Indoor Air Pollution as a Risk Factor for Lung Cancer - Assignment Example

Executive Summary In the UK, most individuals spend over 80% of their time completing activities in indoor environments, such as schools, offices, private homes, shopping centres, hospitals, day care and so on. Therefore, an assessment of the health risks associated with contaminated air is essential to assist stakeholders in taking the appropriate measures to promote strategies for reducing the emissions of appliances, controlling indoor emissions and individual exposure to harmful emissions. This study examines the relationship between gas stoves and household heating appliances and their contribution to the emission of nitrogen dioxide, and thus the health risk they pose to the human respiratory system. However, the approaches used to measure nitrogen dioxide emissions by various appliances, as well as the health implications of such emissions for individuals, do not provide clear information to stakeholders on the appropriate measures for reducing the level of, and exposure to, such emissions. Table of Content Executive Summary 1 1- Introduction 4 2- Background 4 3- Safety, Health and Environmental Hazards to Different Key Actors 5 3.1 Women’s risk of exposure to indoor nitrogen dioxide 6 3.2 Risk of Exposure to indoor emissions to asthmatic Persons 6 3.3 Risk of indoor nitrogen dioxide exposure to pre-school children 7 4- Evaluation of the Appropriateness of Key Tools to Assess Risk, and Relevant Sources 7 4.1 Techniques for investigating health effects 7 4.2 Variation in human susceptibility to pollutants 9 4.3 Lack of consistency in research findings 10 5- Synthesis of Evidence for Particular Stakeholders 12 5.1 Department for Communities and Local Government (CLG) 12 5.2 Department of Environment, Food and Rural Affairs (Defra) 15 5.3 Department of Health and the Health Protection Agency (HPA) 16 6- Summary 17 7- Bibliography 18 Crown, (2012). Improving the energy efficiency of buildings and using planning to protect the environment. Retrieved from 18 Crown, (2012). National Planning Policy Framework. Retrieved from 18 1- Introduction Due to the long periods of time individual spend indoors, indoor air quality (IAQ) can be seen to affect health. Household heaters and gas stoves make a significant contribution to the emission of indoor gases, which determine the indoor air quality (Noonan & Ward, 2007). Other factors, such as the nature of buildings, the duration of exposure and individual characteristics affect the influence of indoor emissions on human respiratory diseases. Although nitrogen dioxide is not the only emission produced by heaters, the concentration levels of this gas have significant effects on respiratory functions (Willers et al., 2005). This study will also examine the impact of various measurement strategies used to determine the effects of pollution on human health and how different heating appliances and gas stoves affect the level of emissions. Finally, the study will examine some appropriate stakeholder interventions, in order to address the issue of indoor emission of nitrogen dioxide and the management of health risks associated with human exposure to indoor emissions. 2- Background Indoor nitrogen dioxide levels are influenced by the outdoor nitrogen dioxide concentration. Studies show that in a well-ventilated building the ratio of indoor to outdoor nitrogen dioxide is 0.88 to 1 (Tarlo et al., 2011). Buildings located in areas with a high outdoors concentration of nitrogen dioxide, for example areas close to garages, roads and schools, have a high concentration of nitrogen dioxide (Gilbert et al., n.d.). However, the presence of indoor pollutants also has significant influence on the rate of indoor carbon dioxide concentration (Tarlo et al., 2011). Further studies indicate that during winter the level of indoor nitrogen dioxide concentration is comparatively higher than concentrations during summer, as a result of more frequent use of heating appliances to warm rooms, low ventilation and increased cooking activities (Willers et al., 2005). The use of candles and mosquito coils also contribute immensely to the indoor concentration of nitrogen dioxide. 3- Safety, Health and Environmental Hazards to Different Key Actors The combustion of nitrogen and oxygen at high temperatures in ambient air results in the formation of nitrogen oxides (Gent et al., 2004). As temperature increases, more nitric oxides are formed. Home heating appliances and cooking stoves produces gases, including carbon monoxide, nitrogen dioxide and particulate matters during combustion, which may cause health complications to exposed individuals. Heating sources include gas stoves, wood stoves, kerosene heaters, hot water heaters, gas dryers, fireplaces and flues, among others (WHO, 2010). 3.1 Women’s risk of exposure to indoor nitrogen dioxide According to WHO (2010), women are more exposed to indoor kitchen emissions than men because they spend more time cooking for their families or hired as professional cooks in hotels and hospitals. According to the Institute for Environment and Health (1996), the rate of nitrogen dioxide is higher in kitchen areas than in other parts of the house caused by regular combustion of fuels. According to WHO (2010), a study conducted in Vlaardingen involving 229 women established a positive relationship between lung function and exposure to nitrogen dioxide. It therefore follows that indoor emissions represent a significant threat to women’s health, as they spend most of their time indoors. 3.2 Risk of Exposure to indoor emissions to asthmatic Persons A study involving 117 families, including both asthmatic and non-asthmatic individuals, used diaries to monitor the rate of asthma symptoms (Tarlo et al., 2011). The participants provided information about the heating systems used in their homes, and monitoring was carried out via telephone. The findings demonstrate that the occurrence of asthmatic symptoms is greater in homes using gas cookers than in those that use other types of cookers (Institute for Environment and Health, 1996). In addition, the rate of rhinitis is higher in homes using gas cookers where there are no asthmatic individuals. Therefore, exposure to nitrogen dioxide has greater effects on asthmatics than people with good health. 3.3 Risk of indoor nitrogen dioxide exposure to pre-school children In this section, ‘pre-school’ children are taken to mean children aged six years and below (Wong, 2004). Although children are exposed to both indoor and outdoor pollution, they spend more time indoors than outdoors (Tarlo et al., 2011). Therefore, indoor pollution has a greater effect on pre-school children than outdoor exposure does. A study investigating the effects of cooking gas on per-school demonstrates that exposure to cooking gas increases the prevalence of respiratory illnesses; children from families using cooking gases exhibit higher rates of respiratory disease attacks than those from families using other cooking methods (Wong, 2004). In addition, those children from families cooking three meals a day are exposed to more risk than those from families who prepare less than three meals a day (Crown, 2012). Therefore, pre-school have a higher risk of exposure to indoor emissions of nitrogen dioxide through cooking gases, as they spend more time indoors than they spend outdoors (Wong, 2004). 4- Evaluation of the Appropriateness of Key Tools to Assess Risk, and Relevant Sources 4.1 Techniques for investigating health effects There are various possible approaches to evaluating the effects of indoor pollutants. Different heating appliances and gas stoves vary in terms of efficiency and duration of combustion. Furthermore, the indoor emission of nitrogen dioxide is also influenced by outdoor emissions, which in turn vary according to their proximity to schools, garages and roads (Hasselaar, 2006). This implies that indoor emissions cannot determined without considering the influence of outdoor emissions. In light of this revelation it is hard to arrive at a conclusion regarding which appliances have the greatest effect on indoor air quality without also considering the surroundings and nature of specific devices. There are several challenges relating to the methods used to evaluate human exposure to indoor emissions; moreover, these problems cannot be quantified, due to varying micro-environmental characteristics across households, influenced by the availability and usage of pollutants and the degree of ventilation in individual houses (McGwin et al., 2010). Furthermore, some approaches used for measuring ambient air pollution are inappropriate for indoor investigations, in light of the bulkiness and cost of the apparatus as well as the quantity of air displaced (Institute for Environment and Health, 1996). In addition, most indoor devices used for measuring emissions measure the average concentrations over a relatively long period. Therefore, such methods may not be able to determine the concentration of pollutants with acute effects such as nitrogen dioxide if the exposure took short duration (Willers et al., 2005). Most of the approaches used to measure human exposure to emissions rely on the source of the pollutant used, usage time patterns and strength of pollution. Occasionally, biological monitoring is used to determine the level of exposure, by analysing the exhaled air, urine and blood (WHO, 2009). The relationship between the biological media and environmental level of pollution is examined and the outcome of findings integrated into an examination of human exposure to pollutants (Noonan & Ward, 2007). However, unlike animals that are caged during experiment human beings interact with both indoor and outdoor emissions makes it hard to determine the actual effects of household heaters on human health. 4.2 Variation in human susceptibility to pollutants Owing to the diversity of the human race, persons exposed equally to pollution exhibit varying effects. This implies that evaluating levels of vulnerability does not yield accurate information regarding the rate of pollution caused by various gas stoves and household heaters, risk of exposure to nitrogen oxide or the effects of exposure on respiratory conditions (Caillaud et al., 2010). As humans have varying degrees of immunity and thus respond differently to similar environmental conditions, any conclusion drawn from an investigation of a group of participants over a period of time may be erroneous. Furthermore, some experiments undertaken to determine the effects of human exposure to nitrogen dioxide and other emissions from gas stoves and household heaters use animals as specimens (Wong, 2004). Studies show that indoor pollution has various biological impacts on experimental animals, including changes in metabolism, functions, structures and inflammation, to name a few (Noonan & Ward, 2007). These studies also show that the nature of the effect depends on the sex, age, duration of exposure, species, etc. (Caillaud et al., 2010). Researchers generalise results obtained from the investigation of animals in order to draw conclusions regarding the impact similar exposure might have on human beings (WHO, 2010). However, drawing a conclusion regarding humans from such results is problematic, as there are significant variations in the concentration of nitrogen dioxide in the alveoli and airways of different animal species (Noonan & Ward, 2007). Different species of animals used in experiments, including dogs and rats, have exhibited varying characteristics; thus, there is no assurance that the same experimental conditions would yield similar results if applied to a human being. 4.3 Lack of consistency in research findings Although it is not possible to eliminate the emission of nitrogen dioxide completely, it is essential for stakeholders to protect humans against excessive exposure, in order to reduce the negative effects it has on respiratory health (Willers et al., 2005). However, lack of consistency among various studies means that the appropriate intervention measures to ensure healthy living are not clear. For example, different techniques used by researchers suggest ambiguity in regards to the relationship between exposure and response, between short-term and long-term exposure, and in establishing the essential margin of safety (Kovesi & Dales, 2009). Some studies indicate a high degree of correlation between asthma and exposure to nitrogen dioxide (Willers et al., 2005). On the other hand, several studies involving large populations have failed to provide consistent evidence pertaining to the effects of indoor exposure on pulmonary functions (WHO, 2010). The few number of individuals sampled during an experiment can provide conclusive evidence regarding varying human sensitivity to nitrogen dioxide exposure (Institute for Environment and Health, 1996). However, individuals may be more or less sensitive to various concentrations of nitrogen dioxide exposures than the experimental sample (Noonan & Ward, 2007). Furthermore, due to the complexity of research involving different specimens over different exposure periods with varying durations of exposure are inaccurate for determining the changing trend of effects of human exposure to nitrogen dioxide (McGwin et al., 2010). Further inconsistencies result from investigating different participant groups. For example, some researchers study children with respiratory illnesses, such as asthma, others use adults, and some use infants, based on their susceptibility to respiratory diseases (Anderson, 1996). This use of different groups of participants for the research activity results in inconsistent findings, which presents a challenge in decision-making. 5- Synthesis of Evidence for Particular Stakeholders Indoor pollution poses a major health risk in the UK, as the majority of citizens spend most of their time indoors (WHO, 2010). Nitrogen dioxide produced through combustion continues to be the primary pollutant of indoor environments (Fernandez et al., 2013). However, outdoor pollution has a significant effect on the quality of the indoor environment, thus making it hard for policy makers to determine the necessary intervention to minimise the harmful effects of indoor pollution (Crown, 2012). Therefore, to ensure effective policy intervention in relation to indoor pollution, stakeholders should focus on the causes of indoor pollution rather than reflecting on outdoor sources and concentrations of pollution (Anderson, 1996). The conclusions of various research studies have not isolated nitrogen dioxide as the core pollutant of the indoor environment; therefore, policy interventions should focus on improving the quality of heating and cooking devices, and housing conditions in general, in order to control the concentration of nitrogen dioxide emissions in houses (Sear, 2004). 5.1 Department for Communities and Local Government (CLG) The nature of a building influences its degree of ventilation and energy efficiency, which in turn determines the concentration of indoor nitrogen dioxide. The CLG sets UK building regulations regarding energy efficiency and ventilation in the Approved Documents of Building Regulations. These documents provide guidelines for air tightness, ventilation and indoor air quality standards; however, the guidelines apply only to new buildings, without any mention of old buildings. The CLG should ensure that residential buildings have adequate ventilation by recommending that homeowners install chimneys in their kitchen areas in order to reduce indoor pollution and thus concentrations of nitrogen dioxide and other emissions (Gillespie-Bennett et al., 2011). In addition, they should encourage the use of effective extractor fans indoors to improve the rate of air circulation. Large kitchens and the use of other ventilation sources, such as windows and ceiling fans, also influence indoor concentrations of emissions (Jarvis et al., 2005). As a result of climate change, there is increasing demand for airtight in UK and other parts of the globe (WHO, 2010). Highly airtight buildings are less ventilated and may accumulate more nitrogen dioxide; however, the reduction in ventilation may result in increased concentration of air pollutants. Therefore, the CLG should support new building designs that minimise levels of indoor pollution in order to reduce the degree of human exposure. The Department for Communities and Local Government is responsible for issuing directives to homeowners concerning the nature of the houses that should be built, in order to improve indoor environments (Postnote, 2010). All houses should have adequate ventilation and insulation, so as to minimise the use of heating devices and thus reduce the amount of nitrogen dioxide emitted indoors. The CLG should also focus on formulating strategies to regulate the level of nitrogen dioxide released from heating appliances in households and take appropriate measures to control the concentration of indoor emissions once they have been emitted (Perez-Padilla et al., 2010). The CLG should further ensure that all homeowners failing to comply with policy guidelines face legal action and be compelled to adhere to requirements. To this end, a means of inspecting houses should be established in order to identify those individuals failing to comply with policy requirements (Institute for the Environment and Health, 1996). These policy interventions include providing education on strategies to reduce indoor emissions of nitrogen dioxide, setting up building codes to regulate certain characteristics of the building, communication regarding the general risks of emissions and ensuring that heating appliances are adequately labelled to indicate the rate of emissions they release into the environment (Sabin et al., 2006). Therefore, the CLG should request that household owners install audible nitrogen dioxide alarms in order to help control the level of indoor emissions 5.2 Department of Environment, Food and Rural Affairs (Defra) The Department of Environment, Food and Rural Affairs is responsible for controlling the amount of pollution generated by various sources (Postnote, 2010). The nature of heating appliances and stoves used in households also has a significant influence on their level of indoor emissions (Willers et al., 2005). For example, the efficiency and the fuel source of heating appliances determine the quality and amount of emissions released, and thus the level of human exposure to related pollution; more efficient heating devices emit less nitrogen dioxide and so their adverse effect on dwellers is less. Furthermore, research shows that gas stoves are the main contributors to indoor emissions in the UK (Balamugesh & Behera, 2005). Therefore, it is the role of Defra to recommend which heating appliances are preferable to be used for cooking and heating, in order to minimise household emissions (Noonan & Ward, 2007). They should also create awareness regarding the effects of various cooking and heating appliances, and issue policy recommendations as to the minimum quality of different appliances (Institute for Environment and Health, 1996). Furthermore, they should also encourage the use of fuel-free appliances, which will reduce the rate of indoor emissions. 5.3 Department of Health and the Health Protection Agency (HPA) Various studies carried to establish the effects of nitrogen dioxide on respiratory conditions use different approaches but all subject to some errors. For example, the uses of animal samples in the studies are subject to errors due to incompatibility of animal structures and those of human beings (WHO, 2010). In addition, existing studies do not differentiate the level of exposure to indoor pollution from outdoor pollution. Therefore, the methods used are erroneous and do not suggest a standard relationship between the causes and effects of indoor pollution and respiratory disorders (McGwin et al., 2010). Consequently, the HPA must conduct research in order to properly establish the health risks associated with various emissions, and identify means to control the effects of such emissions on human health. In order to establish the actual effects of household heating appliances on indoor nitrogen dioxide emissions and associated respiratory risks, researchers should seek to establish the relationship between specific emissions and associated health risks (Billionnet, et al., 2011). The HPA should also raise public awareness of the effects of indoor emissions of nitrogen dioxide to enable people to minimise their exposure to these emissions. 6- Summary Heating appliances affect the level of indoor emissions of nitrogen dioxide. The nature of appliances used, their efficiency, the duration of human exposure to emissions and the characteristics of buildings all determine the effects of indoor emissions on human respiratory conditions. The conclusions of existing research and data do not reflect the actual effects of various appliances on indoor nitrogen dioxide emissions and the associated respiratory risks in human beings. Policy guidelines are necessary to inform users of different heating devices of the effects of different emissions, various building characteristics, the nature of the risks they are exposed to and how to manage individual exposure to these emissions. In addition, there remains a need to establish the relationship between particular emissions and related health risks in order to mitigate their effects on human health. 7- Bibliography Anderson, H.R . (1996). Air pollution and Daily Mortality in London. Pp. 74-81. Balamugesh, T. & Behera, D. (2005). Indoor Air Pollution as a Risk Factor for Lung Cancer in Women. Journal of Assoc Physicians India, Vol.53. Pp. 90-92. Retrieved on 5th 01, 2015 from Belanger,K., Gent, J. F., Triche, E. W., Bracken, M. & Leaderer, B. P. (2005). Association of Indoor Nitrogen Dioxide Exposure with Respiratory Symptoms in Children with Asthma. Billionnet, C., Gay, E., Kirchner, S., Leynaert, B., Annesi-Maesano, I. (2011). Quantitative Assessments of Indoor Air Pollution and Respiratory Health in a Population-Based Sample of French Dwellings. Environ Res. Vol.111. Pp. 425-434. Crown, (2012). Improving the energy efficiency of buildings and using planning to protect the environment. 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