Ultrafine particles and nitrogen oxides generated by gas and electric cooking

NPCC4: Climate change, energy, and energy insecurity in New York City

This chapter of the New York City Panel on Climate Change 4 (NPCC4) report provides an overview of energy trends in New York City and the State of New York, as well as accompanying challenges and barriers to the energy transition-with implications for human health and wellbeing. The link between energy trends and their impact on health and wellbeing is brought to the fore by the concept of "energy insecurity," an important addition to the NPCC4 assessment.

Reconsidering gas as clean energy: Switching to electricity for household cooking to reduce NO2-attributed disease burden

Nitrogen dioxide (NO2) is a prevalent air pollutant in urban areas, originating from outdoor sources, household gas consumption, and secondhand smoke. The limited evaluation of the disease burden attributable to NO2, encompassing different health effects and contributions from various sources, impedes our understanding from a public health perspective. Based on modeled NO2 exposure concentrations, their exposure-response relationships with lung cancer, chronic obstructive pulmonary disease, and diabetes mellitus, and baseline disability-adjusted life years (DALYs), we estimated that 1,675 (655-2,624) thousand DALYs were attributable to NO2 in urban China in 2019 [138 (54-216) billion Chinese yuan (CNY) economic losses]. The transition from gas to electricity for household cooking was estimated to reduce the attributable economic losses by 35%. This reduction falls within the range of reductions achieved when outdoor air meets the World Health Organization interim target 3 and air quality guidelines for annual NO2, highlighting the significance of raising awareness of gas as a polluting household energy for cooking. These findings align with global sustainable development initiatives, providing a sustainable solution to promote public health while potentially mitigating climate change.

Gas cooking indoors and respiratory symptoms in the ECRHS cohort

BACKGROUND

Gas cooking is an important source of indoor air pollutants, and there is some limited evidence that it might adversely be associated with respiratory health. Using repeated cross-sectional data from the multi-centre international European Community Respiratory Health Survey, we assessed whether adults using gas cookers have increased risk of respiratory symptoms compared to those using electric cookers and tested whether there was effect modification by a priori selected factors.

METHODS

Data on respiratory symptoms and gas cooking were collected from participants at 26-55 and 38-67 years (median time between examinations 11.4 years) from interviewer-led questionnaires. Repeated associations between gas cooking (versus electric) and respiratory symptoms were estimated using multivariable mixed-effects logistic regression models adjusted for age, sex, study arm, smoking status, education level, and included random intercepts for participants within study centres. Analyses were repeated using a 3-level variable for type of cooker and gas source. Effect modification by ventilation habits, cooking duration, sex, age atopy, asthma, and study arm were examined.

RESULTS

The sample included 4337 adults (43.7% males) from 19 centres in 9 countries. Gas cooking increased the risk of "shortness of breath whilst at rest" (OR = 1.38; 95%CI: 1.06-1.79) and "wheeze with breathlessness" (1.32; 1.00-1.74). For several other symptoms, effect estimates were larger in those who used both gas hobs and ovens, had a bottled gas source and cooked for over 60 min per day. Stratifying results by sex and age found stronger associations in females and younger adults.

CONCLUSION

This multi-centre international study, using repeat data, suggested using gas cookers in the home was more strongly associated than electric cookers with certain respiratory symptoms in adults. As gas cooking is common, these results may play an important role in population respiratory health.

Cooking oil fume exposure and Lung-RADS distribution among school cafeteria workers of South Korea

Background

Cooking oil fumes (COFs) from cooking with hot oil may contribute to the pathogenesis of lung cancer. Since 2021, occupational lung cancer for individual cafeteria workers has been recognized in South Korea. In this study, we aimed to identify the distribution of lung-imaging reporting and data system (Lung-RADS) among cafeteria workers and to determine factors related to Lung-RADS distribution.

Methods

We included 203 female participants who underwent low-dose computed tomography (LDCT) screening at a university hospital and examined the following variables: age, smoking status, second-hand smoke, height, weight, and years of service, mask use, cooking time, heat source, and ventilation. We divided all participants into culinary and non-culinary workers. Binomial logistic regression was conducted to determine the risk factors on LDCT of Category ≥ 3, separately for the overall group and the culinary group.

Results

In this study, Lung-RADS-positive occurred in 17 (8.4%) individuals, all of whom were culinary workers. Binary logistic regression analyses were performed and no variables were found to have a significant impact on Lung-RADS results. In the subgroup analysis, the Lung-RADS-positive, and -negative groups differed only in ventilation. Binary logistic regression showed that the adjusted odds ratio (aOR) of the Lung-RADS-positive group for inappropriate ventilation at the workplace was 14.89 (95% confidence interval [CI]: 3.296-67.231) compared to appropriate ventilation as the reference, and the aOR for electric appliances at home was 4.59 (95% CI: 1.061-19.890) using liquid fuel as the reference.

Conclusions

The rate of Lung-RADS-positive was significantly higher among culinary workers who performed actual cooking tasks than among nonculinary workers. In addition, appropriate ventilation at the workplace made the LDCT results differ. More research is needed to identify factors that might influence LDCT findings among culinary workers, including those in other occupations.

Exposure to different residential indoor characteristics during childhood and asthma in adolescence: a latent class analysis of the Danish National Birth Cohort

BACKGROUND

Many residential indoor environments may have an impact on children's respiratory health.

OBJECTIVES

The aims of this study were to identify latent classes of children from the Danish National Birth Cohort (DNBC) who share similar patterns of exposure to indoor home characteristics, and to examine the association between membership in the latent classes and asthma in adolescence.

METHODS

We included data on residential indoor characteristics of offspring from the DNBC whose mothers had responded to the child's 11-year follow-up and who had data on asthma from the 18-year follow-up. Number of classes and associations were estimated using latent class analysis. To account for sample selection, we applied inverse probability weighting.

RESULTS

Our final model included five latent classes. The probability of current asthma at 18 years was highest among individuals in class one with higher clustering on household dampness (9, 95%CI 0.06-0.13). Individuals in class four (with higher clustering on pets ownership and living in a farm) had a lower risk of current asthma at age 18 compared to individuals in class one (with higher clustering on household dampness) (OR 0.53 (95%CI 0.32-0.88), p = .01).

CONCLUSION

Our findings suggest that, in a high-income country such as Denmark, groups of adolescents growing up in homes with mold and moisture during mid-childhood might be at increased risk of current asthma at age 18. Adolescents who grew-up in a farmhouse and who were exposed to pets seem less likely to suffer from asthma by age 18.

Indoor exposure to ultrafine particles related to domestic activities: A systematic review and meta-analysis

Ultrafine particles (< 100 nm) are of increasing concern because of their toxicological potential. Emission processes suggest their presence in all environments, including at home, where particularly at-risk populations may be exposed. However, knowledge of their impact on health is still limited, due to difficulties in properly assessing exposure in epidemiological studies. In this context, the objective of this study was to provide a complete summary of indoor exposure to ultrafine particles in highly industrialised countries by examining the domestic activities that influence such exposure. We conducted a systematic review, according to PRISMA guidelines using PubMed, Web of Science and Scopus up to and including 2021. We carried out a qualitative and quantitative analysis of the selected studies with a standardised template. Exposure circumstances, measurement methods, and results were analysed. Finally, a meta-analysis of the measured concentrations was performed to study exposure levels during domestic activities. The review included 69 studies resulting in the analysis of 346 exposure situations. Nine main groups of activities were identified: cooking, which was the most studied, smoking, the use of air-fresheners, cleaning, heating, personal care, printing, do-it-yourself activities, and others. Over 50 different processes were involved in these activities. Based on available particle number concentrations, the highest average of mean concentrations was associated with grilling (14,400 × 103 cm-3), and the lowest with wood stove (18 × 103 cm-3). The highest average of peak concentrations was that for the use of hair dryers (695 × 103 cm-3), and the lowest for the use of air cleaners (11 × 103 cm-3). A hierarchy of domestic activities and related processes leading to ultrafine particle exposure is provided, along with average exposure concentrations at home. However, more extensive measurement campaigns are needed under real-life conditions to improve assessments of indoor exposure to ultrafine particles.

Particulate Matter and Volatile Organic Compound Emissions Generated from a Domestic Air Fryer

Air frying has become a popular cooking method for domestic cooking, but the level of released indoor air pollutants is poorly understood. In this work, we compared particle and gas phase emission factors (EF) and particle size distributions between cooking with a domestic air fryer and a pan for a variety of foods. The PM10 EFs of air frying chicken wings and breast were higher than pan cooking by a factor of 2.1 and 5.4, respectively. On the other hand, a higher PM10 emission factor from air frying can be achieved by increasing the amount of oil to levels similar to or above those from pan-frying for French fries and asparagus. We propose that higher temperature and greater turbulence lead to higher PM10 EFs for cooking with the air fryer compared with the pan for the same mass of oil added. EFs of volatile organic compounds (VOCs) are also generally higher for cooking with the air fryer compared with the pan: 2.5 times higher for French fries and 4.8 times higher for chicken breast. Our study highlights the potential risk of higher indoor PM10 levels associated with domestic air frying under certain cases and proposes possible mitigation measures.

Photochemical renoxification on commercial indoor photoactive paint

Surface chemistry plays an important role in the indoor environment owing to the large indoor surface to volume ratio. This study explores the photoreactivity of surfaces painted with a photoactive paint in the presence of NOx. Two types of experiments are performed; illumination of painted surfaces with a nitrate deposit and illumination of painted surfaces in the presence of gaseous NO. For both types of experiments, illumination with a fluorescent bulb causes the greatest change in measured gaseous NOx concentrations. Results show that relative humidity and paint composition play an important role in the photoreactivity of indoor painted surfaces. Painted surfaces could contribute to gas-phase oxidant concentrations indoors.

Climate and health benefits of a transition from gas to electric cooking

Household electrification is thought to be an important part of a carbon-neutral future and could also have additional benefits to adopting households such as improved air quality. However, the effectiveness of specific electrification policies in reducing total emissions and boosting household livelihoods remains a crucial open question in both developed and developing countries. We investigated a transition of more than 750,000 households from gas to electric cookstoves-one of the most popular residential electrification strategies-in Ecuador following a program that promoted induction stoves and assessed its impacts on electricity consumption, greenhouse gas emissions, and health. We estimate that the program resulted in a 5% increase in total residential electricity consumption between 2015 and 2021. By offsetting a commensurate amount of cooking gas combustion, we find that the program likely reduced national greenhouse gas emissions, thanks in part to the country's electricity grid being 80% hydropower in later parts of the time period. Increased induction stove uptake was also associated with declines in all-cause and respiratory-related hospitalizations nationwide. These findings suggest that, when the electricity grid is largely powered by renewables, gas-to-induction cooking transitions represent a promising way of amplifying the health and climate cobenefits of net-carbon-zero policies.

Spatial distributions of particle number size distributions generated during cooking processes and the impacts of range hoods

Cooking oil fume (COF) is associated with an increased risk of health effects. The particle number size distribution (PNSD) of COF presenting as lognormal structures is recognized as a key metric in determining its exposure toxicities, but the information of its spatial distributions and impacting factors are still lacking. This study conducted real-time monitoring COF PNSD during the cooking processes in a kitchen laboratory. Results showed that COF PNSD presented as a combination of two lognormal distributions. The peak diameters of PNSD inside the kitchen were: 385 nm (very close to the source), 126 nm (5 cm above the source), 85 nm (10 cm above the source) to 36 nm (breath point, 50 cm above the source), 33 nm (sucking surface of the ventilation hood), 31 nm (1 m horizontally to the source), and 29 nm (3.5 m horizontally to the source). The reasons of this observation was the sharp decrease of temperature from the pot to the indoor environment reduced the surface partial pressure of the COF particles and caused a large amount of semi-volatile organic carbons (SVOCs) with lower saturation ratios condensed on the COF surface. With the temperature difference became insignificant with the distance further to the source, the reduction of the supersaturation helped the gasification of these SVOCs. Dispersion led to a linearly horizontal decreases ((1.85 ± 0.10) × 10⁶#/cm³/m) in particle numbers with further distances, making the peak particle number concentrations decrease from 3.5 × 10⁵#/cm³ at the breath point to 1.1 × 10⁵#/cm³ at the point 3.5 m to the source. Cooking dishes also presented as mode diameters of 22-32 nm at the breath point. The amount of edible oil used in different dishes is positively correlated with the peak concentration of COF. Only increasing the exhaust force of the range hood cannot significantly change the sucked COF particle numbers and sizes, owning to that COF particles are mainly small sizes. New technologies on cleaning small size particles and efficient supplemental air should be given more considerations.

Cooking methods and kitchen ventilation availability, usage, perceived performance and potential in Canadian homes

BACKGROUND

Cooking is a substantial contributor to air pollutant exposures in many residences. Effective use of kitchen ventilation can mitigate exposure; however, information on its availability, usage, and potential to increase its use across the population has been limited.

OBJECTIVE

This study aimed to obtain nationally representative information on cooking methods, kitchen ventilation availability and usage, and the potential for education to increase effective usage.

METHODS

An online survey was sent to a representative sample of Canadian homes to collect data on cooking methods, the presence and use of mechanical kitchen ventilation devices, perceived device performance, and willingness to implement mitigation strategies. Responses were weighted to match key demographic factors and analyzed using non-parametric statistics.

RESULTS

Among the 4500 respondents, 90% had mechanical ventilation devices over the cooktop (66% of which were vented to the outside), and 30% reported regularly using their devices. Devices were used most often for deep-frying, followed by stir-frying, sautéing or pan-frying, indoor grilling, boiling or steaming. Almost half reported rarely or never using their ventilation devices during baking or oven self-cleaning. Only 10% were fully satisfied with their devices. More frequent use was associated with the device being vented to the outdoors, having more than two speed settings, quiet operation if only one speed, covering over half of the cooktop, and higher perceived effectiveness. After being informed of the benefits of kitchen ventilation, 64% indicated they would consider using their devices more often, preferentially using back burners with ventilation, and/or using higher ventilation device settings when needed.

IMPACT

This study provides population-representative data on the most used cooking methods, kitchen ventilation availability and usage, and influencing factors in Canadian homes. Such data are needed for exposure assessments and evaluating the potential to mitigate cooking-related pollutant exposures via more effective use of kitchen ventilation. The data can be reasonably extrapolated to the United States, given the similarities in residential construction practices and cultural norms between the two countries.

Impacts of solid fuel use versus smoking on life expectancy at age 30 years in the rural and urban Chinese population: a prospective cohort study

Background

The impact of solid fuel use on life expectancy (LE) in less-developed countries remains unclear. We aimed to evaluate the potential impact of household solid fuel use on LE in the rural and urban Chinese population, with the effect of smoking as a reference.

Methods

We used data from China Kadoorie Biobank (CKB) of 484,915 participants aged 30-79 free of coronary heart disease, stroke, or cancer at baseline. Analyses were performed separately for solid fuel use for cooking, solid fuel use for heating, and smoking, with participants exposed to the other two sources excluded. Solid fuels refer to coal and wood, and clean fuels refer to electricity, gas, and central heating. We used a flexible parametric Royston-Parmar model to estimate hazard ratios of all-cause mortality and predict LE at age 30.

Findings

Totally, 185,077, 95,228, and 230,995 participants were included in cooking-, heating-, and smoking-related analyses, respectively. During a median follow-up of approximately 12.1 years, 12,725, 7,531, and 18,878 deaths were recorded in the respective analysis. Compared with clean fuel users who reported cooking with ventilation, participants who used solid fuels with ventilation and without ventilation had a difference in LE (95% confidence interval [CI]) at age 30 of -1.72 (-2.88, -0.57) and -2.62 (-4.16, -1.05) years for men and -1.33 (-1.85, -0.81) and -1.35 (-2.02, -0.67) years for women, respectively. The difference in LE (95% CI) for heating was -2.23 (-3.51, -0.95) years for men and -1.28 (-2.08, -0.48) years for women. In rural men, the LE reduction (95% CI) related to solid fuel use for cooking (-2.55; -4.51, -0.58) or heating (-3.26; -6.09, 0.44) was more than that related to smoking (-1.71; -2.54, -0.89). Conversely, in urban men, the LE reduction (95% CI) related to smoking (-3.06; -3.56, -2.56) was more than that related to solid fuel use for cooking (-1.28; -2.61, 0.05) and heating (-1.90; -3.16, -0.65). Similar results were observed in women but with a smaller magnitude.

Interpretation

In this Chinese population, the harm to LE from household use of solid fuels was greater than that from smoking in rural residents. Conversely, the negative impact of smoking was greater than solid fuel use in urban residents. Our findings highlight the complexity and diversity of the factors affecting LE in less-developed populations.

Funding

National Natural Science Foundation of China, National Key R&D Program of China, Kadoorie Charitable Foundation, UK Wellcome Trust.

Size fraction of hazardous particulate matter governing the respiratory deposition and inhalation risk in the highly polluted city Delhi

Delhi has been identified as one of the highly polluted cities in the world and recently associated with the highest population weighted PM2.5 concentration. However, the unavailability of the health risk estimations using long-term data for Indian cities has been pointed out as a hurdle in performing the correct assessment. The present work estimated deposition of particles in different regions of respiratory systems (head airway = 67% deposition for 2.5 µm particles; tracheo-bronchiolar (TB) = 73% deposition for 1.0 µm particles; alveolar (AL) = 17% deposition for 0.5 µm, 0.25 µm, and < 0.25 µm particles) using PM samples collected at a breathing height of 1.5 m near the major ring road in New Delhi (India). The calculated risk index (RI) varied considerably between winter (1.21 ± 0.26 to 1.33 ± 0.50) and pre-monsoon-southwest monsoon months (0.34 ± 0.08 to 0.96 ± 0.27). Respiratory deposition dose of nanosized particles (≤ 500 nm) in the alveoli region of the lung was found to be considerable (35%) indicating the need for understanding the role of these particles in posing health risk. Although the calculated values of risk metric for exposures of PM-associated metals indicated no risk to IIT Delhi population (hazard quotient < 1 and excess risk of getting cancer < 10-6-10-9), continuous monitoring for particles of different sizes at inhalation height are required for protecting human health.

Measurement of atmospheric nanoparticles: Bridging the gap between gas-phase molecules and larger particles

Atmospheric nanoparticles are crucial components contributing to fine particulate matter (PM_2.5), and therefore have significant effects on visibility, climate, and human health. Due to the unique role of atmospheric nanoparticles during the evolution process from gas-phase molecules to larger particles, a number of sophisticated experimental techniques have been developed and employed for online monitoring and characterization of the physical and chemical properties of atmospheric nanoparticles, helping us to better understand the formation and growth of new particles. In this paper, we firstly review these state-of-the-art techniques for investigating the formation and growth of atmospheric nanoparticles (e.g., the gas-phase precursor species, molecular clusters, physicochemical properties, and chemical composition). Secondly, we present findings from recent field studies on the formation and growth of atmospheric nanoparticles, utilizing several advanced techniques. Furthermore, perspectives are proposed for technique development and improvements in measuring atmospheric nanoparticles.

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 AAE_370/520 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 C_nH_2nO₂, C_nH_2n-2O₂, C_nH_2n-4O₂ and C_nH_2n-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.

A review of critical residential buildings parameters and activities when investigating indoor air quality and pollutants

Indoor air in residential dwellings can contain a variety of chemicals, sometimes present at concentrations or in combinations which can have a negative impact on human health. Indoor Air Quality (IAQ) surveys are often required to characterize human exposure or to investigate IAQ concerns and complaints. Such surveys should include sufficient contextual information to elucidate sources, pathways, and the magnitude of exposures. The aim of this review was to investigate and describe the parameters that affect IAQ in residential dwellings: building location, layout, and ventilation, finishing materials, occupant activities, and occupant demography. About 180 peer-reviewed articles, published from 01/2013 to 09/2021 (plus some important earlier publications), were reviewed. The importance of the building parameters largely depends on the study objectives and whether the focus is on a specific pollutant or to assess health risk. When considering classical pollutants such as particulate matter (PM) or volatile organic compounds (VOCs), the building parameters can have a significant impact on IAQ, and detailed information of these parameters needs to be reported in each study. Research gaps and suggestions for the future studies together with recommendation of where measurements should be done are also provided.

Vertically-resolved indoor measurements of air pollution during Chinese cooking

Chinese cooking features several unique processes, e.g., stir-frying and pan-frying, which represent important sources of household air pollution. However, factors affecting household air pollution and the vertical variations of indoor pollutants during Chinese cooking are less clear. Here, using low-cost sensors with high time resolutions, we measured concentrations of five gas species and particulate matter (PM) in three different sizes at multiple heights in a kitchen during eighteen different Chinese cooking events. We found indoor gas species were elevated by 21%-106% during cooking, compared to the background, and PMs were elevated by 44%-159%. Vertically, the pollutants concentrations were highly variable during cooking periods. Gas species generally showed a monotonic increase with height, while PMs changed more diversely depending on the cooking activity's intensity. Intense cooking, e.g., stir-frying, pan-frying, or cooking on high heat, tended to shoot PMs to the upper layers, while moderate ones left PMs within the breathing zone. Individuals with different heights would be subject to different levels of household air pollution exposure during cooking. The high vertical variability challenges the current indoor standard that presumes a uniform pollution level within the breathing zone and thus has important implications for public health and policy making.

Home Energy Upgrades as a Pathway to Home Decarbonization in the US: A Literature Review

This work aims to characterize how home energy upgrade projects and programs in the US have evolved over the past decade. It also identifies what changes are needed to drive expansion of the US energy retrofit market in such a way that addresses carbon emissions from buildings, improves resilience and upgrades the housing stock. This review focuses on whole-home energy upgrades, targeting deep energy retrofit savings of >30%. The topics we cover include trends in home electrification, US and European home energy upgrade programs, energy upgrade measure costs, business economics, and health effects. Key changes in project design noted in this review include: (1) the electrification of dwellings with rapidly improving heat pump systems and low-cost solar photovoltaic technology; and (2) a shift away from high-cost building envelope strategies and towards more traditional home performance/weatherization envelope upgrades. Promising program design strategies covered include: (1) end-use electrification programs; (2) novel financing approaches; (3) the use of carbon-based program and project metrics; and (4) “one-stop shop” programs. Based on the existing market barriers, we suggest that the industry should adopt new project performance metrics. Additionally, market drivers are needed to spur widespread energy upgrades in the US housing stock. Costs must be reduced, and projects designed to appeal to homeowners and contractors.

Short-Term Effects of Low-Level Ambient Air NO2 on the Risk of Incident Stroke in Enshi City, China

Previous studies found that exposure to ambient nitrogen dioxide (NO₂) was associated with an increased risk of incident stroke, but few studies have been conducted for relatively low NO₂ pollution areas. In this study, the short-term effects of NO₂ on the risk of incident stroke in a relatively low-pollution area, Enshi city of Hubei Province, China, were investigated through time-series analysis. Daily air-pollution data, meteorological data, and stroke incidence data of residents in Enshi city from 1 January 2015 to 31 December 2018 were collected. A time-series analysis using a generalised additive model (GAM) based on Poisson distribution was applied to explore the short-term effects of low-level NO₂ exposure on the risk of incident stroke and stroke subtypes, as well as possible age, sex, and seasonal differences behind the effects. In the GAM model, potential confounding factors, such as public holidays, day of the week, long-term trends, and meteorological factors (temperature and relative humidity), were controlled. A total of 9122 stroke incident cases were included during the study period. We found that NO₂ had statistically significant effects on the incidence of stroke and ischemic stroke, estimated by excess risk (ER) of 0.37% (95% CI: 0.04–0.70%) and 0.58% (95% CI: 0.18–0.98%), respectively. For the cumulative lag effects, the NO₂ still had a statistically significant effect on incident ischemic stroke, estimated by ER of 0.61% (95% CI: 0.01–1.21%). The two-pollutant model showed that the effects of NO₂ on incident total stroke were still statistically significant after adjusting for other air pollutants (PM_2.5, PM₁₀, SO₂, CO, and O₃). In addition, the effects of NO₂ exposure on incident stroke were statistically significant in elderly (ER = 0.75%; 95% CI: 0.11–1.40%), males (ER = 0.47%; 95% CI: 0.05–0.89%) and cold season (ER = 0.83%; 95% CI: 0.15–1.51%) subgroups. Our study showed that, as commonly observed in high-pollution areas, short-term exposure to low-level NO₂ was associated with an increased risk of incident stroke, including ischemic stroke. Males and elderly people were more vulnerable to the effects of NO₂, and the adverse effects might be promoted in the cold season.

Exposure of Individuals in Europe to Air Pollution and Related Health Effects

Air pollutants, especially PM2.5 and NO₂, are associated with adverse health impacts, as shown by numerous epidemiological studies. In these studies, the observed health impacts have been correlated with ambient concentrations, mainly taken from air pollution monitoring stations. However, individuals are harmed by the pollutants in the inhaled air at the places where they stay, and thus, the concentration of pollutants in the inhaled air is obviously a better indicator for health impacts than the ambient concentration at a monitoring station. Furthermore, the current method for estimating the occurrence of chronic diseases uses annual average concentrations as indicator. However, according to current hypotheses, chronic diseases, especially chronic mortality, develop through the exposure to pollutants over many years, maybe up to a full lifetime. Thus in this study, a methodology and a computer-aided probabilistic model system are described for calculating the exposure of a person to PM2.5 and NO₂ over the whole lifetime where the person is characterized by attributes such as age, gender, place of residence and work as well as socioeconomic status. The model system contains a “life course trajectory model”, which estimates the course of the education and professional development for the past lifetime of a person, whose present socioeconomic status is known. Furthermore, a “time-activity model” estimates at which places (so-called micro-environments) a person with a certain socioeconomic status stayed and how long he stayed there within a certain year. The concentrations of air pollutants in indoor environments are calculated with a “mass-balance model”, the outdoor concentrations with “atmospheric models”. Finally, the results of these models are combined to estimate the annual average exposure for the life years of individuals and population subgroups. The exposure is then used to estimate and monetize health impacts. The exposures and health impacts for a number of population subgroups in Europe are presented. For instance, a European citizen, who was 70 years old in 2015, has been exposed to around 25 μg/m³ of PM2.5 during his lifetime above the age of 30, which is associated with a reduction of life expectancy of 13.4 days per year of exposure above 30.

Effects of household cooking with clean energy on the risk for hypertension among women in Beijing

Outdoor air pollution and indoor burning of biomass fuel can cause high blood pressure. However, little is known about the effects of cooking with clean energy on hypertension. We thus explored whether cooking with clean energy is associated with the risk for hypertension. The study used baseline data from 12,349 women from a large population-based cohort study in Beijing, China. Information on cooking habits, health status, and other characteristics was collected by questionnaire and physical examination. Fasting blood samples were collected to measure total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and homocysteine (HCY). An index of cooking exposure was constructed. Log-binomial regression models were used to estimate the association between cooking exposure and risk for hypertension. The prevalence of hypertension was 26.7%. Any cooking exposure at all was associated with an increased risk for hypertension with an adjusted prevalence ratio (aPR) of 2.27 (95% confidence interval [CI]: 2.01, 2.57). The risk for hypertension increased with increases in cooking frequency, time spent cooking, and the cooking index, all showing a dose-effect relationship (P < 0.001). An increased risk for hypertension was associated with both cooking using mainly electricity (aPR: 1.75, 95% CI: 1.41, 2.17) and cooking using mainly natural gas (aPR: 2.30, 95% CI: 2.03, 2.60). The cooking index was positively correlated with plasma concentrations of TC, TG, LDL-C, and HCY and negatively correlated with HDL-C. Abnormal levels of all these biomarkers were associated with an increased prevalence of hypertension after adjustment for confounding factors. Cooking with clean energy, mainly cooking habit, may contribute to an increased risk for hypertension among female residents of Beijing. Abnormal metabolism of lipids or HCY may be an important mechanism involved in the development of cooking-related hypertension.

Long-term exposure to ambient nitrogen dioxide and ozone modifies systematic low-grade inflammation: The CHCN-BTH study

The potential effect of long-term exposure to ambient air pollutants on low-grade systematic inflammation has seldom been evaluated taking indoor air pollution and self-protection behaviors on smog days into account. A total of 24,346 participants at baseline were included to conduct a cross-sectional study. The annual (2016) average pollutant concentrations were assessed by air monitoring stations for PM_2.5, PM₁₀, SO₂, NO₂, O₃ and CO. Associations between annual ambient air pollution and low-grade systematic inflammation (hsCRP>3 mg/L) were estimated by generalized linear mixed models. Stratification analysis was also performed based on demographic characteristics, health-related behaviors and disease status. Annual ambient NO₂ and O₃ were all associated with low-grade systematic inflammation in single-pollutant models after adjusting for age, sex, blood lipids, blood pressure, lifestyle risk factors, cooking fuel, heating fuel and habits during smog days (NO₂ per 10 μg/m³: OR = 1.057, P = 0.018; O₃ per 10 μg/m³: OR = 0.953, P = 0.012). The 2-year and 3-year ozone concentrations were consistently associated with lower systematic inflammation (2-year O₃ per 10 μg/m³: OR = 0.959, P = 0.004; 3-year O₃ per 10 μg/m³: OR = 0.961, P = 0.014). In two-pollutant models, the estimated effects of annual NO₂ and O₃ on low-grade systematic inflammation remained stable. The effect size of annual pollutants on inflammation increased in participants without air-purifier usage (NO₂ per 10 μg/m³: OR = 1.079, P = 0.009; O₃ per 10 μg/m³: OR = 0.925, P = 0.001), while the association was null in the air-purifier usage group. Thus, long-term exposure to ambient NO₂ and O₃ was associated with low-grade systemic inflammation, and the results were generally stable after sensitivity analysis. The usage of air purifiers on smog days can modify the association between gaseous pollutants and systematic inflammation.

Indoor Particulate Matter in Urban Households: Sources, Pathways, Characteristics, Health Effects, and Exposure Mitigation

Particulate matter (PM) is a complex mixture of solid particles and liquid droplets suspended in the air with varying size, shape, and chemical composition which intensifies significant concern due to severe health effects. Based on the well-established human health effects of outdoor PM, health-based standards for outdoor air have been promoted (e.g., the National Ambient Air Quality Standards formulated by the U.S.). Due to the exchange of indoor and outdoor air, the chemical composition of indoor particulate matter is related to the sources and components of outdoor PM. However, PM in the indoor environment has the potential to exceed outdoor PM levels. Indoor PM includes particles of outdoor origin that drift indoors and particles that originate from indoor activities, which include cooking, fireplaces, smoking, fuel combustion for heating, human activities, and burning incense. Indoor PM can be enriched with inorganic and organic contaminants, including toxic heavy metals and carcinogenic volatile organic compounds. As a potential health hazard, indoor exposure to PM has received increased attention in recent years because people spend most of their time indoors. In addition, as the quantity, quality, and scope of the research have expanded, it is necessary to conduct a systematic review of indoor PM. This review discusses the sources, pathways, characteristics, health effects, and exposure mitigation of indoor PM. Practical solutions and steps to reduce exposure to indoor PM are also discussed.

Indoor unclean fuel cessation linked with adult cognitive performance in China

Both indoor unclean fuel use and CVD associates with cognitive function. Indoor fuel has transitioned from the use of unclean fuel to clean fuel in recent years in China. The aim of this study was to evaluate the association between adult cognitive function and such a transition and to investigate the potential role of CVD in this association. 7112 participants (26- to 98-years of age) with 12,676 observations living in twelve provinces of China from 1997 to 2015 were extracted based on having complete data. The associations, combined effects, and further mediation effects between indoor unclean fuel use and its transition, CVD, and cognitive function were tested using regression models, stratified analyses, the relative excess risk due to interaction (RERI), mediation analysis methods, and sensitivity analyses. Between 1997 and 2015, cooking fuel use coal and wood went down a lot in China, from a baseline of 26.9% to 6.1%, from 30.1% to 11.5%, respectively. Such a transition showed a positive association with delayed verbal recall (B = 0.288, p < 0.01), especially in rural area, subjects with age ≥ 65 years old, and women (all P < 0.05). The combined effect of the presence of hypertension during a baseline visit and such a transition on changes in delayed verbal recall was antagonistic (RERI = -0.529, p < 0.05). Moreover, the development of hypertension explained more than 50% of such a fuel transition-related decline of verbal memory. The transition of household energy to clean fuel was associated with a higher adult cognitive function. The presence or the development of CVD appeared to affect the association between indoor air pollution and cognitive function, which suggests a need to further optimize prevention of concurrent CVD and risk factor control in adults at higher risk for cognitive impairment and with indoor unclean cooking fuel, especially in potentially susceptible subgroups.

The impact of second-hand smoke on nitrogen oxides concentrations in a small interior

Nitrogen oxides (NO_x), especially nitrogen dioxide (NO₂), are among the most hazardous forms of air pollution. Tobacco smoke is a main indoor source of NO_x, but little information is available about their concentrations in second-hand smoke (SHS), particularly in small indoors. This study presents data of NO_x and its main components nitric oxide (NO) and NO₂ in SHS emitted by ten different cigarette brands measured in a closed test chamber with a volume of 2.88 m³, similar to the volume of vehicle cabins. The results show substantial increases in NO_x concentrations when smoking only one cigarette. The NO₂ mean concentrations ranged between 105 and 293 µg/m³, the NO₂ peak concentrations between 126 and 357 µg/m³. That means the one-hour mean guideline of 200 µg/m³ for NO₂ of the World Health Organization was exceeded up to 47%, respectively 79%. The measured NO₂ values show positive correlations with the values for tar, nicotine, and carbon monoxide stated by the cigarette manufacturers. This study provides NO₂ concentrations in SHS at health hazard levels. These data give rise to the necessity of health authorities' measures to inform about and caution against NO_x exposure by smoking in indoor rooms.

Temporal and spatial variation of PM2.5 in indoor air monitored by low-cost sensors

Indoor air pollution has significant adverse health impacts, but its spatiotemporal variations and source contributions are not well quantified. In this study, we used low-cost sensors to measure PM_2.5 concentrations in a typical apartment in Beijing. The measurements were conducted at 15 indoor sites and one outdoor site on 1-minute temporal resolution (convert to 10-minute averages for data analysis) from March 14 to 24, 2020. Based on these highly spatially-and temporally-resolved data, we characterized spatiotemporal variations and source contributions of indoor PM_2.5 in this apartment. It was found that indoor particulate matter predominantly originates from outdoor infiltration and cooking emissions with the latter contributing more fine particles. Indoor PM_2.5 concentrations were found to be correlated with ambient levels but were generally lower than those outdoors with an average I/O of 0.85. The predominant indoor source was cooking, leading to occasional high spikes. The variations observed in most rooms lagged behind those measured outdoors and in the studied kitchen. Differences between rooms were found to depend on pathway distances from sources. On average, outdoor sources contributed 36% of indoor PM_2.5, varying extensively over time and among rooms. From observed PM_2.5 concentrations at the indoor sites, source strengths, and pathway distances, a multivariate regression model was developed to predict spatiotemporal variations of PM_2.5. The model explains 79% of the observed variation and can be used to dynamically simulate PM_2.5 concentrations at any site indoors. The model's simplicity suggests the potential for regional-scale application for indoor air quality modeling.

The Effect of Residential Environment on Respiratory Diseases and Pulmonary Function in Children from a Community in Jilin Province of China

Purpose

Respiratory disease is a major and increasingly global epidemic that has a great impact on humans, especially children. The purpose of this study was to identify environmental risk factors for respiratory diseases and pulmonary function in children.

Patients and Methods

A population-based, cross-sectional survey of respiratory diseases and environmental risk factors was conducted in Jilin Province, China. Complete questionnaire information was available for 2419 children, while adequate pulmonary function data were available for a subgroup of 627 children.

Results

Our study found that environmental risk factors for respiratory health in children were mainly concentrated indoors. After adjusting for demographic factors, insecticide exposure and passive smoking were risk factors for respiratory disease and industrial pollutant sources, insecticide exposure and the use of a fume exhauster may be independent risk factors for recurrent respiratory infections. The main fuel for cooking in the winter and passive smoking were the main influencing factors of pulmonary function indicators.

Conclusion

The primary risk factors differ in different respiratory diseases. Passive smoking remains a critical adverse factor for respiratory illness and pulmonary function in children, and it is important to reduce children’s exposure to passive smoking to increase pulmonary health. Insecticide exposure may be a neglected environmental risk factor, and further investigations are still needed to explore the relationship and mechanisms between insecticide exposure and children’s respiratory health.

Loss of NO(g) to painted surfaces and its re-emission with indoor illumination

Heterogeneous surface reactions play a key role in the chemistry of the indoor environment because of the large indoor surface-to-volume ratio. The presence of photocatalytic material in indoor paints may allow photochemical reactions to occur at wavelengths of light that are present indoors. One such potential reaction is the heterogeneous photooxidation of NO to HONO. NO(g) is commonly found indoors, originating from combustion sources, ventilation and infiltration of outdoor air. We studied the interaction of NO(g) with painted surfaces illuminated with indoor fluorescent and incandescent lighting. There is a loss of NO(g) to painted surfaces in the dark at both 0 and 50% RH. At 50% RH, there is a re-release of some of that NO(g) under illumination. The same behavior is observed for illumination of different colored paints. This is in contrast to what is seen with TiO₂ as the substrate, where photoenhanced uptake of NO(g) and formation of NO₂ (g) are observed. We hypothesize that the loss of NO(g) is due to adsorption and diffusion into the paint. The re-release of NO under illumination is thought to be due to photooxidation of NO to HONO on the painted surface at higher relative humidities and subsequent HONO photolysis.

Spatio-Temporal Representativeness of Air Quality Monitoring Stations in Mexico City: Implications for Public Health

Assessment of the air quality in metropolitan areas is a major challenge in environmental sciences. Issues related include the distribution of monitoring stations, their spatial range, or missing information. In Mexico City, stations have been located spanning the entire Metropolitan zone for pollutants, such as CO, NO2, O3, SO2, PM2.5, PM10, NO, NO x , and PM CO . A fundamental question is whether the number and location of such stations are adequate to optimally cover the city. By analyzing spatio-temporal correlations for pollutant measurements, we evaluated the distribution and performance of monitoring stations in Mexico City from 2009 to 2018. Based on our analysis, air quality evaluation of those contaminants is adequate to cover the 16 boroughs of Mexico City, with the exception of SO2, since its spatial range is shorter than the one needed to cover the whole surface of the city. We observed that NO and NO x concentrations must be taken into account since their long-range dispersion may have relevant consequences for public health. With this approach, we may be able to propose policy based on systematic criteria to locate new monitoring stations.

Links between air pollution and COVID-19 in England

In December 2019, a novel disease, coronavirus disease 19 (COVID-19), emerged in Wuhan, People's Republic of China. COVID-19 is caused by a novel coronavirus (SARS-CoV-2) presumed to have jumped species from another mammal to humans. This virus has caused a rapidly spreading global pandemic. To date, over 300,000 cases of COVID-19 have been reported in England and over 40,000 patients have died. While progress has been achieved in managing this disease, the factors in addition to age that affect the severity and mortality of COVID-19 have not been clearly identified. Recent studies of COVID-19 in several countries identified links between air pollution and death rates. Here, we explored potential links between major fossil fuel-related air pollutants and SARS-CoV-2 mortality in England. We compared current SARS-CoV-2 cases and deaths from public databases to both regional and subregional air pollution data monitored at multiple sites across England. After controlling for population density, age and median income, we show positive relationships between air pollutant concentrations, particularly nitrogen oxides, and COVID-19 mortality and infectivity. Using detailed UK Biobank data, we further show that PM_2.5 was a major contributor to COVID-19 cases in England, as an increase of 1 m³ in the long-term average of PM_2.5 was associated with a 12% increase in COVID-19 cases. The relationship between air pollution and COVID-19 withstands variations in the temporal scale of assessments (single-year vs 5-year average) and remains significant after adjusting for socioeconomic, demographic and health-related variables. We conclude that a small increase in air pollution leads to a large increase in the COVID-19 infectivity and mortality rate in England. This study provides a framework to guide both health and emissions policies in countries affected by this pandemic.

The impact on heart rate and blood pressure following exposure to ultrafine particles from cooking using an electric stove

Cooking is a major source of indoor particulate matter (PM), especially ultrafine particles (UFPs). Long-term exposure to fine and ultrafine particles (UFPs) has been associated with adverse human health effects. Toxicological studies have demonstrated that exposure to PM_2.5 (particles with aerodynamic diameter smaller than 2.5 μm) may result in increased blood pressure (BP). Some clinical studies have shown that acute exposure to PM_2.5 causes changes in systolic (SBP) and diastolic blood pressure (DBP), depending on the source of particles. Studies assessing the effect of exposure to cooking PM on BP and heart rate (HR) using electric or gas stoves are not well represented in the literature. The aim of this investigation was to perform controlled studies to quantify the exposure of 50 healthy volunteer participants to fine and ultrafine particles emitted from a low-emissions recipe for frying ground beef on an electric stove. The BP and heart rate (HR) of the volunteers were monitored during exposure and after the exposure (2 h post-exposure). Maximum UFP and PM_2.5 concentrations were 6.5 × 10⁴ particles/cm³ and 0.017 mg/m³, respectively. Exposure to UFPs from frying was associated with statistically significant increases in the SBP. The lack of food and drink during the 2 h post-cooking period was also associated with a statistically significant reduction in SBP. No statistically significant changes in DBP were observed. Physiological factors, including heat stress over the stove, movements and anxiety, could be responsible for an elevation in HR at the early stages of the experiments with a subsequent drop in HR after 90 min post-cooking, when study participants were relaxed in a living room.

Factors Impacting Range Hood Use in California Houses and Low-Income Apartments

Venting range hoods can control indoor air pollutants emitted during residential cooktop and oven cooking. To quantify their potential benefits, it is important to know how frequently and under what conditions range hoods are operated during cooking. We analyzed data from 54 single family houses and 17 low-income apartments in California in which cooking activities, range hood use, and fine particulate matter (PM2.5) were monitored for one week per home. Range hoods were used for 36% of cooking events in houses and 28% in apartments. The frequency of hood use increased with cooking frequency across homes. In both houses and apartments, the likelihood of hood use during a cooking event increased with the duration of cooktop burner use, but not with the duration of oven use. Actual hood use rates were higher in the homes of participants who self-reported more frequent use in a pre-study survey, but actual use was far lower than self-reported frequency. Residents in single family houses used range hoods more often when cooking caused a discernible increase in PM2.5. In apartments, residents used their range hood more often only when high concentrations of PM2.5 were generated during cooking.

Novel Materials for Combined Nitrogen Dioxide and Formaldehyde Pollution Control under Ambient Conditions

Formaldehyde (HCHO) and nitrogen dioxide (NO2) often co-exist in urban environments at levels that are hazardous to health. There is a demand for a solution to the problem of their combined removal. In this paper, we investigate catalysts, adsorbents and composites for their removal efficiency (RE) toward HCHO and NO2, in the context of creating a pollution control device (PCD). Proton-transfer-reaction mass spectrometry and cavity ring-down spectrometry are used to measure HCHO, and chemiluminescence and absorbance-based monitors for NO2. Commercially available and lab-synthesized materials are tested under relevant conditions. None of the commercial adsorbents are effective for HCHO removal, whereas two metal oxide-based catalysts are highly effective, with REs of 81 ± 4% and 82 ± 1%, an improvement on previous materials tested under similar conditions. The best performing material for combined removal is a novel composite consisting of a noble metal catalyst supported on a metal oxide, combined with a treated active carbon adsorbent. The composite is theorized to work synergistically to physisorb and oxidize HCHO and chemisorb NO2. It has an HCHO RE of 72 ± 2% and an NO2 RE of 96 ± 2%. This material has potential as the active component in PCDs used to reduce personal pollution exposure.

Characterization and pro-inflammatory potential of indoor mold particles

A number of epidemiological studies find an association between indoor air dampness and respiratory health effects. This is often suggested to be linked to enhanced mold growth. However, the role of mold is obviously difficult to disentangle from other dampness-related exposure including microbes as well as non-biological particles and chemical pollutants. The association may partly be due to visible mycelial growth and a characteristic musty smell of mold. Thus, the potential role of mold exposure should be further explored by evaluating information from experimental studies elucidating possible mechanistic links. Such studies show that exposure to spores and hyphal fragments may act as allergens and pro-inflammatory mediators and that they may damage airways by the production of toxins, enzymes, and volatile organic compounds. In the present review, we hypothesize that continuous exposure to mold particles may result in chronic low-grade pro-inflammatory responses contributing to respiratory diseases. We summarize some of the main methods for detection and characterization of fungal aerosols and highlight in vitro research elucidating how molds may induce toxicity and pro-inflammatory reactions in human cell models relevant for airway exposure. Data suggest that the fraction of fungal hyphal fragments in indoor air is much higher than that of airborne spores, and the hyphal fragments often have a higher pro-inflammatory potential. Thus, hyphal fragments of prevalent mold species with strong pro-inflammatory potential may be particularly relevant candidates for respiratory diseases associated with damp/mold-contaminated indoor air. Future studies linking of indoor air dampness with health effects should assess the toxicity and pro-inflammatory potential of indoor air particulate matter and combined this information with a better characterization of biological components including hyphal fragments from both pathogenic and non-pathogenic mold species. Such studies may increase our understanding of the potential role of mold exposure.

Coumarin Derivatives as New Toxic Compounds to Selected K12, R1-R4 E. coli Strains

Coumarins are natural compounds that were detected in 80 species of plants. They have numerous applications including the medical, food, tobacco, perfumery, and spirit industries. They show anti-swelling and diastolic effects. However, excess consumption of coumarins may adversely affect our health, because they are easily absorbed from the intestines into the lymph and blood, causing cirrhosis of the liver. Peptidomimetics are molecules whose structure and function are similar to those of peptides. They are an important group of compounds with biological, microbiological, anti-inflammatory, and anti-cancer properties. Therefore, studies on new peptidomimetics, which load the effect of native peptides, whose half-life in the body is much longer due to structural modifications, are extremely important. A preliminary study of coumarin analogues and its derivatives as new potential antimicrobial drugs containing carboxylic acid or ester was performed to determine their basic structure related to their biological features against various types of Gram-stained bacteria by lipopolysaccharide (LPS). We hypothesized that the toxicity (antibacterial activity) of coumarin derivatives is dependent on the of LPS in bacteria and nature and position of the substituent which may be carboxylic acid, hydroxyl groups, or esters. In order to verify this hypothesis, we used K12 (smooth) and R1–R4 (rough) Escherichia coli strains which are characterized by differences in the type of LPS, especially in the O-antigen region, the outermost LPS layer. In our work, we synthesized 17 peptidomimetics containing a coumarin scaffold and checked their influence on K12 and R1–R4 E. coli strains possessing smooth and rough LPS. We also measured the damage of plasmid DNA caused by target compounds. The results of our studies clearly support the conclusion that coumarin peptidomimetics are antagonistic compounds to many of the currently used antibiotics. The high biological activity of the selected coumarin peptidomimetic was associated with identification of the so-called magic methyl groups, which substantially change the biochemical properties of target compounds. Investigating the effects of these compounds is particularly important in the era of increasingly common resistance in bacteria.

Indoor Air Pollution, Related Human Diseases, and Recent Trends in the Control and Improvement of Indoor Air Quality

Indoor air pollution (IAP) is a serious threat to human health, causing millions of deaths each year. A plethora of pollutants can result in IAP; therefore, it is very important to identify their main sources and concentrations and to devise strategies for the control and enhancement of indoor air quality (IAQ). Herein, we provide a critical review and evaluation of the major sources of major pollutant emissions, their health effects, and issues related to IAP-based illnesses, including sick building syndrome (SBS) and building-related illness (BRI). In addition, the strategies and approaches for control and reduction of pollutant concentrations are pointed out, and the recent trends in efforts to resolve and improve IAQ, with their respective advantages and potentials, are summarized. It is predicted that the development of novel materials for sensors, IAQ-monitoring systems, and smart homes is a promising strategy for control and enhancement of IAQ in the future.

Evaluation of the effectiveness of a portable air cleaner in mitigating indoor human exposure to cooking-derived airborne particles

Gas cooking is an important source of airborne particulate matter (PM) indoors. Exposure to cooking-derived PM can lead to adverse human health impacts on non-smokers, especially in poorly-ventilated residential homes. Most of the previous studies on gas cooking emissions mainly focused on fine particles (PM_2.5) with little information on their size-fractionation. Moreover, studies dealing with mitigation of indoor human exposure to cooking-derived PM are currently sparse. Therefore, a systematic study was conducted to investigate the characteristics of PM_2.5 and size-fractionated PM derived from five commonly used cooking methods, namely, steaming, boiling, stir-frying, pan-frying and deep-frying in a poorly-ventilated domestic kitchen under controlled experimental conditions. Additionally, an indoor portable air cleaner was employed as a mitigation device to capture cooking-derived PM and improve indoor air quality (IAQ). Results revealed that the oil-based deep-frying cooking released the highest airborne particles which were about 170 folds higher compared to the baseline levels for PM_2.5 mass concentrations. The use of the air cleaner showed a statistically significant (p < 0.05) reduction in the indoor PM_2.5 levels. Moreover, PM_<0.25 (particles with diameter ≤ 250 nm) showed a very high mass concentration (378.2 μg/m³) during deep-frying, raising human health concern. A substantial reduction (~60-85%) in PM_<0.25 mass concentrations and their total respiratory deposition doses (RDD) in the human respiratory tract was observed while using the air cleaner during the five cooking methods. Furthermore, morphological characteristics and the relative abundance of trace elements in cooking-derived PM were also investigated. This study provides useful insights into the assessment and mitigation of indoor human exposure to cooking-derived PM.

Cooking fuels and risk of all-cause and cardiopulmonary mortality in urban China: a prospective cohort study

BACKGROUND

Cooking practice has transitioned from use of solid fuels to use of clean fuels, with addition of better ventilation facilities. However, the change in mortality risk associated with such a transition remains unclear.

METHODS

The China Kadoorie Biobank (CKB) Study enrolled participants (aged 30-79 years) from ten areas across China; we chose to study participants from five urban areas where transition from use of solid fuels to clean fuels for cooking was prevalent. Participants who reported regular cooking (weekly or more frequently) at baseline were categorised as persistent clean fuel users, previous solid fuel users, or persistent solid fuel users, according to self-reported fuel use histories. All-cause and cardiopulmonary mortality were identified through linkage to China's Disease Surveillance Point system and local mortality records.

FINDINGS

Between June 24, 2004, and July 15, 2008, 226 186 participants living in five urban areas of China were enrolled in the CKB Study. Among 171 677 participants who reported cooking regularly (weekly or more frequently), 75 785 (44%) were persistent clean fuel users, 80 511 (47%) were previous solid fuel users, and 15 381 (9%) were persistent solid fuel users. During a mean of 9·8 (SD 1·7) years of follow-up, 10 831 deaths were documented, including 3819 cardiovascular deaths and 761 respiratory deaths. Compared with persistent clean fuel users, persistent solid fuel users had significantly higher risks of all-cause mortality (hazard ratio [HR] 1·19, 95% CI 1·10-1·28), cardiovascular mortality (1·24, 1·10-1·39), and respiratory mortality (1·43, 1·10-1·85). The excess risk of all-cause and cardiopulmonary mortality fell by more than 60% in 5 years after cessation of solid fuel use and continued to decrease afterwards. Use of ventilation was associated with lower all-cause mortality risk, even among persistent clean fuel users (HR 0·78, 0·69-0·89).

INTERPRETATION

Solid fuel use for cooking is associated with a higher risk of mortality, and cessation of solid fuel use cuts excess mortality risks swiftly and substantially within 5 years. Ventilation use also lowers the risk of mortality, even among people who persistently use clean fuels. It is of prime importance for both policy makers and the public to accelerate the transition from solid fuels to clean fuels and promote efficient ventilation to minimise further adverse health effects.

FUNDING

National Natural Science Foundation of China, Wellcome Trust, and Kadoorie Charitable Foundation.

Cooking fuels and risk of all-cause and cardiopulmonary mortality in urban China: a prospective cohort study

BACKGROUND

Cooking practice has transitioned from use of solid fuels to use of clean fuels, with addition of better ventilation facilities. However, the change in mortality risk associated with such a transition remains unclear.

METHODS

The China Kadoorie Biobank (CKB) Study enrolled participants (aged 30-79 years) from ten areas across China; we chose to study participants from five urban areas where transition from use of solid fuels to clean fuels for cooking was prevalent. Participants who reported regular cooking (weekly or more frequently) at baseline were categorised as persistent clean fuel users, previous solid fuel users, or persistent solid fuel users, according to self-reported fuel use histories. All-cause and cardiopulmonary mortality were identified through linkage to China's Disease Surveillance Point system and local mortality records.

FINDINGS

Between June 24, 2004, and July 15, 2008, 226 186 participants living in five urban areas of China were enrolled in the CKB Study. Among 171 677 participants who reported cooking regularly (weekly or more frequently), 75 785 (44%) were persistent clean fuel users, 80 511 (47%) were previous solid fuel users, and 15 381 (9%) were persistent solid fuel users. During a mean of 9·8 (SD 1·7) years of follow-up, 10 831 deaths were documented, including 3819 cardiovascular deaths and 761 respiratory deaths. Compared with persistent clean fuel users, persistent solid fuel users had significantly higher risks of all-cause mortality (hazard ratio [HR] 1·19, 95% CI 1·10-1·28), cardiovascular mortality (1·24, 1·10-1·39), and respiratory mortality (1·43, 1·10-1·85). The excess risk of all-cause and cardiopulmonary mortality fell by more than 60% in 5 years after cessation of solid fuel use and continued to decrease afterwards. Use of ventilation was associated with lower all-cause mortality risk, even among persistent clean fuel users (HR 0·78, 0·69-0·89).

INTERPRETATION

Solid fuel use for cooking is associated with a higher risk of mortality, and cessation of solid fuel use cuts excess mortality risks swiftly and substantially within 5 years. Ventilation use also lowers the risk of mortality, even among people who persistently use clean fuels. It is of prime importance for both policy makers and the public to accelerate the transition from solid fuels to clean fuels and promote efficient ventilation to minimise further adverse health effects.

FUNDING

National Natural Science Foundation of China, Wellcome Trust, and Kadoorie Charitable Foundation.

Non-allergic rhinitis and associated risk factors among the elderly in communities close to gold mine dumps in Gauteng and North West provinces in South Africa: a cross-sectional study

PURPOSE

To investigate whether non-allergic rhinitis among the elderly was associated with living close to mine dumps METHODS: Elderly persons (n = 2397) residing in communities 1-2 km (exposed) and ≥ 5 km (unexposed) from five preselected mine dumps in Gauteng and North West provinces in South Africa were included in the cross-sectional study, using a previously validated modified ATS-DLD-78 questionnaire from the British Medical Research Council.

RESULTS

The overall prevalence of non-allergic rhinitis in this study was 23.99%. In the unexposed, it was found to be 18.82% and 27.08% exposed communities. Multiple logistic regression analysis indicated that having non-allergic rhinitis was significantly associated with living in exposed communities (OR 1.73; 95% CI 1.37-2.17), being an ex-smoker (OR 1.75; 95 CI 1.35-2.26), being a smoker (OR 1.24; 95% CI 1.02-1.62), history of occupational exposure to dust/chemical fumes (OR 1.58; 1.30-1.93) and use of gas as the main residential heating/cooking fuel type (OR 1.61; 1.01-2.57).

CONCLUSION

A high prevalence of non-allergic rhinitis was observed in the elderly living in exposed communities. The adverse association was observed between residing in communities close to mine dumps and non-allergic rhinitis.

Dynamic behavior of indoor ultrafine particles (2.3-64 nm) due to burning candles in a residence

A major source of human exposure to ultrafine particles is candle use. Candles produce ultrafine particles in the size range under 10 nm, with perhaps half of the particles less than 5 nm. For these small particles at typically high concentrations, coagulation and deposition are two dominant mechanisms in aerosol size dynamics. We present an updated coagulation model capable of characterizing the relative contributions of coagulation, deposition, and air exchange rates. Size-resolved coagulation and decay rates are estimated for three types of candles. Number, area, and mass distributions are provided for 93 particle sizes from 2.33 to 64 nm. Total particle production was in the range of 10¹³  min^-1 . Peak number, area, and mass concentrations occurred at particle sizes of <3, 20, and 40 nm, respectively. Both the number and area concentrations greatly exceeded background concentrations in the residence studied. Contributions of coagulation, deposition, and air exchange rates to particle losses were 65%, 34%, and 0.3% at high concentrations (10⁶  cm^-3 ), while they are 17%, 81%, and 1.7% at lower concentrations (3 × 10⁴  cm^-3 ), respectively. The increased particle production for the very smallest particles (2.33-2.50 nm) suggests that even smaller particles may be important to study.

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

Cooking is recognized as an important source of particulate pollution in indoor and outdoor environments. We conducted more than 100 individual experiments to characterize the particulate and non-methane organic gas emissions from various cooking processes, their reaction rates, and their secondary organic aerosol yields. We used this emission data to develop a box model, for simulating the cooking emission concentrations in a typical European home and the indoor gas-phase reactions leading to secondary organic aerosol production. Our results suggest that about half of the indoor primary organic aerosol emission rates can be explained by cooking. Emission rates of larger and unsaturated aldehydes likely are dominated by cooking while the emission rates of terpenes are negligible. We found that cooking dominates the particulate and gas-phase air pollution in non-smoking European households exceeding 1000 μg m-3 . While frying processes are the main driver of aldehyde emissions, terpenes are mostly emitted due to the use of condiments. The secondary aerosol production is negligible with around 2 μg m-3 . Our results further show that ambient cooking organic aerosol concentrations can only be explained by super-polluters like restaurants. The model offers a comprehensive framework for identifying the main parameters controlling indoor gas- and particle-phase concentrations.

Association between prenatal exposure to household inhalants exposure and ADHD-like behaviors at around 3 years of age: Findings from Shenzhen Longhua Child Cohort Study

BACKGROUND

Prenatal exposure to air pollutants has been suggested as a possible etiologic factor for the occurrence of ADHD or ADHD-like behaviors. But we still lack a comprehensive assessment of household air pollutants exposure on the development of ADHD-like behaviors during childhood.

OBJECT

We aimed to assess whether prenatal household inhalants exposure is associated with preschoolers' ADHD-like behaviors in a nonclinical population.

METHODS

This study used the baseline data of the Longhua Child Cohort Study. During 2015-2017, we recruited 42,983 mothers and their kindergarten-aged children who enrolled at kindergarten in the Longhua district of Shenzhen, to obtain the demographic data and relevant exposure information through self-administrated questionnaire survey. The source of prenatal household inhalants exposure include cooking fumes, environmental tobacco smoke, mosqutio coils, home renovated and indoor burning incense. Logistic and censored least absolute deviations (CLAD) models were used to reveal the association between prenatal exposure to household air pollutants and hyperactive behaviors in child.

RESULTS

We found that exposure to five types of household inhalants during pregnancy were independently associated with an increased risk of child hyperactive behaviors. Moreover, we observed a significant interaction between exposure to environmental tobacco smoke and cooking fumes during gestation on child hyperactive behaviors in CLAD models. We also found a significant joint effect between burning mosquito coils and incense during gestation for child hyperactive behaviors risk both in CLAD and Logistic models. Furthermore, a household inhalants exposure index was used to demonstrate a dose-response relationship between the cumulative effect of exposure to the five household air pollutants and child hyperactivity.

CONCLUSIONS

Our results suggest that prenatal exposure to different household inhalants might increase the risk of children's hyperactive behaviors at around 3 years of age with the presence of interaction effects between some inhalants.

Investigating measurements of fine particle (PM2.5 ) emissions from the cooking of meals and mitigating exposure using a cooker hood

There is growing awareness that indoor exposure to particulate matter with diameter ≤ 2.5 μm (PM_2.5 ) is associated with an increased risk of adverse health effects. Cooking is a key indoor source of PM_2.5 and an activity conducted daily in most homes. Population scale models can predict occupant exposures to PM_2.5 , but these predictions are sensitive to the emission rates used. Reported emission rates are highly variable and are typically for the cooking of single ingredients and not full meals. Accordingly, there is a need to assess PM_2.5 emissions from the cooking of complete meals. Mean PM_2.5 emission rates and source strengths were measured for four complete meals. Temporal PM_2.5 concentrations and particle size distributions were recorded using an optical particle counter (OPC), and gravimetric sampling was used to determine calibration factors. Mean emission rates and source strengths varied between 0.54-3.7 mg/min and 15-68 mg, respectively, with 95% confidence. Using a cooker hood (apparent capture efficiency > 90%) and frying in non-stick pans were found to significantly reduce emissions. OPC calibration factors varied between 1.5 and 5.0 showing that a single value cannot be used for all meals and that gravimetric sampling is necessary when measuring PM_2.5 concentrations in kitchens.

Siloxane in baking moulds, emission to indoor air and migration to food during baking with an electric oven

Linear and cyclic volatile methylsiloxanes (l-VMS and c-VMS) are man-made chemicals with no natural source. They have been widely used in cosmetics, personal care products, coatings and many other products. As a consequence of their wide use, VMS can be found in different environmental media, as well as in humans. We bought 14 new silicone baking moulds and 3 metallic moulds from the market and used them in different baking experiments. Four of the silicone baking moulds were produced in Germany, two in Italy, four in China, and for the other moulds were no information available. The metal forms were all produced in Germany. VMS were measured in the indoor air throughout the baking process and at the edge and in the center of the finished cakes using a GC/MS system. Additionally, the particle number concentration (PNC) and particle size distribution were measured in the indoor air. The highest median concentrations of VMS were observed immediately following baking: 301 μg/m³ of D7, 212 μg/m³ of D6, and 130 μg/m³ of D8. The silicone moulds containing the highest concentrations of c-VMS corresponded with distinctly higher concentrations of the compounds in indoor air. Using a mould for more than one baking cycle reduced the indoor air concentrations substantially. Samples collected from the edge of the cake had higher concentrations relative to samples from the center, with a mean initial concentration of 6.6 mg/kg of D15, 3.9 mg/kg of D9, 3.7 mg/kg of D12, and 4.8 mg/kg of D18. D3 to D5 were measured only at very low concentrations. Before starting the experiment, an average PNC of 7300 particles/cm³ was observed in the room's air, while a PNC of 140,000 particles/cm³ was observed around the electric stove while it was baking, but this PNC slowly decreased after the oven was switched off. Baking with 4 of the moulds exceeded the German indoor precaution guide value for c-VMS, but the health hazard guide value was not reached during every experiment. Compared to other exposure routes, c-VMS contamination of cake from silicone moulds seems to be low, as demonstrated by the low concentrations of D4 and D6 measured. For less volatile c-VMS > D6 the results of the study indicate that food might play a more important role for daily intake. As a general rule, silicone moulds should be used only after precleaning and while strictly following the temperature suggestions of the producers.

Determination of the emission rate for ultrafine and accumulation mode particles as a function of time during the pan-frying of fish

Particulate matter (PM) from cooking is considered one of the most harmful indoor air pollutants causing numerous adverse health effects, and it is essential to comprehend the characteristics of the particles generated from cooking to prevent these problems. In this study, we investigated PM from the pan-frying of salmon using number concentration and developed emission rates as a function of time for ultrafine particles (UFPs < 100 nm) and accumulation mode particles (AMPs 0.1-1 μm). The newly defined emission rates vary significantly with time and are very different from the conventionally determined rates that do not consider the variation of particle concentration with time. The emission rate of UFPs decreased over time after a sharp rise, whereas that of AMPs continued to increase, resulting in a change in the proportions of UFPs and AMPs in the total PM from 93 to 7% to 72 and 28%, respectively. Particle-particle interactions such as coagulation and coalescence were observed between primary particles via high resolution transmission electron microscopy (HR-TEM), which is a plausible reason for the decreasing emission rate of UFPs with time. The emission rate as a function of time can serve as a tool to estimate PM from cooking, as well as to monitor the change trends through phenomena such as agglomeration.

Development of an in-home, real-time air pollutant sensor platform and implications for community use

Air pollution exposure characterization has been shaped by many constraints. These include technologies that lead to insufficient coverage across space and/or time in order to characterize individual or community-level exposures with sufficient accuracy and precision. However, there is now capacity for continuous monitoring of many air pollutants using comparatively inexpensive, real-time sensors. Crucial questions remain regarding whether or not these sensors perform adequately for various potential end uses and whether performance varies over time or across ambient conditions. Performance scrutiny of sensors via lab- and field-testing and calibration across their lifetime is necessary for interpretation of data, and has important implications for end users including cost effectiveness and ease of use. We developed a comparatively lower-cost, portable, in-home air sampling platform and a guiding development and maintenance workflow that achieved our goal of characterizing some key indoor pollutants with high sensitivity and reasonable accuracy. Here we describe the process of selecting, validating, calibrating, and maintaining our platform - the Environmental Multi-pollutant Monitoring Assembly (EMMA) - over the course of our study to-date. We highlight necessary resources and consider implications for communities or researchers interested in developing such platforms, focusing on PM_2.5, NO, and NO₂ sensors. Our findings emphasize that lower-cost sensors should be deployed with caution, given financial and resource costs that greatly exceed sensor costs, but that selected community objectives could be supported at lesser cost and community-based participatory research strategies could be used for more wide-ranging goals.

Ultrafine Particle Emissions from Natural Gas, Biogas, and Biomethane Combustion

Biogas and biomethane (=purified biogas) are major renewable fuels that play a pivotal role in the evolving global energy economy. Here, we measure ultrafine particle (UFP; D_p (particle diameter) < 100 nm) emissions from the combustion of biomethane and biogas produced from five different representative sources: two food waste digesters, two dairy waste digesters, and one landfill. Combustion exhaust for each of these sources is measured from one or more representative sectors including electricity generation, motor vehicles, and household use. Results show that UFP emissions are similar when using biomethane and natural gas with similar sulfur and siloxane content. Approximately 70% of UFPs emitted from water heaters and cooking stoves were semivolatile, but 30% of the UFPs were nonvolatile and did not evaporate even under extremely high dilution conditions. Photochemical aging of biomethane combustion exhaust and natural gas combustion exhaust produced similar amounts of secondary organic aerosol (SOA) formation. The results of the current study suggest that widespread adoption of biogas and biomethane as a substitute for natural gas will not significantly increase ambient concentrations of primary and secondary UFPs if advanced combustion technology is used and the sulfur and siloxane content is similar for biogas/biomethane and natural gas.