Source Of Indoor Air Pollution Research Articles

Assessment of the Severity of Indoor Air Pollution Sources and Control Strategies in Printing Presses in Zaria Metropolis, Nigeria

The mitigation of indoor air pollution sources in printing facilities is crucial for ensuring healthy indoor environments and protecting the health and well-being of employees. This study assessed the severity of indoor air pollution sources and the different pollutant control strategies in use in 22 printing presses in Zaria metropolis, Kaduna State. The study adopted a quantitative method. A checklist was used to characterize the selected printing facilities and examine the severity of indoor air pollutant sources on a 5-point Likert severity scale. The instrument was also used to check the availability of Indoor Air Quality (IAQ) monitoring devices and Indoor Air Pollution (IAP) control technology/strategy currently in use in the printing facilities. Findings revealed 1 pollutant source (dust) with mean value of 3.55 to be severe, 9 others to be mild, and 11 to be non-severe. All the assessed printing presses have available compliant inks and coatings, while 100% unavailability of IAQ monitoring devices/equipment or capture systems were observed. The study concluded that by implementing effective control measures and monitoring of indoor air quality, the risk of negative health effects associated with exposure to indoor air pollutants can be minimized in the printing facilities. The study also recommended that Facility managers and policymakers must prioritize the implementation of effective control measures in printing facilities to reduce exposure to indoor air pollutants and improve IAQ, which ultimately promotes the health and well-being of press employees.

A Review of Artificial Neural Network Models Applied to Predict Indoor Air Quality in Schools.

Indoor air quality (IAQ) in schools can affect the performance and health of occupants, especially young children. Increased public attention on IAQ during the COVID-19 pandemic and bushfires have boosted the development and application of data-driven models, such as artificial neural networks (ANNs) that can be used to predict levels of pollutants and indoor exposures. This review summarises the types and sources of indoor air pollutants (IAP) and the indicators of IAQ. This is followed by a systematic evaluation of ANNs as predictive models of IAQ in schools, including predictive neural network algorithms and modelling processes. The methods for article selection and inclusion followed a systematic, four-step process: identification, screening, eligibility, and inclusion. After screening and selection, nine predictive papers were included in this review. Traditional ANNs were used most frequently, while recurrent neural networks (RNNs) models analysed time-series issues such as IAQ better. Meanwhile, current prediction research mainly focused on using indoor PM2.5 and CO2 concentrations as output variables in schools and did not cover common air pollutants. Although studies have highlighted the impact of school building parameters and occupancy parameters on IAQ, it is difficult to incorporate them in predictive models. This review presents the current state of IAQ predictive models and identifies the limitations and future research directions for schools.

Impact of Indoor Air Pollution in Pakistan—Causes and Management

This state-of-the-art review is designed to provide a factual analysis of indoor air pollution in Pakistan. Primarily, the main sources of indoor air pollution and related air pollutants were analyzed. Key sources of indoor air pollution include household energy sources (biomass, wood, coal, tobacco, and low temperatures) producing particulate matter (PM), dust particles, smoke, COx, noxious gases, bioaerosols, airborne microflora, and flame retardants. According to the literature, rural regions of Pakistan using biomass indoor fuels have a high indoor PM concentration in the range of 4000–9000 μg/m3. In rural/urban regions, indoor smoking also leads to high PM2.5 levels of ~1800 μg/m3, which can cause pulmonary infections. In hospitals, PM concentrations were detected up to 1000 μg/m3, causing repeated infections in patients. Indoor ingestion of dust containing polychlorinated biphenyl concentrations was observed at high levels (~8.79–34.39 ng/g) in cities; this can cause serious health effects such as cancer risks and a loss of working productivity. Moreover, indoor microflora and bacteria (~10,000–15,000 cfu m−3) in urban/rural regions cause respiratory/cancer risks. In this context, indoor air quality (IAQ) monitoring and management strategies have been somewhat developed; however, their implementation in Pakistan’s rural/urban indoor environments is still needed. Various challenges were identified for monitoring/regulating IAQ. There is a firm need for industry–academia–research cooperation and for the involvement of government/agencies to support indoor air pollution control/management and for intervention strategies.

69 S-Phenyl Mercapturic Acid as Urinary Biomarker of Indoor Exposure in Children

Abstract Indoor air quality is particularly important for children since they spend more than 90% of their time inside. If outdoor levels of hazardous hydrocarbons are principally traffic related, indoor levels also depend on a variety of sources such as heating and cooking systems, stored products and human behavior (e.g. smoking, cleaning). In this context, within the ENVIRONAGE cohort, was investigated the relationship between SPMA urinary concentration in 214 children (4 to 6-year-old), and indoor sources of air pollution like heating and cooking methods (gas based vs electric) and traffic related air pollution (focusing on NO2 and black carbon). The SPMA urinary concentration was determined developing a high-sensitive UPLC-MS/MS method (LOQ: 0.05 ng/mL). Parents of the children were asked, throughout questionnaire, information about sources of indoor air pollution, such as wood-burning stove, fireplace and gas-based methods of heating or as energy source for the cooking stove and their frequency of using. Interpolation techniques was used to model the regional background levels of NO2 and black carbon for each child's residential address. The use of gas based cooking methods in the residential home of the child was associated with a 74% increase in the mean SPMA concentration of the child (95% Cl: 1.07 to 2.83), correcting for sex, age, BMI, waist circumference, passive smoking, education level of the parents, and time of the day. Consequently, this finding indicates that urinary SPMA can be used as biomarker for looking at indoor determinants of hazard hydrocarbons exposure.

Health Risk Assessment of Polycyclic Aromatic Hydrocarbons from Cooking Fuels burning in Nigeria

Cooking activities are an important source of indoor air pollution which contributes significantly to Polycyclic Aromatic Hydrocarbons (PAHs) in the environment. This study investigated sixteen (16) priority PAHs emitted from smoke in eight (8) cooking fuels commonly used in Nigeria. Gas Chromatography Mass Spectrometry (GC-MS) was used for sample analysis and the potential health risk associated with exposure to PAHs were evaluated. The highest total quantified PAHs concentration was obtained from the burning of palm kernel fiber with an average ΣPAHs of 14.06 mg/kg. The result showed a variation in the average concentration of 10.82 − 14.06 mg/kg for all the cooking fuels. 3-ringed PAHs were found to be the dominant PAHs in the samples considered in terms of concentrations and frequency of occurrence at 7.03-9.42 mg/kg. Benzo[a]anthracene was the most abundant PAHs in biomass materials while Benzo[a]pyrene was the most abundant in liquified petroleum gas and Benzo[b]fluoranthene in kerosene. The cancer risk for both the children and adult obtained for all the cooking fuel samples were less than 10 − 6 which is satisfactory except in sawdust which has a value of 1.30 × 10 − 5 and 1.44 × 10 − 5 for child and adult, respectively. It is recommended that cleaner cooking fuels be used in well-ventilated environments to reduce exposure to these pollutants. Highlights Sixteen priority PAHs in emissions from the burning of eight cooking fuels in Nigeria were investigated Emission sources of the PAHs were identified using diagnostic ratios Health risks of PAHs in emissions from the burning of cooking fuels is higher in adult

Monitoring and apportioning sources of indoor air quality using low-cost particulate matter sensors

Air quality is one of the most important factors in public health. While outdoor air quality is widely studied, the indoor environment has been less scrutinised, even though time spent indoors is typically much greater than outdoors. The emergence of low-cost sensors can help assess indoor air quality. This study provides a new methodology, utilizing low-cost sensors and source apportionment techniques, to understand the relative importance of indoor and outdoor air pollution sources upon indoor air quality. The methodology is tested with three sensors placed in different rooms inside an exemplar house (bedroom, kitchen and office) and one outdoors. When the family was present, the bedroom had the highest average concentrations for PM2.5 and PM10 (3.9 ± 6.8 ug/m3 and 9.6 ± 12.7 μg/m3 respectively), due to the activities undertaken there and the presence of softer furniture and carpeting. The kitchen, while presenting the lowest PM concentrations for both size ranges (2.8 ± 5.9 ug/m3 and 4.2 ± 6.9 μg/m3 respectively), presented the highest PM spikes, especially during cooking times. Increased ventilation in the office resulted in the highest PM1 concentration (1.6 ± 1.9 μg/m3), highlighting the strong effect of infiltration of outdoor air for the smallest particles. Source apportionment, via positive matrix factorisation (PMF), showed that up to 95 % of the PM1 was found to be of outdoor sources in all the rooms. This effect was reduced as particle size increased, with outdoor sources contributing >65 % of the PM2.5, and up to 50 % of the PM10, depending on the room studied. The new approach to elucidate the contributions of different sources to total indoor air pollution exposure, described in this paper, is easily scalable and translatable to different indoor locations.

Alteration In Kidney Biomarkers After Inhalation Exposure of Transfluthrin Based Liquid Mosquito Repellent In Rattus norvegicus (Berkenhout)

The use of liquid mosquito repellent is one of the most significant and persistent sources of indoor air pollution in houses. Human deals with the world's deadliest vector-borne disease, malaria, as well as the fastest-growing vector disease in the world right now, dengue, which is also spread by mosquitoes. Insect-borne diseases are a major public health concern. Transfluthrin, d-allethrin, bioallethrin, dimefluthrin, pralethrin, dphenothrin, cypenothrin, or esbiothrin are some of the more common insecticides contained in mosquito repellents. All of them are pyrethroid derivatives. After 7, 15, 30, 45 and 60 days of exposure to liquid insect repellent in the treated group as compared to the control group, Rattus norvegicus (Berkenhout) showed substantial increases in kidney biomarkers Urea, Creatinine, Uric acid and Blood Urea Nitrogen (BUN). The current study shows that different kidney biomarkers are adversely affected by liquid mosquito repellent. The main component of this repellent is lethal and dangerous for both people and the environment. Keywords : Repellent, Insecticides, Transfluthrin, Pyrethroid

Sources of Indoor Air Pollution in Schools in Kosovo

There is increasing scientific evidence of the adverse health effects of indoor exposure to a collective mixture of chemicals in children. People spend 80–90% of their time indoors, breathing air that is often even more polluted than the air outside. This study presents results of school inspection and sampling of selected chemical pollutants—formaldehyde, benzene, and nitrogen dioxide—in classrooms and outdoors in ten schools in Kosovo, conducted by the National Institute of Public Health and the WHO. Nitrogen dioxide and benzene were most affected by outdoor concentrations and were too high in at least one school (NO2: >80 µg/m3, benzene: 1–2 µg/m3). Formaldehyde was significantly higher indoors than outdoors and higher in newer schools than older ones, but overall levels were not alarming (maximum around 20 µg/m3). CO2 levels during class indicated insufficient ventilation. The temperatures were occasionally too high during the cold season. This not only results in unnecessary energy wastage but also too low relative humidity. Improvements in air circulation and temperature control, as well as the identification and elimination of certain sources of pollution would improve the health and learning of school children.

The association between different types of cooking fuels and common health problems: north India region

Background: The fuel used for cooking is a major source of indoor air pollution because of inefficient combustion and inadequate ventilation. This study was conducted to see if there is any association between the type of cooking fuel and common health problems in light of inadequate ventilation. Methods: This was a cross-sectional study; 688 subjects were selected randomly from various sectors and the outlying areas of Surajkund. The impact of indoor air pollution on health was assessed by questionnaires, general physical examination, and pulmonary function testing. Results: One of the key findings of the study has been the implication of LPG, touted as a safe, non-polluting fuel with a definite negative impact on health. There was significantly more breathlessness experienced by LPG users as opposed to the users of wood and cow dung. Though the prevalence of fever in both groups was similar, chest pain, burning of eyes, and fatigue were reported by wood and cow dung users much more frequently. The pulmonary function test showed restrictive pathology in cow dung and wood users, whereas obstructive pathology in LPG users. Conclusions: LPG is considered “clean” fuel because it does not produce visible emissions. However, improper burner design, blocking and clogging of the flue vent, and insufficient combustion air result in improper combustion and the emission of aldehydes, CO, hydrocarbons, and other organics. It would be folly to believe that LPG is harmless. Even a harmless material may become harmful if used inappropriately.

Association between incense burning and prenatal depressive symptoms: evidence from the Born in Guangzhou Cohort Study.

This study aimed to examine the association of incense burning alone, a source of indoor air pollution, and jointly with passive smoking, with prenatal depressive symptoms. Information on incense exposure and depressive symptoms were collected at both early and late pregnancy using questionnaires in the Born in Guangzhou Cohort Study. Mixed-effects logistic regression models were used to assess the associations of incense exposure separately, and together with passive smoking, with prenatal depressive symptoms. Compared to the non-users, pregnant women with household incense burning had higher odds of depressive symptoms (odds ratio (OR), 1.17, 95% CI, 1.06, 1.28). Compared with non-users, women who occasionally (OR, 1.22, 95% CI, 1.09, 1.36) and frequently (1.51, 95% CI, 1.26, 1.80) smelled incense had higher odds of prenatal depressive symptoms. Higher duration of incense smelling was associated with higher odds of prenatal depressive symptoms compared with non-users. There was no strong evidence for an interaction of frequency of incense smelling and passive smoking in prenatal depressive symptoms. Prenatal exposure to incense burning was associated with higher odds of having depressive symptoms during pregnancy, and there is no evidence for interaction with concurrent exposure to passive smoking.

Characterization of organic release kinetics in particleboard using a dual model fitting methodology.

In modern society, people spend most of their time indoors engaging in their work and home life. However, indoor air pollution is a potential risk to health, and it is associated with many diseases. Wooden furniture, as the most popular indoor furniture used in modern times, is a major source of indoor air pollution, so it has become imperative to explore the composition and release kinetics characteristics of toxic and hazardous substances from wood-based panels. In this study, thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) was used to detect the release of organic compounds from wood panels, and determine the release kinetics of the organic compounds dimethyl acetal, phenol, toluene and decanoic acid via bi-exponential and mass transfer models to provide a theoretical basis for targeted pollution prevention and control. In this project, a climate chamber method was used to conduct a 120 h continuous sampling of the release concentration of compounds from wood panels. The TD-GC-MS method was used to analyze the sampling tubes, and the concentration-time data were fitted to the bi-exponential and mass transfer models. The emission factor equation was obtained from the bi-exponential model. The critical physical parameters, such as the initial internal release concentration C0, internal diffusion rate Dm, and solid-phase/gas-phase partition coefficient K, were obtained from the mass transfer model. Finally, it was found that dimethyl acetal and toluene were easily and rapidly released into the air, while phenol and decanoic acid were slowly released into the ambient air. The two sets of release kinetics characteristics provide an essential theoretical basis for targeted pollution prevention and control, as well as a methodological path for studying the release kinetics of different toxic and hazardous substances.

A measurement and modelling investigation of the indoor air chemistry following cooking activities.

Domestic cooking is a source of indoor air pollutants, including volatile organic compounds (VOCs), which can impact on indoor air quality. However, the real-time VOC emissions from cooking are not well characterised, and similarly, the resulting secondary chemistry is poorly understood. Here, selected-ion flow-tube mass spectrometry (SIFT-MS) was used to monitor the real-time VOC emissions during the cooking of a scripted chicken and vegetable stir-fry meal, in a room scale, semi-realistic environment. The VOC emissions were dominated by alcohols (70% of total emission), but also contained a range of aldehydes (14%) and terpenes (5%), largely attributable to the heating of oil and the preparation and heating of spices, respectively. The direct cooking-related VOC emissions were then simulated using the Indoor Chemical Model in Python (INCHEM-Py), to investigate the resulting secondary chemistry. Modelling revealed that VOC concentrations were dominated by direct emissions, with only a small contribution from secondary products, though the secondary species were longer lived than the directly emitted species. Following cooking, hydroxyl radical concentrations reduced by 86%, while organic peroxy radical levels increased by over 700%, later forming secondary organic nitrates, peroxyacylnitrates (PANs) and formaldehyde. Monoterpene emissions were shown to drive the formation of secondary formaldehyde, albeit to produce relatively modest concentrations (average of 60 ppt). Sensitivity analysis of the simulation conditions revealed that increasing the outdoor concentrations of ozone and NOx species (2.9× and 9×, respectively) resulted in the greatest increase in secondary product formation indoors (≈400%, 200% and 600% increase in organic nitrates, PANs and formaldehyde production, respectively). Given the fact that climate change is likely to result in increased ozone concentrations in the future, and that increased window-opening in response to rising temperatures is also likely, higher concentrations of indoor oxidants are likely in homes in the future. This work, therefore, suggests that cooking could be a more important source of secondary pollutants indoors in the future.

Indoor volatile and semi-volatile organic toxic compounds: Need for global action

Indoor air pollution results in mortalities worldwide, burdening especially the low- and middle-income countries. The volatile and semi-volatile organic compounds (VOCs and SVOCs) emitted from indoor structures and furniture materials are important sources of indoor air pollution. Exposure to VOCs, such as formaldehyde and benzene, has been associated with higher risk of reproductive problems, respiratory complications, immune suppression, cancers, and dementia. SVOCs are typically found in carpets, textiles, furniture, electronics and cosmetics. These chemicals are also neurotoxic, inducing a number of adverse health effects, behavioral changes, learning disability, and the impairment of locomotor activity. If not mitigated, indoor air pollution will continue to impose health and socioeconomic burden on both individuals and societies. Solutions to curb their environmental occurrences include those that reduce/eliminate the material sources of indoor VOCs/SVOCs and those that increase their removal, including phytoremediation and metal-organic frameworks to reduce their indoor concentrations. As such, there is an urgent need to tackle this problem by better regulating the indoor concentrations of these chemicals and developing and upscaling solutions to mitigate their health effects, using advanced, accessible, and environmentally sustainable materials, electronics and technologies.

Health impact of indoor air pollution in the gulf region: A review

Factors such as unfavorable meteorological conditions within the Gulf region force citizens to spend a considerable amount of time in their homes. Indoor air quality in the Arabian Gulf is rapidly becoming an issue of vital concern that requires urgent governmental intervention and control measures as well as increased in-depth research on likely health consequences. In this review, we surveyed the current literature on the potential health impact of daily household activities in Gulf Cooperation Council (GCC) countries like Qatar where practiced traditions such as burning incense and scented candles are commonplace. These may increase indoor pollution levels, and worsen the health conditions of residents. The main goal of this review is to assess the extent of common indoor pollutants and suggest strategies of pollution control that may alleviate pollution concentration in an indoor environment. Creating awareness about the most common sources of indoor air pollution in the GCC may help improve health promotion and lifestyle changes, especially with respect to reproductive health that is a major concern in the region. The government may also explore recommendations for more environmentally friendly incense and organic candles.

Association between the domestic use of solid cooking fuel and increased prevalence of depression and cognitive impairment in a big developing country: A large-scale population-based study.

Previous studies have suggested that air pollution affects physiological and psychological health. Using solid fuel at home is a significant source of indoor air pollution. The associations between solid fuel use and depressive symptoms and cognitive health were unclear among older adults from low- and middle-income countries (LMICs). To evaluate the association of solid fuel use with depressive symptoms and cognitive health among older adults, we obtained data from the Longitudinal Aging Study in India (LASI) and excluded subjects younger than 60 years and without critical data (solid fuel use, depressive symptoms, and cognitive health). The 10-item Center for Epidemiologic Studies Depression Scale (CES-D-10) was used to assess depressive symptoms, with more than ten indicative of depression. Cognitive health was assessed using measures from the Health and Retirement Study (HRS), and subjects with the lowest 10th percentile were considered to have cognitive impairment. The participants' responses defined solid fuel use. Multivariable logistic regression, linear regression, subgroup analysis, and interaction tests were performed to appraise the relationship between solid fuel use and depression and cognitive impairment. A total of 29,789 participants over 60 years old were involved in this study. Almost half of the participants (47.5%) reported using solid fuel for home cooking. Compared with clean fuel use, solid fuel use was related to an increased prevalence of depression [odds ratio (OR) 1.09, 95% CI 1.03-1.16] and higher CES-D-10 scores (β 0.23, 95% CI 0.12-0.35) after fully adjusted covariables. Using solid fuel was also related to a higher risk of cognitive impairment (OR 1.21, 95% CI 1.11-1.32) and a lower cognitive score (β -0.63, 95% CI -0.79 to -0.47) compared with those who used clean fuel. In the subgroup analysis, the prevalence of depression increased in females and non-smokers. The association of solid fuel use with depression and cognitive impairment exists in subgroups of BMI, economic status, caste, living area, education, and drinking. The use of solid fuel at home was associated with an increased prevalence of depression and cognitive impairment among older adults in India.

The Effect of Students, Computers, and Air Purifiers on Classroom Air Quality

Indoor air pollutant sources are crucial in assessing IAQ, especially when outdoor air pollutant concentrations are low. In the present study, PM mass concentrations in a range of five sizes; CO, CO2, O3, NO, NO2, and TVOC concentrations; along with temperature and relative humidity were monitored in three indoor locations of a university. The monitoring took place in a building dedicated to teaching undergraduates. The first two locations, a professor’s office and a computer centre (laboratory), were not refurbished. The classroom under study is refurbished and now is airtight, as are all of the classrooms in this building. Air purifiers were installed in all of the classrooms to prevent the transmission of infectious pollutants. In all monitored locations, people were the main indoor source of PM, CO2, and TVOC. The operation of twelve computers in the small laboratory did not contribute to the air pollution, at least for the examined pollutants. The air purifier decreased the PM concentrations, but not the gaseous air pollutants.

Do Storage Conditions Affect Collected Cookstove Emission Samples? Implications for Field Studies

Cookstove emissions are a significant source of indoor air pollution in developing countries and rural communities world-wide. Considering that many research sites for evaluating cookstove emissions and interventions are remote and require potentially lengthy periods of particulate matter (PM) filter sample storage in sub-optimal conditions (e.g., lack of cold storage), an important question is whether samples collected in the field are stable over time. To investigate this, red oak was burned in a natural-draft stove, and fine PM (PM2.5) was collected on polytetrafluoroethylene filters. Filters were stored at either ambient temperature or more optimal conditions (−20 °C or −80 °C) for up to 3 months and extracted. The effects of storage temperature and length on stability were evaluated for measurements of extractable organic matter (EOM), PM2.5, and polycyclic aromatic compound (PAC) levels in the filter extracts. A parallel, controlled laboratory condition was also evaluated to further explore sources of variability. In general, PM2.5 and EOM in both simulated field and laboratory samples were similar regardless of the storage condition or duration. The extracts were also analyzed by gas chromatography to quantify 22 PACs and determine similarities and/or differences between the conditions. PAC levels were a more sensitive stability measure in differentiating between storage conditions. The findings suggest that measurements are relatively consistent across storage duration/temperatures for filter samples with relatively low EOM levels. This study aims to inform protocols and filter storage procedures for exposure and intervention research conducted in low- and middle-income countries where studies may be budget- and infrastructure-limited.

Rapid determination of chemical concentration and odor concentration of paint-emitted pollutants using an electronic nose

Volatile pollutants emitted from building materials are an important source of indoor air pollution. The development of rapid determination methods for the chemical concentration and odor concentration of these volatile pollutants is of great importance. The present work investigated the difference in the concentration of pollutants emitted by various paint samples, from which key pollutants (methyl isobutyl ketone, ethylbenzene, and xylene) were screened based on their concentration and odor contribution. Then, an electronic nose (E-nose) device was developed to determine the chemical concentrations of key pollutants and the odor concentration of gas emitted by paint samples. A total of 135 gas samples emitted by the selected paint were measured by the developed E-nose, by gas chromatography–mass spectrometry and by olfactory testing. The obtained sensor response values and chemical and odor concentrations were divided randomly and used for training and testing of the E-nose pattern recognition algorithm. The trained pattern recognition algorithm was able to accurately output the target values, with average relative errors of 10.0%, 10.4%, 7.6%, and 10.0% (test set, n = 13) for the methyl isobutyl ketone, ethylbenzene, and xylene chemical concentrations and the odor concentration, respectively. In addition, the cross-sensitive nature of the E-nose showed a unique advantage in determining odor concentration compared to the odor conversion model. The excellent performance of the developed E-nose demonstrates that this work provides a practical solution for the rapid determination of the chemical concentration and odor concentration of pollutants emitted by building materials.

Chemical characterization and health risk assessment of VOCs and PM2.5-bound PAHs emitted from typical Chinese residential cooking

Cooking is a major source of indoor air pollution. Existing studies suggest that organic material is the most abundant component by mass in cooking emissions, while the detailed organic species that result from cooking remains poorly understood. This work provides a comprehensive foundational knowledge of emission arising from typical Chinese residential cooking based on a field-work measurement of polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), and the routinely measured fine particulate matter (PM2.5) composition. Exposure to the Chinese cooking procedures will likely pose a significant health risk, with grilling producing the highest PM2.5 concentration (28.79 ± 9.36 mg m−3) and the most distinctive composition among the cooking patterns. The PAHs with 3 rings dominated the total PAHs by mass (48.08%), with the major organic species Phenanthrene (Phe), Anthracene (Ant), Benzo [a] pyrene (BaP), and Fluorene (Flu), accounting for 0.0399–0.5966, 0.0091–0.6710, 0.0046–0.4531, and 0.0086–0.3102 ng per μg of PM2.5, respectively. Oxygenated VOCs (OVOCs) accounted for 37.98% of the total VOCs. The ratios of Fla/(Fla + Pyr) and IcdP/(IcdP + BghiP) helped in distinguishing residential cooking emissions from other sources. The incremental lifetime cancer risk (ILCR) values of PAHs and VOCs were 6.9 × 10−6–1.8 × 10−5 and 2.7 × 10−6–1.8 × 10−3, respectively, which were substantially higher than the acceptable levels (1.0 × 10−6) established by the U.S. EPA. The considerable health risks posed by Chinese cooking emissions necessitate additional study and control measures to lessen indoor air pollution and protect human health.

Size-fractionated ultrafine particles and their optical properties produced from heating edible oils in a kitchen laboratory

Cooking oil fume (COF) is an important source of indoor and outdoor air pollutants. COF generates a large number of organic compounds through volatilization and thermal oxidation, mainly including acids, alcohols, aldehydes and polycyclic aromatic hydrocarbons (PAHs), which can contribute 10 %–35 % to airborne organic particles in urban areas. COF not only affects human health owning to their small sizes, but also may absorb incident light due to the presence of brown carbon (BrC) chromophores in organic components. Therefore, we investigated size distributions and light absorption properties of particles produced from heating four types of edible oil. Results showed over 75 % of COF particles belonged to ultrafine particles (UFPs) and capable of absorbing light. The particle number size distributions for heating all edible oils were bimodal lognormal distribution, and the two mode diameters were within 27.9–32.2 nm and 187.7–299.6 nm. Both real-time monitoring and offline analyzing results show the average absorption coefficients of particles generated from heating soybean oil were much greater compare to those of heating other three edible oils. The mean AAE370/520 for heating soybean oil, olive oil, corn oil and peanut oil were 1.877, 1.669, 1.745 and 1.288, respectively, indicating the presence of BrC chromophores. A large proportion of BrC identified by HPLC-DAD-Q-TOF-MS only contain carbon, hydrogen and oxygen, which are CnH2nO2, CnH2n-2O2, CnH2n-4O2 and CnH2n-6O2 (9 <n < 23), may belong to fatty acids. Their total light absorption at λ = 370 nm accounted for 16.75 %–54.56 % of the total absorption of methanol-soluble BrC. The findings provided scientific evidences for the significance of cooking emissions on ambient aerosol properties.