IMPacts of Cooking and Cleaning on indoor Air quality: towards healthy BuiLdings for the futurE: IMPeCCABLE

It is estimated that in developed countries such as the UK, we spend about 90% of our time indoors, with a significant portion spent in our homes. As a result, much of our exposure to air pollutants happens in the home even if the pollutants are made outdoors (e.g. by cars) and find their way indoors through windows and doors. As climate change leads to an increased focus on energy efficiency measures, one consequence is that we are building our homes to be more airtight to prevent energy loss. So compared to previous generations, we are spending more time indoors within buildings that are becoming more airtight. Clearly, if we then undertake activities indoors that form air pollutants, we could be exposed to high concentrations of air pollutants that could be harmful to health.

Such activities indoors include cooking and cleaning. We know that cooking generates high concentrations of particulate matter, nitrogen oxides and carbon monoxide. The emission rates of pollutants vary widely and depend on the cooking method, and the oil and food types. For instance, concentrations of small particles have been shown to exceed acute health standards over several hours when frying meat. Such concentrations are a concern as we know that adverse health effects of the respiratory and cardiovascular systems can result from exposure to these particles. Cleaning is another regular activity indoors, with studies showing that bleach cleaning can impact indoor air quality. We also know that domestic cleaning staff have high rates of asthma, again suggesting that cleaning activities may cause adverse health effects in some individuals.

As houses continue to become increasingly airtight through energy efficiency measures, we may increase our exposure to indoor air pollution if sources such as cooking and cleaning dominate our exposure. We need to understand the sources and reactions of pollutants indoors, particularly as many studies show that secondary pollutants formed through chemical reactions indoors are more harmful to health than primary emissions: for instance, we know that the carcinogen formaldehyde is a reaction product of limonene oxidation, the latter species being a key component of many cleaning formulations.

Therefore, to understand the impact of indoor emissions and to develop appropriate mitigation measures this project will:

(i) investigate the emissions from different pollution sources indoors, both in terms of the strength of these emissions and their composition
(ii) investigate the chemistry that occurs indoors following these emissions - what are the key chemical reactions indoors and what are the harmful products formed?
(iii) identify the consequent implications for building occupants in terms of exposure to air pollution - can we identify behaviour that might lead to higher exposures indoors and identify how to reduce that exposure?
(iv) use this knowledge to make recommendations for future building design and use based on rigorous science.

Although measurements of cooking and cleaning emissions exist, they tend to focus on a few emission rates, rather than studying a wide range of emitted species and the chemistry that follows from the emissions. Measurements have been mostly made in the US, where building design and use differ considerably to the UK. This project will use a holistic approach with combined experiments and modelling studies over a range of spatial scales (starting with small chambers and increasing up to test-house size), to understand the resulting indoor air quality when we cook and clean indoors. Our study will then deliver rigorous recommendations for building design, management and use based on typical indoor activities. The involvement of a range of stakeholders - including representatives from architecture, building management (including catering and cleaning managers), the chemical industry and building regulations - will ensure the results are relevant.

Who will benefit

The impact from this proposal will be focused on several key groups: building regulators; building designers and managers; cleaning product manufacturers and most importantly, building users. Those who work in jobs involving cleaning and cooking activities also stand to benefit through the improved knowledge that will be gained from this research. Clearly, given we all live and work in buildings and spend the majority of our time indoors, there is potentially a very wide societal impact from our research. Furthermore, the most vulnerable in society (the young, the elderly and the sick) tend to spend even more of their time indoors than the estimated 90% average for developed countries, so the there is also a social welfare consideration.

What will the impacts be?

All of the stakeholder groups will have a raised awareness of the need for effective ventilation when cooking and cleaning indoors. The specific impacts will vary by stakeholder group, so they are discussed separately:

Building regulators: building regulators play a key role in terms of setting the necessary parameters (e.g. ventilation rate) around the construction of new buildings. They are under increasing pressure to reduce energy loss in buildings given climate change concerns and this could potentially lead to worse IAQ if the impact of everyday activities in buildings is ignored. In quantifying the impacts of such activities on IAQ, we will provide the necessary evidence to support improved recommendations. This will lead to building regulations that better reflect the current building stock and lead to improved IAQ.

Building designers and managers: Our research will provide quantitative evidence on the impacts of cooking and cleaning indoors, through the measurements and complimentary modelling studies. This information will lead to improved design and management of buildings that are fit for purpose given typical indoor behaviour.

Cleaning product manufacturers: By understanding the pathways to pollutant formation following the use of cleaning products, we can make recommendations regarding the replacement of particularly reactive components, e.g. those that form high concentrations of formaldehyde through their ongoing chemistry. Such information will have impact for those who manufacturer such products, as it will provide relevant information for them to improve their products. Future sales could be enhanced if better product formulations are identified that are 'low emitters' and this claim is backed up by rigorous science

Building users: Many building users are currently unaware that they can take quite simple steps to improve IAQ. We will impart this information to them as described in the Pathways to Impact Section. For instance, although many houses have cooker hoods fitted in their kitchens, they are often not used during cooking activities. By quantifying the pollutants formed during cooking and putting them into context of other exposures (e.g. from vehicle exhausts whilst walking down a busy street), we will be able raise awareness of this issue and help improve air quality indoors and consequently, health and well-being through a reduced exposure to air pollutants.