Finally, we assess the need to consider temperature holistically with regard to the changes to be expected as a result of global emergencies such as climate change.

Impact of Climate Change on Indoor Air Quality: A Review

“…The effect of temperature on VOC emissions is a widely discussed topic. Salthammer and Morrison [ 21 ] listed 36 articles, published between 1975 and 2021, on the temperature dependence of VOC emissions from different building materials. The review of the 36 articles covered various families of pollutants and compiled different methods to study the dependence of VOC emissions on indoor temperature.…”

“…Salthammer and Morrison [ 21 ] highlighted the effect of temperature on the reaction rates of some pollutants with oxidants. They provided eight examples of indoor gas-phase reactions between ozone and hydroxyl as oxidants and nitrogen monoxide (NO), NO 2 , limonene, α-pinene, and β-pinene, along with their first-order reaction rates at 25 °C and the percentages of variation of these rates when the temperature increased to 35 °C: the variation ranged from −5 to 30.6% for these eight reactions.…”

A holistic modeling framework for estimating the influence of climate change on indoor air quality

“…When assuming Arrhenius’ law, typical activation energies of organic compounds are in the range between 40 kJ/mol and 120 kJ/mol 102 . Salthammer and Morrison provide an overview of temperature‐dependent processes in the indoor environment 103 …”

“…102 Salthammer and Morrison provide an overview of temperaturedependent processes in the indoor environment. 103 Sink effects can also be very different depending on the substance and the environment. 104,105 With a constant emission rate and no or irreversible sink, the concentration-time profile of an organic compound follows a simple single exponential time law.…”

Quantifying the impact of relative humidity on human exposure to gas phase squalene ozonolysis products

“…6 Chemistry indoors is affected by conditions which can vary signicantly in many ways, including variations in temperature, RH, room size, indoor surfaces, occupancy, indoor activities, air exchange rates, ventilation strategies, light levels, outdoor pollutant levels that are transported indoors, and oxidant concentrations. [27][28][29][30] Due to the complexity of indoor environments, the fact that people spend most of their time indoors and the impact that indoor air can have on outdoor chemistry, 31 it is important to develop models to improve our understanding of indoor chemistry. Indoor chemistry models can be used to better understand current experimental measurements, extrapolate to different indoor conditions and uncover gaps in our current understanding of indoor chemistry.…”