Levels Of Indoor Air Pollution Research Articles

Air Pollution in Urban Slums: Summary of research work in Bengaluru, India

Air Pollution in Urban Slums: Summary of research work in Bengaluru, IndiaMeghaThakur1, Prafulla Shriyan1, Giridhara R Babu11Indian Institute of Public Health Hyderabad- Bengaluru CampusAbstractBackground: Air pollution is a leading cause of morbidity, especially in low and middle-income countries (LMICs). In India, 2 million premature deaths are attributed to exposure to ambient and indoor air pollution annually. People residing in slums are particularly vulnerable to these health and environmental risks. We aimed to assess the association between low birth weight (LBW) and exposure to particulate matter (PM) and carbon monoxide (CO) during pregnancy. Also, we aimed to reduce the levels of indoor air pollution (IAP) and improve the respiratory health of women and children by introducing an improved cookstove.Methods: APPLE, a prospective cohort study of 516 pregnant women aged 18-45 years, was conducted in two big slums in Bangalore. Information was collected on socio-demographic and obstetric history. Exposures to PM2.5, PM10, and CO during pregnancy was measured using low-cost monitors. Another study, EXHALE, was conducted in slums among households using firewood for cooking. Information from women was collected on socio-demographics, cooking habits, respiratory and eye symptoms, and headache using a pre-structured questionnaire. Spirometry was performed to assess the lung function. Results: Our preliminary findings from APPLE did not find any association between LBW and exposure to PM2.5, PM10 and CO during pregnancy after adjusting for potential confounders. Data for EXHALE are still being entered, results will be shared later.Conclusion: Although cleaner fuels are available, some groups continue using solid fuels because of financial constraints, absence of infrastructure, and lack of awareness. Some two billion people in LMICs are expected to remain dependent on biomass fuel over the next 25 years. More research is needed in understanding the cooking dynamics in urban slums.

Impact of air pollution on reproductive health in Afghanistan

The presence of one or more contaminants (harmful substances) in the atmosphere in a specific quantity, for such duration, which is injurious or tends to be injurious to human health, welfare, animal, or plant life is called air pollution. Air pollutants are of commonly two types, which are produced through natural pollutants; they include dust (crustal material), sea salts, biological material, pollen, spores or plant-animal debris, volcanic eruptions (which release a very large quantity of gases and particles into the atmosphere), periodic forest fires, thunderbolts, wind erosion, and low concentration ozone. Other types of pollutants are produced in human-made (technical) environments, like mobile sources (cars, trucks, airplanes, marine engines, etc.) or point sources (factories, electric power plants, etc.). The high level of air pollution is a big problem all over the world and also in Afghanistan, and all residents of this country are severely exposed to this ever-worsening situation. Air pollution and other extraordinary environmental problems are factors that threaten the livelihood of millions of Afghans, as a study report shows that 60% of Kabul’s residents are exposed to increased levels of harmful toxins, such as, nitrous oxides and sulfur dioxide. According to the State of Global Air report, more than 26,000 afghan deaths could be attributed to pollution in 2007, but United Nations Assistance Mission in Afghanistan (UNAMA) documented nearly 3,500 civilian casualties from the war for the same time period, so air pollution is killing more Afghans than war because they burn anything possible to get energy and heat they need. Result of air sampling in major urban centers of Afghanistan shows high amounts of particulate matters (PM), benzo-a-pyrene, and polycyclic aromatic hydrocarbons (PAHs) originating from vehicle exhaust emission. The highest concentrations were founded in Kabul and Mazar-e-Sharif (13.6 ng/m3 ). The absence of industrial parks, nonconformity of environmental protection rules, especially by industries, urbanization, degradation of fertile lands, deforestation, seasonal winds, drought, internal migration, and low knowledge about pesticides and herbicides use, are factors that boost the severity of air pollution in Afghanistan. In Afghanistan, women are more exposed to high levels of indoor air pollution because they spend more time at home due to their cultural rules; also, women have responsibility for household activities, working in the kitchen to prepare food, they are exposed to poor sanitation and contaminated water supplies, they clean and sweep rooms and yards with inadequate protection equipment, which are significant sources of dust, so they are often exposed to high levels of smoke and dust for long periods.

Contributions of burning incense on indoor air pollution levels and on the health status of patients with chronic obstructive pulmonary disease.

BackgroundAmong Buddhist or Taoist Taiwanese residents, burning incense is a common source of indoor particulate matter (PM), including PM10 and PM2.5, and can adversely affect the health status of patients with chronic obstructive pulmonary diseases (COPD). However, few studies have focused on the effects of intermittent burning of incense on PM concentration levels and the health status of patients with COPD. This correlational cohort study aimed to investigate the association between burning incense exposure duration, indoor air pollution levels, and lung function in patients with COPD in Taiwan.MethodsWe assessed 18 outpatients at seven time points with moderate-to-severe COPD using the COPD Assessment Test (CAT), and lung function tests. PM level changes were assessed at seven intervals using generalized estimating equations.ResultsParticipants were primarily male (84%), with a mean age of 72.1 (standard deviation (SD) ± 9.3) years, and with a mean COPD duration of 3.7 (SD ± 3.1) years. Both PM10 and PM2.5 levels were the same as the background levels 1 h after incense burning. Burning incense may not influence lung function or symptom severity in patients with COPD in a short-time period. Air quality returned to baseline levels 1 h after burning incense.ConclusionPatients with COPD should avoid staying in rooms where incense is burnt, for up to 1 h. The small sample size and short study period may have influenced our results. Future longitudinal studies with larger sample sizes and long-term follow-ups are recommended.

INDOOR SHORT-TERM EXPOSURE TO AIRBORNE PARTICULATE MATTER FROM TRADITIONAL COOKSTOVES IN RURAL AREAS OF MALAWI. A CASE OF NSABWE AND BAULENI VILLAGES

This study was carried out to assess the short-term exposure to respirable particulate matter (PM2.5) from biomass combustion. A total of 24 households were sampled from two rural villages in Lilongwe, viz Nsabwe and Bauleni villages. Levels of particulate matter were measured using a portable gas detector. Indoor mean concentrations of PM2.5 ranged from 457 to 698 µg/m3, with no significant difference between the two villages, suggesting exposure to similar levels of airborne particulate matter. The observed levels are far above the recommended WHO limit for indoor air, posing a great health risk, more especially to the women and children who frequently visit the cooking areas. There is therefore need to widen appropriate intervention measures to reduce the current levels of indoor air pollution in the rural areas.

A long-term multi-parametric monitoring study: Indoor air quality (IAQ) and the sources of the pollutants, prevalence of sick building syndrome (SBS) symptoms, and respiratory health indicators

Poor indoor air quality (IAQ) can cause several respiratory diseases and symptoms. In this study, IAQ of 121 homes located in 3 different towns of Çanakkale, Turkey was monitored throughout a year. Target air pollutants were particulate matter, volatile organic compounds (VOCs), bioaerosols, and Carbon dioxide (CO2), as well as air temperature and humidity. Moreover, pulmonary functions of the occupants were measured on a monthly basis. Also, occurrence of sick building syndrome (SBS) symptoms and other health related data were gathered from the occupants by a detailed questionnaire. The SBS is a situation related to indoor air pollution in which the occupants of a building experience health or comfort related adverse effects that appear to be associated directly to the time spent in the “sick” building. Results of this study showed that the highest indoor air pollutant levels were observed in Çan town and the lowest levels were observed in Central town. Indoor levels of bioaerosols, particulate matter, benzene, Cladosporium spp., and Penicillium spp. as well as pulmonary functions of the occupants showed statistically significant differences between the locations of the homes (p < 0.001). Factor analysis implied that both indoor and outdoor originated sources contributed to IAQ. Even though the predominant SBS symptoms varied seasonally and spatially among the study sites, fatigue, cold-flu like symptoms, and difficulty in concentration occurred frequently. Correlations were found among the occurrence of SBS symptoms, measured IAQ parameters, and personal factors (p < 0.05). Performing more studies from the health and IAQ points of view improve public awareness.

Ambient and Indoor Air Pollution in Pregnancy and the risk of Low birth weight and Ensuing Effects in Infants (APPLE): A cohort study in Bangalore, South India

Background: Exposure to air pollution (IAP) from the combustion of solid fuels is a significant cause of morbidity and mortality in developing countries. Pregnant women exposed to higher pollutant levels are at higher risk of delivering a low-birth-weight (LBW) baby. There is a lack of standardized data regarding the levels and types of specific pollutants and how they impact LBW. We aim to prospectively assess the association between ambient and indoor air pollution levels in pregnancy and low birth weight and understand the subsequent risk of adiposity in these infants. Methods: We will conduct a prospective cohort study of 516 pregnant women recruited before 18 weeks of gestation in the urban slums of Bangalore, who have voluntarily consented to participate. We will estimate the level of air pollutants including particulate matter (&lt;10 μm, &lt;2.5 μm) and carbon monoxide (CO) parts per million (ppm) levels in both indoor and ambient environment. The follow-up of the delivered children will be done at delivery until the infant is one year old. The association between pollutants and LBW will be evaluated using logistic regression adjusting for potential confounders.Further, we will explore the mediation role of LBW in the hypothesized causal chain of air pollution and adiposity. Nested within a large cohort titled "Maternal Antecedents of Adiposity and Studying the Transgenerational role of Hyperglycemia and Insulin (MAASTHI)", we can estimate the absolute risk of having low birth weight caused by air pollution and other variables. Discussion: Understanding the association between exposures to ambient and indoor air pollution and low birth weight is essential in India. LBW babies have a higher risk of developing obesity and Non-Communicable Diseases (NCDs) during adulthood. The results from this study can inform the efforts for controlling the air pollution-related chronic diseases in India.

Is Exposure to Air Pollution a Risk Factor for COVID-19 Fatality Rate? Evidence from India As of May 15, 2020

Many studies have revealed the negative effects of air pollution on respiratory diseases, cardiovascular diseases, pregnancy outcomes, and neurocognitive diseases. In developing countries, notably in South Asia, both ambient air pollution (AAP) and household air pollution (HAP) cost millions of lives every year. However, the evidence linking air pollution exposure to COVID-19 deaths is scarce in the developing country context as most existing studies are focused on moderately polluted countries such as the US, Italy, Spain, France, and Germany. Our study fills this gap by investigating the link between air pollution exposure and the COVID-19 fatality rate in India as of May 15, 2015. We use PM2.5 levels and the share of biomass for cooking indoors as proxies to measure exposure to AAP and HAP, respectively. The results using inference with arbitrary clustering in space suggest that the COVID-19 fatality rate is positively correlated to HAP, but not to AAP. This result could be specific to India. However, it may apply to other developing countries, where a high level of indoor air pollution is a critical development and health issue. Further investigation is needed to establish causality and to use the latest data available as COVID-19 cases and deaths in India continue to rise.

Solar Home Systems for Clean Cooking: A Cost–Health Benefit Analysis of Lower-Middle-Income Countries in Southeast Asia

Limited access to clean energy has long been an obstacle to livelihood improvement of populations mired in energy poverty. Cooking with traditional biomass contributes to high levels of indoor air pollution, thus imposing significant threats to public health. Due to the accessibility and affordability of clean fuels for rural residents, this study proposes that renewable solar energy be employed to supply power for induction cooking stoves (ICS) through solar home systems (SHS), and estimates both the costs and health benefits of upgrading to ICS and SHS in lower-middle-income countries (LMCs) in Southeast Asia. Disability-Adjusted Life Years and the value of a statistical life year were employed to estimate the health benefits of ICS-SHS. The results suggest that the health benefits brought by ICS-SHS alone can surpass the estimated minimum cost for an ICS-SHS in the six LMCs in Southeast Asia. This study provides a potential reference for getting other energy poverty regions involved with affordable, reliable, sustainable, and modern energy, as well as simultaneously tackling indoor air pollution caused by cooking.

The global, regional, and national burden of oesophageal cancer and its attributable risk factors in 195 countries and territories, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017

SummaryBackgroundOesophageal cancer is a common and often fatal cancer that has two main histological subtypes: oesophageal squamous cell carcinoma and oesophageal adenocarcinoma. Updated statistics on the incidence and mortality of oesophageal cancer, and on the disability-adjusted life-years (DALYs) caused by the disease, can assist policy makers in allocating resources for prevention, treatment, and care of oesophageal cancer. We report the latest estimates of these statistics for 195 countries and territories between 1990 and 2017, by age, sex, and Socio-demographic Index (SDI), using data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD).MethodsWe used data from vital registration systems, vital registration-samples, verbal autopsy records, and cancer registries, combined with relevant modelling, to estimate the mortality, incidence, and burden of oesophageal cancer from 1990 to 2017. Mortality-to-incidence ratios (MIRs) were estimated and fed into a Cause of Death Ensemble model (CODEm) including risk factors. MIRs were used for mortality and non-fatal modelling. Estimates of DALYs attributable to the main risk factors of oesophageal cancer available in GBD were also calculated. The proportion of oesophageal squamous cell carcinoma to all oesophageal cancers was extracted by use of publicly available data, and its variation was examined against SDI, the Healthcare Access and Quality (HAQ) Index, and available risk factors in GBD that are specific for oesophageal squamous cell carcinoma (eg, unimproved water source and indoor air pollution) and for oesophageal adenocarcinoma (gastro-oesophageal reflux disease).FindingsThere were 473 000 (95% uncertainty interval [95% UI] 459 000–485 000) new cases of oesophageal cancer and 436 000 (425 000–448 000) deaths due to oesophageal cancer in 2017. Age-standardised incidence was 5·9 (5·7–6·1) per 100 000 population and age-standardised mortality was 5·5 (5·3–5·6) per 100 000. Oesophageal cancer caused 9·78 million (9·53–10·03) DALYs, with an age-standardised rate of 120 (117–123) per 100 000 population. Between 1990 and 2017, age-standardised incidence decreased by 22·0% (18·6–25·2), mortality decreased by 29·0% (25·8–32·0), and DALYs decreased by 33·4% (30·4–36·1) globally. However, as a result of population growth and ageing, the total number of new cases increased by 52·3% (45·9–58·9), from 310 000 (300 000–322 000) to 473 000 (459 000–485 000); the number of deaths increased by 40·0% (34·1–46·3), from 311 000 (301 000–323 000) to 436 000 (425 000–448 000); and total DALYs increased by 27·4% (22·1–33·1), from 7·68 million (7·42–7·97) to 9·78 million (9·53–10·03). At the national level, China had the highest number of incident cases (235 000 [223 000–246 000]), deaths (213 000 [203 000–223 000]), and DALYs (4·46 million [4·25–4·69]) in 2017. The highest national-level age-standardised incidence rates in 2017 were observed in Malawi (23·0 [19·4–26·5] per 100 000 population) and Mongolia (18·5 [16·4–20·8] per 100 000). In 2017, age-standardised incidence was 2·7 times higher, mortality 2·9 times higher, and DALYs 3·0 times higher in males than in females. In 2017, a substantial proportion of oesophageal cancer DALYs were attributable to known risk factors: tobacco smoking (39·0% [35·5–42·2]), alcohol consumption (33·8% [27·3–39·9]), high BMI (19·5% [6·3–36·0]), a diet low in fruits (19·1% [4·2–34·6]), and use of chewing tobacco (7·5% [5·2–9·6]). Countries with a low SDI and HAQ Index and high levels of indoor air pollution had a higher proportion of oesophageal squamous cell carcinoma to all oesophageal cancer cases than did countries with a high SDI and HAQ Index and with low levels of indoor air pollution.InterpretationDespite reductions in age-standardised incidence and mortality rates, oesophageal cancer remains a major cause of cancer mortality and burden across the world. Oesophageal cancer is a highly fatal disease, requiring increased primary prevention efforts and, possibly, screening in some high-risk areas. Substantial variation exists in age-standardised incidence rates across regions and countries, for reasons that are unclear.FundingBill & Melinda Gates Foundation.

Novel Approaches to Air Pollution Exposure and Clinical Outcomes Assessment in Environmental Health Studies

An accurate assessment of pollutants’ exposure and precise evaluation of the clinical outcomes pose two major challenges to the contemporary environmental health research. The common methods for exposure assessment are based on residential addresses and are prone to many biases. Pollution levels are defined based on monitoring stations that are sparsely distributed and frequently distanced far from residential addresses. In addition, the degree of an association between outdoor and indoor air pollution levels is not fully elucidated, making the exposure assessment all the more inaccurate. Clinical outcomes’ assessment, on the other hand, mostly relies on the access to medical records from hospital admissions and outpatients’ visits in clinics. This method differentiates by health care seeking behavior and is therefore, problematic in evaluation of an onset, duration, and severity of an outcome. In the current paper, we review a number of novel solutions aimed to mitigate the aforementioned biases. First, a hybrid satellite-based modeling approach provides daily continuous spatiotemporal estimations with improved spatial resolution of 1 × 1 km2 and 200 × 200 m2 grid, and thus allows a more accurate exposure assessment. Utilizing low-cost air pollution sensors allowing a direct measurement of indoor air pollution levels can further validate these models. Furthermore, the real temporal-spatial activity can be assessed by GPS tracking devices within the individuals’ smartphones. A widespread use of smart devices can help with obtaining objective measurements of some of the clinical outcomes such as vital signs and glucose levels. Finally, human biomonitoring can be efficiently done at a population level, providing accurate estimates of in-vivo absorbed pollutants and allowing for the evaluation of body responses, by biomarkers examination. We suggest that the adoption of these novel methods will change the research paradigm heavily relying on ecological methodology and support development of the new clinical practices preventing adverse environmental effects on human health.

Sensing Data Fusion for Enhanced Indoor Air Quality Monitoring

Multisensor fusion of air pollutant data in smart buildings remains an important input to address the well-being and comfort perceived by their inhabitants. An integrated sensing system is part of a smart building where real-time indoor air quality data are monitored round the clock using sensors and operating in the Internet-of-Things (IoT) environment. In this work, we propose an air quality management system merging indoor air quality index (IAQI) and humidex into an enhanced indoor air quality index (EIAQI) by using sensor data on a real-time basis. Here, indoor air pollutant levels are measured by a network of waspmote sensors while IAQI and humidex data are fused together using an extended fractional-order Kalman filter (EFKF). According to the obtained EIAQI, overall air quality alerts are provided in a timely fashion for accurate prediction with enhanced performance against measurement noise and nonlinearity. The estimation scheme is implemented by using the fractional-order modeling and control (FOMCON) toolbox. A case study is analysed to prove the effectiveness and validity of the proposed approach.

Indoor air quality prediction systems for smart environments: A systematic review

Air quality is a critical matter of concern in terms of the impact on public health and well-being. Although the consequences of poor air quality are more severe in developing countries, they also have a critical impact in developed countries. Healthcare costs due to air pollution reach $150 billion in the USA, whereas particulate matter causes 412,000 premature deaths in Europe, every year. According to the Environmental Protection Agency (EPA), indoor air pollutant levels can be up to 100 times higher in comparison to outdoor air quality. Indoor air quality (IAQ) is in the top five environmental risks to global health and well-being. The research community explored the scope of artificial intelligence (AI) in the past years to deal with this problem. The IAQ prediction systems contribute to smart environments where advanced sensing technologies can create healthy living conditions for building occupants. This paper reviews the applications and potential of AI for the prediction of IAQ to enhance building environment and public health. The results show that most of the studies analyzed incorporate neural networks-based models and the preferred evaluation metrics are RMSE, R 2 score and error rate. Furthermore, 66.6% of the studies include CO2 sensors for IAQ assessment. Temperature and humidity parameters are also included in 90.47% and 85.71% of the proposed methods, respectively. This study also presents some limitations of the current research activities associated with the evaluation of the impact of different pollutants based on different geographical conditions and living environments. Moreover, the use of reliable and calibrated sensor networks for real-time data collection is also a significant challenge.

Houseplant, indoor air pollution, and cardiovascular effects among elderly subjects in Taipei, Taiwan

Previous studies have documented the linkage between houseplant usage and indoor air quality (IAQ) improvement. However, the effect of houseplant on the association between indoor air quality and cardiovascular health is still unknown. We recruited 100 elderly subjects from 100 houses with (50) or without houseplants (50) in Taipei and conducted six 24-hour house visits for each elderly subject between 2015 and 2016. The particulate matter less than or equal to 2.5 μm in diameter (PM2.5), total volatile compounds (TVOCs), heart rate (HR) and blood pressure (BP) were continuously measured in each house visit. The association between indoor air pollution, BP and HR was investigated by mixed-effects. We found that the elderly subjects in houses without houseplants were exposed to higher indoor PM2.5 and TVOCs levels compared to the elderly subjects' exposures in houses with houseplants. Also, the elderly subjects' HR, systolic BP (SBP) and diastolic BP (DBP) were higher in houses without houseplants than those in houses with houseplants. Moreover, high indoor air pollution levels were associated with elevated BP and HR, especially among subjects in houses without houseplants. Accordingly, we concluded that indoor air pollution was associated with cardiovascular effects. Houseplant could improve IAQ and cardiovascular health among elderly subjects in Taipei, Taiwan.

Evaluation of the Effect of an Exhaust Reduction System in Fire Stations

Firefighters are known to be exposed to a variety of hazardous materials and combustion products during operational and training activities, as well as in fire stations. However, exposure to diesel exhaust emissions, classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC), is also present in the fire station environment. In this study, concentrations of elemental carbon (EC), which is a surrogate of diesel exhaust and indoor air pollutants, has been measured to compare the effect of an exhaust reduction system (ERS) that was installed in the engine bays of two fire stations to mitigate indoor air pollution levels in the garage, duty offices, and dormitory/shower areas. The levels of most pollutants were reduced after the installation of the ERS. Pollutants may disperse inside of fire stations. Therefore, the ERS is a valuable strategy to mitigate pollutant exposure among firefighters and outdoor air pollution using the filtration ability of an ERS. The results of this study suggest that all truck bays should install an ERS to reduce pollutant exposure and that installation is especially necessary for EURO 3 fire vehicles.

Ambient and Indoor Air Pollution in Pregnancy and the risk of Low birth weight and Ensuing Effects in Infants (APPLE): A cohort study in Bangalore, South India

Background: Exposure to air pollution (IAP) from the combustion of solid fuels is a significant cause of morbidity and mortality in developing countries. Pregnant women exposed to higher pollutant levels are at higher risk of delivering a low-birth-weight (LBW) baby. There is a lack of standardized data regarding the levels and types of specific pollutants and how they impact LBW. We aim to prospectively assess the association between ambient and indoor air pollution levels in pregnancy and low birth weight and understand the subsequent risk of adiposity in these infants. Methods: We will conduct a prospective cohort study of 516 pregnant women recruited before 18 weeks of gestation in the urban slums of Bangalore, who have voluntarily consented to participate. We will estimate the level of air pollutants including coarse particulate matter 10 ug/m3 (PM10 ), fine particulate matter 2.5 ug/m3(PM2.5) and carbon monoxide (CO) parts per million (ppm) levels in both indoor and ambient environment. The follow-up of the delivered children will be done at delivery until the infant is two years old. The association between pollutants and LBW will be evaluated using logistic regression adjusting for potential confounders.Further, we will explore the mediation role of LBW in the hypothesized causal chain of air pollution and adiposity. Nested within a larger Maternal Antecedents of Adiposity and Studying the Transgenerational role of Hyperglycemia and Insulin (MAASTHI) cohort, we can estimate the absolute risk of having low birth weight caused by air pollution and other variables. Discussion: Understanding the association between exposures to ambient and indoor air pollution and low birth weight is essential in India. LBW babies have a higher risk of developing obesity and Non-Communicable Diseases (NCDs) during adulthood. The results from this study can inform the efforts for controlling the air pollution-related chronic diseases in India.

A new way of analyzing how the association between lung cancer and indoor air pollution is altered by tobacco use

TPS 901: Indoor air pollution, Exhibition Hall, Ground floor, August 28, 2019, 3:00 PM - 4:30 PM Background: Xuanwei is a city with significantly high lung cancer mortality. Indoor air pollution was a historical risk factor, while tobacco should not be neglected as well there. We aimed to investigate current impacts of indoor air pollution, smoking and SHS exposure on lung cancer risk in Xuanwei, by a conventional process and a novel one, respectively, so that we could also study the methodology for the evaluation of two competitive risk factors. Methods: We followed a case control study design. In conventional analysis process, we built unconditional logistic regression models with both indoor air pollution and smoking or SHS exposure, and estimated their odd ratios (OR) and 95% confidence intervals (CI) at the same time. In novel analysis process, we firstly estimated the OR (95%CI) of indoor air pollution or smoking or SHS exposure separately, and then calculated the alteration smoking or SHS exposure caused on the effect size of indoor air pollution. Results: The ORs estimated for medium or high indoor air pollution level ranged from 2.24 to 4.69 or 6.04 to 9.54, respectively. These values kept the same no matter whether smoking or SHS exposure were included in the models at the same time. Only by using the novel process, we could find out that the effect size of indoor air pollution would decrease 12%-19%, when facing the competition from tobacco. Conclusions: Nowadays, there is still a strong association between lung cancer risk and air pollution in Xuanwei, at the same time the effect of smoking or SHS is gradually highlighted. The issue of indoor air pollution needs to be further solved, while smoking cessation promotion and SHS exposure prevention is also in need. The novel way of analysis should be worth spreading, when there are two kinds of risk factors may be confused with each other.

The effects of temperature and humidity on the VOC emission rate from dry building materials

With the development of the economy and society, a wide variety of new building decoration and materials are widely used indoors. The concentration of pollutants such as formaldehyde, volatile organic compounds, benzene and ammonia in indoor air witnessed increase, causing increasingly serious indoor air pollution problems. Indoor building decoration materials are one of the main sources of indoor VOCs. In this paper, the emission law of VOCs in dry building materials with environmental conditions is studied. The environmental test cabin is used to test the formaldehyde and TVOC concentration released. The single factor variable method is used to study how different environmental conditions (temperature and relative humidity) affect the rate of formaldehyde and TVOC released from dry building materials. According to the results, increase of ambient temperature and relative humidity will promote the release of TVOC, which will affect its peak concentration and stable concentration, and the effect on formaldehyde release is more significant. This study clarified the release law of VOCs in artificial boards under different environmental conditions, which is of great significance for reducing indoor air pollutant levels and improving indoor air quality.

Status, standards, technologies and existing problems of residential ventilation in China

Indoor air pollution level in dwellings varies in different areas. Specifically, the formaldehyde and total volatile organic compound pollution are serious in new residential buildings according to the investigation of indoor air pollution status of residential buildings in China. Appropriate ventilation, as an important means to reduce the concentration of indoor pollutants, is mainly affected by ventilation mode, ventilation performance, ventilation strategies, etc. This paper analyses the status, standards, technologies and products related to residential ventilation and concludes the existing drawbacks in residential ventilation applications in China. Understanding of residential ventilation, and its standards, design methods, technologies, products, also the economy and usability should be given a major consideration to research.

Quantifying indoor air quality determinants in urban and rural nursery and primary schools

Poor indoor air quality can adversely affect children's health, comfort and school performance, but existing literature on quantifying indoor air pollutants (IAP) determinants' in nursery and primary schools is limited. Following previous studies, this study mainly aimed to quantify determinants of selected IAP, in nursery and primary schools from both urban and rural sites, accounting for seasonal variations. In 101 indoor microenvironments (classrooms, bedrooms and canteens) from 25 nursery and primary schools, CO2, CO, HCOH, NO2, O3, total volatile organic compounds, PM1, PM2.5, PM10, total suspended particles (TSP), and meteorological/comfort parameters were continuously sampled (occupancy and background levels), from at least 24 h to 9 consecutive days (not simultaneously) in each studied room; in some cases weekend was also considered.Children faced thermal discomfort and inadequate humidity, respectively in 60.1% and 44.1% of the studied classrooms. They were also exposed to high levels of IAP, namely PM2.5 and CO2 respectively in 69.0% and 41.3% of the studied classrooms, mostly in urban sites, depending on season and on occupancy and activity patterns (different amongst age groups). As PM2.5 and CO2 were the major concerning IAP, multivariate linear regression models were built to quantify (explained variability and relative importance) their main determinants, in both occupancy and non-occupancy (background) periods. Models for occupancy periods showed higher explained variability (R2 = 0.64, 0.57 and 0.47, respectively, for CO2, PM2.5 and PM10) than for non-occupancy. Besides background concentrations (43.5% of relative importance), relative humidity (21.1%), flooring material (17.0%), heating (6.7%) and age group of the occupants (5.3%), adjusted for season of sampling (6.4%) were predictors in CO2 occupancy model. In the cases of PM2.5 and PM10 occupancy concentrations, besides background concentrations (71.2% and 67.2% of relative importance, respectively for PM2.5 and PM10), type of school management (8.8% and 15.2%) and flooring material (13.9% and 13.9%), adjusted for season of sampling (6.1% and 3.8%), were the main predictors.These findings support the need of mitigation measures to reduce IAP levels, and prevention actions to avoid children's exposure. Reducing the time spent indoors in the same microenvironment by doing more and/or longer breaks, improving ventilation and cleaning actions, and avoiding or making a better maintenance hardwood flooring materials, chalkboard use and VOC emitting materials, are practices that should be implemented and their impacts quantified.

Individual exposure level following indoor and outdoor air pollution exposure in Dakar (Senegal)

The consequences of indoor and outdoor air pollution on human health are of great concern nowadays. In this study, we firstly evaluated indoor and outdoor air pollution levels (CO, CO2, NO, NO2, PM10) at an urban site in Dakar city center and at a rural site. Then, the individual exposure levels to selected pollutants and the variations in the levels of biomarkers of exposure were investigated in different groups of persons (bus drivers, traders working along the main roads and housemaids). Benzene exposure levels were higher for housemaids than for bus drivers and traders. High indoor exposure to benzene is probably due to cooking habits (cooking with charcoal), local practices (burning of incense), the use of cleaning products or solvent products which are important emitters of this compound. These results are confirmed by the values of S-PMA, which were higher in housemaids group compared to the others. Urinary 1-HOP levels were significantly higher for urban site housemaids compared to semirural district ones.Moreover, urinary levels of DNA oxidative stress damage (8-OHdG) and inflammatory (interleukin-6 and -8) biomarkers were higher in urban subjects in comparison to rural ones.The air quality measurement campaign showed that the bus interior was more polluted with PM10, CO, CO2 and NO than the market and urban or rural households. However, the interior of households showed higher concentration of VOCs than outdoor sites confirming previous observations of higher indoor individual exposure level to specific classes of pollutants.