Quantification of the impact of cooking processes on indoor concentrations of volatile organic species and primary and secondary organic aerosols

Indoor cooking and cleaning as a source of outdoor air pollution in urban environments

Indoor sources of air pollution, such as from cooking and cleaning, play a key role in indoor gas-phase chemistry. The focus of the impact of these activities on air quality tends to be indoors, with less attention given to the impact on air quality outside buildings. This study uses the INdoor CHEmical Model in Python (INCHEM-Py) and the Advanced Dispersion Modelling System (ADMS) to quantify the impact cooking and cleaning have on indoor and outdoor air quality for an idealised street of houses. INCHEM-Py has been developed to determine the concentrations of 106 indoor volatile organic compounds at the point they leave a building (defined as near-field concentrations). For a simulated 140 m long street with 10 equi-distant houses undertaking cooking and cleaning activities, the maximum downwind concentration of acetaldehyde increases from a background value of 0.1 ppb to 0.9 ppb post-cooking, whilst the maximum downwind chloroform concentrations increase from 1.2 to 6.2 ppt after cleaning. Although emissions to outdoors are higher when cooking and cleaning happen indoors, the contribution of these activities to total UK emissions of volatile organic compounds is low (less than 1%), and comprise about a quarter of those emitted from traffic across the UK. It is important to quantify these emissions, particularly as continued vehicle technology improvements lead to lower direct emissions outdoors, making indoor emissions relatively more important. Understanding how indoor pollution can affect outdoor environments, will allow better mitigation measures to be designed in the future that can take into account all sources of pollution that contribute to human exposure.

Lifestyle Changes and Industrialization in the Development of Allergic Diseases

PURPOSE OF REVIEW

Modernization and Westernization in industrialized and developing nations is associated with a substantial increase in chronic noncommunicable diseases. This transformation has far-reaching effects on lifestyles, impacting areas such as economics, politics, social life, and culture, all of which, in turn, have diverse influences on public health. Loss of contact with nature, alternations in the microbiota, processed food consumption, exposure to environmental pollutants including chemicals, increased stress and decreased physical activity jointly result in increases in the frequency of inflammatory disorders including allergies and many autoimmune and neuropsychiatric diseases. This review aims to investigate the relationship between Western lifestyle and inflammatory disorders.

RECENT FINDINGS

Several hypotheses have been put forth trying to explain the observed increases in these diseases, such as 'Hygiene Hypothesis', 'Old Friends', and 'Biodiversity and Dysbiosis'. The recently introduced 'Epithelial Barrier Theory' incorporates these former hypotheses and suggests that toxic substances in cleaning agents, laundry and dishwasher detergents, shampoos, toothpastes, as well as microplastic, packaged food and air pollution damage the epithelium of our skin, lungs and gastrointestinal system. Epithelial barrier disruption leads to decreased biodiversity of the microbiome and the development of opportunistic pathogen colonization, which upon interaction with the immune system, initiates local and systemic inflammation. Gaining a deeper comprehension of the interplay between the environment, microbiome and the immune system provides the data to assist with legally regulating the usage of toxic substances, to enable nontoxic alternatives and to mitigate these environmental challenges essential for fostering a harmonious and healthy global environment.

Understanding population exposure to size-segregated aerosol and associated trace elements during residential cooking in northeastern India: Implications for disease burden and health risk

Mass-size distribution of respirable aerosol and 13 associated trace elements (TEs) were investigated in rural kitchens using liquefied petroleum gas (LPG), firewood and mixed biomass fuels across three northeastern Indian states. The averaged PM10 (particulate matter with aerodynamic diameter ≤ 10 μm) and ΣTE concentrations were 403 and 30 μg m-3 for LPG, 2429 and 55 μg m-3 for firewood, and 1024 and 44 μg m-3 for mixed biomass-using kitchens. Mass-size distributions were tri-modal with peaks in the ultrafine (0.05-0.08 μm), accumulation (0.20-1.05 μm), and coarse (3.20-4.57 μm) modes. Respiratory deposition, estimated using the multiple path particle dosimetry model, ranged from 21 % to 58 % of the total concentration across fuel types and population age categories. Head, followed by pulmonary and tracheobronchial, was the most vulnerable deposition region, and children were the most susceptible age group. Inhalation risk assessment of TEs revealed significant non-carcinogenic as well as carcinogenic risk, especially for biomass fuel users. The potential years of life lost (PYLL) was the highest for chronic obstructive pulmonary disease (COPD: 15.9 ± 3.8 years) followed by lung cancer (10.3 ± 0.3 years) and pneumonia (10.1 ± 0.1 years), while the PYLL rate was also highest for COPD, with Cr(VI) being the major contributor. Overall, these findings reveal the significant health burden faced by the northeastern Indian population from indoor cooking using solid biomass fuels.

Indoor and outdoor air quality impacts of cooking and cleaning emissions from a commercial kitchen

Gas and particulate emissions from commercial kitchens are important contributors to urban air quality. Not only are these emissions important for occupational exposure of kitchen staff, but they can also be vented to outdoors, causing uncertain health and environmental impacts. In this study, we chemically speciated volatile organic compounds and measured particulate matter mass concentrations in a well-ventilated commercial kitchen for two weeks, including during typical cooking and cleaning operations. From cooking, we observed a complex mixture of volatile organic gases dominated by oxygenated compounds commonly associated with the thermal degradation of cooking oils. Gas-phase chemicals existed at concentrations 2-7 orders of magnitude lower than their exposure limits, due to the high ventilation in the room (mean air change rate of 28 h^-1 during operating hours). During evening kitchen cleaning, we observed an increase in the signal of chlorinated gases from 1.1-9.0 times their values during daytime cooking. Particulate matter mass loadings tripled at these times. While exposure to cooking emissions in this indoor environment was reduced effectively by the high ventilation rate, exposure to particulate matter and chlorinated gases was elevated during evening cleaning periods. This emphasizes the need for careful consideration of ventilation rates and methods in commercial kitchen environments during all hours of kitchen operation.

Temperature-dependent particle mass emission rate during heating of edible oils and their regression models

Particulate matter emitted by heated cooking oil is hazardous to human health. To develop effective mitigation strategies, it is critical to know the amount of the emitted particles. The purpose of this research is to estimate the temperature-dependent particle mass emission rates of edible oils and to develop models for source strength based on the multiple linear regression method. First, this study examined seven commonly used oils by heating experiments. The emission rates of PM2.5 and PM10 were measured, and the effects of parameters such as oil volume and surface area on the emission rates were also analysed. Following that, the starting smoke points (Ts') and aggravating smoke points (Tss') of tested oils were determined. The results showed that oils with lower smoke points had greater emission rates. Notably, the experiments performed observed that peanut, rice, rapeseed and olive oil generated PM2.5 much faster at 240 °C (2.22, 1.50, 0.82 and 0.80 mg/s, respectively, at the highest emission conditions) than that of sunflower, soybean, and corn oil (0.15, 0.12 and 0.11 mg/s, respectively). The temperature, volume, and surface area of oils all had a significant impact on the particle mass emission rate, with oil temperature being the most influential. The regression models obtained were statistically significant (P < 0.001), with the majority of R² values greater than 0.85. Using sunflower, soybean and corn oils, which have higher smoke points and lower emission rates, and smaller pans for cooking is therefore recommended based on our research findings.

Formation pathways of aldehydes from heated cooking oils

Cooking emissions account for a major fraction of urban volatile organic compounds and organic aerosol. Aldehyde species, in particular, are important exposure hazards in indoor residential and occupational environments, and precursors to particulate matter and ozone formation in outdoor air. Formation pathways of aldehydes from oils that lead to their emissions are not well understood. In this work, we investigate the underlying mechanisms involved in the formation of aldehydes from heated cooking oil emissions, through studying how antioxidants and oil composition modulate oxidation chemistry. Our results demonstrate that gaseous emissions are driven by radical-mediated autoxidation reactions in cooking oil, and the composition of cooking oils strongly influences the reaction mechanisms. Antioxidants have a dual effect on aldehyde emissions depending on the rates of radical propagation reactions. We propose a mechanistic framework that can be used to understand and predict cooking emissions under different cooking conditions. Our results highlight the need to understand the rates and mechanisms of autoxidation and other reactions in cooking oils in order to accurately predict the gas- and particle-phase emissions from food cooking in urban atmospheres.

Neurological susceptibility to environmental exposures: pathophysiological mechanisms in neurodegeneration and multiple chemical sensitivity

The World Health Organization lists air pollution as one of the top five risks for developing chronic non-communicable disease, joining tobacco use, harmful use of alcohol, unhealthy diets and physical inactivity. This review focuses on how host defense mechanisms against adverse airborne exposures relate to the probable interacting and overlapping pathophysiological features of neurodegeneration and multiple chemical sensitivity. Significant long-term airborne exposures can contribute to oxidative stress, systemic inflammation, transient receptor subfamily vanilloid 1 (TRPV1) and subfamily ankyrin 1 (TRPA1) upregulation and sensitization, with impacts on olfactory and trigeminal nerve function, and eventual loss of brain mass. The potential for neurologic dysfunction, including decreased cognition, chronic pain and central sensitization related to airborne contaminants, can be magnified by genetic polymorphisms that result in less effective detoxification. Onset of neurodegenerative disorders is subtle, with early loss of brain mass and loss of sense of smell. Onset of MCS may be gradual following long-term low dose airborne exposures, or acute following a recognizable exposure. Upregulation of chemosensitive TRPV1 and TRPA1 polymodal receptors has been observed in patients with neurodegeneration, and chemically sensitive individuals with asthma, migraine and MCS. In people with chemical sensitivity, these receptors are also sensitized, which is defined as a reduction in the threshold and an increase in the magnitude of a response to noxious stimulation. There is likely damage to the olfactory system in neurodegeneration and trigeminal nerve hypersensitivity in MCS, with different effects on olfactory processing. The associations of low vitamin D levels and protein kinase activity seen in neurodegeneration have not been studied in MCS. Table 2 presents a summary of neurodegeneration and MCS, comparing 16 distinctive genetic, pathophysiological and clinical features associated with air pollution exposures. There is significant overlap, suggesting potential comorbidity. Canadian Health Measures Survey data indicates an overlap between neurodegeneration and MCS (p < 0.05) that suggests comorbidity, but the extent of increased susceptibility to the other condition is not established. Nevertheless, the pathways to the development of these conditions likely involve TRPV1 and TRPA1 receptors, and so it is hypothesized that manifestation of neurodegeneration and/or MCS and possibly why there is divergence may be influenced by polymorphisms of these receptors, among other factors.

Real-time measurements of product compounds formed through the reaction of ozone with breath exhaled VOCs

Human presence can affect indoor air quality because of secondary organic compounds formed upon reactions between gaseous oxidant species, e.g., ozone (O₃), hydroxyl radicals (OH), and chemical compounds from skin, exhaled breath, hair and clothes. We assess the gas-phase product compounds generated by reactions of gaseous O₃ with volatile organic compounds (VOCs) from exhaled human breath by real time analysis using a high-resolution quadrupole-orbitrap mass spectrometer (HRMS) coupled to a secondary electrospray ionization (SESI) source. Based on the product compounds identified we propose a reaction mechanism initiated by O₃ oxidation of the most common breath constituents, isoprene, α-terpinene and ammonia (NH₃). The reaction of O₃ with isoprene and α-terpinene generates ketones and aldehydes such as 3,4-dihydroxy-2-butanone, methyl vinyl ketone, 3-carbonyl butyraldehyde, formaldehyde and toxic compounds such as 3-methyl furan. Formation of compounds with reduced nitrogen containing functional groups such as amines, imines and imides is highly plausible through NH₃ initiated cleavage of the C-O bond. The detected gas-phase product compounds suggest that human breath can additionally affect indoor air quality through the formation of harmful secondary products and future epidemiological studies should evaluate the potential health effects of these compounds.

Formation of cluster mode particles (1-3 nm) in preschools

This study is the first study that reports the cluster particle (1-3 nm) formation (CPF) in two modern preschools located in Nur-Sultan city of Kazakhstan from October 28 to November 27, 2019. The average particle number concentration and mode diameter values during major CPF events in Preschool I and Preschool II were found to be 1.90 × 10⁶ (SD 6.43 × 10⁶) particles/cm³ and 1.60 (SD 0.85) nm, and 1.11 × 10⁹ (SD 5.46 × 10⁹) particles/cm³ and 2.16 (SD 1.47) nm, respectively. The ultraviolet PM concentration reached as high as 7 μg/m³ in one of the measurement days. The estimated emission rate in Preschool I for CPF events was 9.57 × 10⁹ (SD 1.92 × 10⁹) particles/min. For Preschool II, the emission rate was 7.25 × 10⁹ (SD 12.4 × 10⁹) particles/min. We identified primary cluster particles (CPs) emitted directly from the sources such as candle burning, and secondary CPs formed as a result of the oxidation of indoor VOCs or smoking VOCs. The secondary CPs are likely to be SOA. Indoor VOCs were mainly emitted during cleaning activities as well as during painting and gluing. Indoor VOCs are the controlling factors in the CPF events. Changes in the training and cleaning programs may result in significant reductions in the exposure of the children to CPs.

Nanoscopic Study of Water Uptake on Glass Surfaces with Organic Thin Films and Particles from Exposure to Indoor Cooking Activities: Comparison to Model Systems

Water uptake by thin organic films and organic particles on glass substrates at 80% relative humidity was investigated using atomic force microscopy-infrared (AFM-IR) spectroscopy. Glass surfaces exposed to kitchen cooking activities show a wide variability of coverages from organic particles and organic thin films. Water uptake, as measured by changes in the volume of the films and particles, was also quite variable. A comparison of glass surfaces exposed to kitchen activities to model systems shows that they can be largely represented by oxidized oleic acid and carboxylate groups on long and medium hydrocarbon chains (i.e., fatty acids). Overall, we demonstrate that organic particles and thin films that cover glass surfaces can take up water under indoor-relevant conditions but that the water content is not uniform. The spatial heterogeneity of the changes in these aged glass surfaces under dry (5%) and wet (80%) conditions is quite marked, highlighting the need for studies at the nano- and microscale.

Volatile organic compound emissions during HOMEChem

Quantifying speciated concentrations and emissions of volatile organic compounds (VOCs) is critical to understanding the processes that control indoor VOC dynamics, airborne chemistry, and human exposures. Here, we present source strength profiles from the HOMEChem study, quantifying speciated VOC emissions from scripted experiments (with multiple replicates) of cooking, cleaning, and human occupancy and from unperturbed baseline measurements of the building and its contents. Measurements using a proton transfer reaction time-of-flight mass spectrometer were combined with tracer-based determinations of air-change rates to enable mass-balance-based calculations of speciated, time-resolved VOC source strengths. The building and its contents were the dominant emission source into the house, with large emissions of acetic acid, methanol, and formic acid. Cooking emissions were greater than cleaning emissions and were dominated by ethanol. Bleach cleaning generated high emissions of chlorinated compounds, whereas natural product cleaning emitted predominantly terpenoids. Occupancy experiments showed large emissions of siloxanes from personal care products in the morning, with much lower emissions in the afternoon. From these results, VOC emissions were simulated for a hypothetical 24-h period, showing that emissions from the house and its contents make up nearly half of total indoor VOC emissions.

Visualising household air pollution: Colorimetric sensor arrays for monitoring volatile organic compounds indoors

Indoor air quality monitoring as it relates to the domestic setting is an integral part of human exposure monitoring and health risk assessment. Hence there is a great need for easy to use, fast and economical indoor air quality sensors to monitor the volatile organic compound composition of the air which is known to be significantly perturbed by the various source emissions from activities in the home. To meet this need, paper-based colorimetric sensor arrays were deployed as volatile organic compound detectors in a field study aiming to understand which activities elicit responses from these sensor arrays in household settings. The sensor array itself is composed of pH indicators and aniline dyes that enable molecular recognition of carboxylic acids, amines and carbonyl-containing compounds. The sensor arrays were initially deployed in different rooms in a single household having different occupant activity types and levels. Sensor responses were shown to differ for different room settings on the basis of occupancy levels and the nature of the room emission sources. Sensor responses relating to specific activities such as cooking, cleaning, office work, etc were noted in the temporal response. Subsequently, the colorimetric sensor arrays were deployed in a broader study across 9 different households and, using multivariate analysis, the sensor responses were shown to correlate strongly with household occupant activity and year of house build. Overall, this study demonstrates the significant potential for this type of simple approach to indoor air pollution monitoring in residential environments.

Evaluating Indoor Air Chemical Diversity, Indoor-to-Outdoor Emissions, and Surface Reservoirs Using High-Resolution Mass Spectrometry

Detailed offline speciation of gas- and particle-phase organic compounds was conducted using gas/liquid chromatography with traditional and high-resolution mass spectrometers in a hybrid targeted/nontargeted analysis. Observations were focused on an unoccupied home and were compared to two other indoor sites. Observed gas-phase organic compounds span the volatile to semivolatile range, while functionalized organic aerosols extend from intermediate volatility to ultra-low volatility, including a mix of oxygen, nitrogen, and sulfur-containing species. Total gas-phase abundances of hydrocarbon and oxygenated gas-phase complex mixtures were elevated indoors and strongly correlated in the unoccupied home. While gas-phase concentrations of individual compounds generally decreased slightly with greater ventilation, their elevated ratios relative to controlled emissions of tracer species suggest that the dilution of gas-phase concentrations increases off-gassing from surfaces and other indoor reservoirs, with volatility-dependent responses to dynamically changing environmental factors. Indoor-outdoor emissions of gas-phase intermediate-volatility/semivolatile organic hydrocarbons from the unoccupied home averaged 6-11 mg h^-1, doubling with ventilation. While the largest single-compound emissions observed were furfural (61-275 mg h^-1) and acetic acid, observations spanned a wide range of individual volatile chemical products (e.g., terpenoids, glycol ethers, phthalates, other oxygenates), highlighting the abundance of long-lived reservoirs resulting from prior indoor use or materials, and their gradual transport outdoors.

Reaction Rate Coefficient of OH Radicals with d 9-Butanol as a Function of Temperature

d ₉-Butanol or 1-butan-d ₉-ol (D9B) is often used as an OH radical tracer in atmospheric chemistry studies to determine OH exposure, a useful universal metric that describes the extent of OH radical oxidation chemistry. Despite its frequent application, there is only one study that reports the rate coefficient of D9B with OH radicals, k ₁(295 K), which limits its usefulness as an OH tracer for studying processes at temperatures lower or higher than room temperature. In this study, two complementary experimental techniques were used to measure the rate coefficient of D9B with OH radicals, k ₁(T), at temperatures between 240 and 750 K and at pressures within 2-760 Torr. A thermally regulated atmospheric simulation chamber was used to determine k ₁(T) in the temperature range of 263-353 K and at atmospheric pressure using the relative rate method. A low-pressure (2-10 Torr) discharge flow tube reactor coupled with a mass spectrometer was used to measure k ₁(T) at temperatures within 240-750 K, using both the absolute and relative rate methods. The agreement between the two experimental aproaches followed in this study was very good, within 6%, in the overlapping temperature range, and k ₁(295 ± 3 K) was 3.42 ± 0.26 × 10^-12 cm³ molecule^-1 s^-1, where the quoted error is the overall uncertainty of the measurements. The temperature dependence of the rate coefficient is well described by the modified Arrhenius expression, k ₁ = (1.57 ± 0.88) × 10^-14 × (T/293)^4.60±0.4 × exp(1606 ± 164/T) cm³ molecule^-1 s^-1 in the range of 240-750 K, where the quoted error represents the 2σ standard deviation of the fit. The results of the current study enable an accurate estimation of OH exposure in atmospheric simulation experiments and expand the applicability of D9B as an OH radical tracer at temperatures other than room temperature.

Indoor air quality of 5,000 households and its determinants. Part A: Particulate matter (PM2.5 and PM10-2.5) concentrations in the Japan Environment and Children's Study

Exposure to particulate matter (PM) is one of the important risk factors for morbidity and mortality. Although PM concentrations have been assessed using air quality monitoring stations or modelling, few studies have measured indoor PM in large-scale birth cohorts. The Japan Environment and Children's Study (JECS) measured indoor and outdoor air quality in approximately 5000 households when the participating children were aged 1.5 and 3 years. PM was collected using portable pumps for 7 days (total of 24 h), inside and outside each home. Prediction models for indoor PM concentrations were built using data collected at age 1.5 years and post-validated against data collected at age 3 years. Median indoor/outdoor PM_2.5 and PM_10-2.5 concentrations at age 1.5 years [3 years] were 12.9/12.7 [12.5/11.3] μg/m³ and 5.0/6.3 [5.1/6.1] μg/m³, respectively. Random forest regression analysis found that the major predictors of indoor PM_2.5 were indoor PM_10-2.5, outdoor PM_2.5, indoor smoking, observable smoke and indoor/outdoor temperature. Indoor PM_2.5, outdoor PM_10-2.5, indoor humidity and opening room windows were important predictors of indoor PM_10-2.5 concentrations. Indoor benzene, acetaldehyde, ozone and nitrogen dioxide concentrations were also found to predict indoor PM_2.5 and PM_10-2.5 concentrations, possibly due to the formation of secondary organic aerosols. These findings demonstrate the importance of reducing outdoor PM concentrations, avoiding indoor smoking, using air cleaner in applicable and diminishing sources of VOCs that could form secondary organic aerosols, and the resulting models can be used to predict indoor PM concentrations for the rest of the JECS cohort.

Glass surface evolution following gas adsorption and particle deposition from indoor cooking events as probed by microspectroscopic analysis

Indoor surfaces are extremely diverse and their interactions with airborne compounds and aerosols influence the lifetime and reactivity of indoor emissions. Direct measurements of the physical and chemical state of these surfaces provide insights into the underlying physical and chemical processes involving surface adsorption, surface partitioning and particle deposition. Window glass, a ubiquitous indoor surface, was placed vertically during indoor activities throughout the House Observations of Microbial and Environmental Chemistry (HOMEChem) campaign and then analyzed to measure changes in surface morphology and surface composition. Atomic force microscopy-infrared (AFM-IR) spectroscopic analyses reveal that deposition of submicron particles from cooking events is a contributor to modifying the chemical and physical state of glass surfaces. These results demonstrate that the deposition of glass surfaces can be an important sink for organic rich particles material indoors. These findings also show that particle deposition contributes enough organic matter from a single day of exposure equivalent to a uniform film up to two nanometers in thickness, and that the chemical distinctness of different indoor activities is reflective of the chemical and morphological changes seen in these indoor surfaces. Comparison of the experimental results to physical deposition models shows variable agreement, suggesting that processes not captured in physical deposition models may play a role in the sticking of particles on indoor surfaces.

Cooking and electronic cigarettes leading to large differences between indoor and outdoor particle composition and concentration measured by aerosol mass spectrometry

We spend about two thirds of our time in private homes where airborne particles of indoor and outdoor origins are present. The negative health effects of exposure to outdoor particles are known. The characteristics of indoor airborne particles, though, are not well understood. This study assesses the differences in chemical composition of PM1 (<1 μm) inside and outside of an occupied Swedish residence in real time with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and an Aethalometer. The chemical composition and concentration of particles indoors showed large differences compared to outdoors. The average indoor concentration was 15 μg m-3 and was higher than the outdoor 7 μg m-3. Organics dominated indoor particle composition (86% of the total mass) and originated from indoor sources (cooking, e-cigarette vaping). The average indoor to outdoor ratios were 5.5 for organic matter, 1.0 for black carbon, 0.6 for sulphate, 0.1 for nitrate, 0.2 for ammonium and 0.2 for chloride. The occupancy time accounted for 97% of the total measured period. Four factors were identified in the source apportionment of organic particle fraction by applying positive matrix factorization (PMF): two cooking factors, one e-cigarette factor and one outdoor contribution (OOA) organic factor penetrated from outside.