# Learning objectives By the end of this chapter you will be able to: • understand the types of environmental hazard and how they affect health • describe the basic requirements for a healthy environment and understand the importance of healthy settings • apply frameworks used to describe complex environmental causes of health effects • assess the role of health evidence in environmental decision-making # Key terms [[Health impact assessment (HIA)]]: A means of assessing the health impacts of policies, plans and projects in diverse economic sectors using quantitative, qualitative and participatory techniques. [[Precautionary principle]]: A principle that advocates the use of prudent social policy in the absence of comprehensive empirical evidence in an attempt to solve a problem. It enables a rapid response in the face of a possible danger to human, animal or plant health, or to protect the environment. In particular, where scientific data does not permit a complete evaluation of the risk, recourse to this principle may, for example, be used to stop the distribution or order withdrawal from the market of products likely to be hazardous (EU definition, from EUR-lex 2011). # Environmental quality and health ## Environmental hazards Another way to categorize hazards is to consider the mechanisms by which humans come into contact with them (exposure route). The media that carry hazards include: • water (used for drinking, recreational activities or agricultural activities such as irrigation); • air (indoor and outdoor pollution); • soil (also through consumption of food grown in contaminated soil); • food (chemical and biological contamination); • special environments that potentially carry hazards, such as agricultural environments, water resources or wetlands. ## Hazards and risks A hazard, in this book, is defined as ‘a factor or exposure that may adversely affect health’ A risk is defined as ‘the probability that an event will occur, e.g. that an individual will become ill or die within a stated period of time or age; the probability of a (generally) unfavourable outcome’ ## Environmental risk transition As countries undergo economic development, there are associated changes in potential environmental hazards which can lead to new health risks in the absence of sound environmental management (see Chapter 3; Smith and Ezzati 2005). This change in risk profile is referred to as the ‘risk transition’, and is further defined in this book as ==the process by which societies move from exposure to traditional hazards to exposure to modern hazards==. Traditional hazards such as lack of access to water of sufficient quality or quantity, or lack of adequate food supply are still present in LMICs, while modern hazards such as lack of exercise, high fat diet and high levels of road traffic become more prevalent with increasing economic growth and specifically with increasing urbanization and industrialization, and the move away from agricultural to technology based economies. ^7dd029 | Traditional hazards | Modern hazards | | ------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------- | | Lack of access to safe drinking water | Water pollution from populated areas or intensive agriculture | | Inadequate or poor quality housing and shelter | | | Inadequate basic sanitation (household and community) | Urban air pollution from motor cars, coal | | Food contamination with pathogens, dietary deficiency | Food contamination with pesticides; poor diet leading to obesity | | Indoor air pollution from cooking and heating using biomass fuel (wood, animal dung and crop residues) | Tobacco smoke, power stations and industry; traffic accidents | | Disease vectors (mainly insects and rodents) | Emerging and re-emerging infectious disease hazards | | Infectious agents | | | Inadequate solid waste disposal | Solid and hazardous waste accumulation | | Occupational injury hazards in agriculture and cottage industries | Occupational innjury from industry (e.g. large-scale machinery) | | Wildlife and domestic animals | Chemical and radiation hazards from introduction to new technologies | | Natural disasters, including floods, droughts and earthquakes | | # Basic requirements for a healthy environment ## Healthy settings [[Health for All]] strategy, more specifically, the [[Ottawa Charter for Health Promotion]] > According to the Ottowa Charter of 1986, ‘[[health is]] created and lived by people within the settings of their everyday life; where they learn, work, play, and love’. As such, healthy settings can be healthy cities, healthy workplaces, healthy schools, healthy homes, etc. There will be more discussion on the requirements for healthy housing in Chapter 6 and for healthy urban environments in Chapter 9. # Health in environmental decision-making The [[DPSEEA framework]] was developed by the WHO to understand the linkages between environment and health, to support decision-making. The framework has been widely used in European and international health assessments (Corvalán et al. 2000). Figure 2.3 shows the framework. The range of causes that should be specified include the more immediate causes (exposures to environmental hazards) to more upstream causes of environmental hazards (such as environmental pressures caused by, e.g., economic or population growth). The immediate causes are termed proximal and the upstream causes distal. • Driving forces or ‘drivers’ are the social, demographic and economic developments in societies (e.g., economic growth, urbanization) and the corresponding changes in lifestyle factors, overall levels of consumption and production patterns. Drivers function through human activities which may intentionally or unintentionally exert pressures on the environment. • The pressures exerted by society may lead to unintentional or intentional changes in the state of the environment, such as levels of pollution in the water, air or soil. • Factors such as human behaviour and lifestyle choice will influence individual exposure to environmental hazards. These exposures lead to effects on human health which include mortality and morbidity outcomes. • Action can be taken by decision-makers at any stage along this causal chain. ![[DPSEEA framework to air pollution.png]] ## [[Environmental justice]] In response to the increasing awareness that the impact of the environment on [[health is]] not equal among all sectors of the population, the concept of environmental justice has developed. The environmental justice movement began in the USA in 1982 when North Carolina selected the Shocco township (which has a predominantly non-white population with a high proportion below the poverty line) to host a hazardous waste landfill containing chemically contaminated soil. Historically, environmental discrimination has occurred with respect to waste disposal, manufacturing (location of ‘dirty’ industries) and energy production (Land Loss Prevention Project 2006–13). Environmental justice focuses on the fair distribution of environmental benefits and burdens (distributive justice) and meaningful participation in decision-making processes (procedural justice). It represents a developing approach in which what constitutes truly healthy, liveable, sustainable and vital communities is central (Lee 2002). Effective action to redress inequitable distributions of environmental burdens (such as pollution, industrial facilities and crime) may need to focus beyond exposure and consider social, economic and cultural factors, as introduced in Chapter 1 (Lee 2005). Figure 2.4 shows the pathways by which exposure to environmental hazards for different groups can lead to health inequalities. ## Risk assessment Disease burden can be expressed in deaths, incidence or in disabilityadjusted life years (DALYs) (see McKee et al. 2011b). The latter measure combines the burden due to death and disability in a single index. ==The DALY relies on an acceptance that the most appropriate measure of the effects of chronic illness is time, both time lost due to premature death and time spent disabled by disease==. One DALY, therefore, is equal to one year of healthy life lost. Using such an index permits the comparison of the burden due to various environmental risk factors with other risk factors. ## Economic considerations and externalities Externalities are social benefits and costs that are not included in the market price of an economic good (Last 2001). Individuals tend not to include the full environmental costs of activities in their decisions as to how much of a resource to ‘consume’. When deciding, for example, how far to drive or how much coal to use to heat their homes, ==individuals tend only to consider the ‘private’ costs, such as fuel, and do not consider costs external to themselves (e.g. of polluting the atmosphere)==. Public goods such as clean air are not traded on markets and therefore do not have market prices. This is because they belong to everybody and nobody – there is a lack of clearly defined property rights and it is not possible to prevent someone from consuming them if they do not pay for them. In the absence of regulation, none of this pollution damage is paid for by the consumer, instead it is paid for by society in terms of ill health and environmental degradation. This can be addressed by policy interventions such as the ‘polluter pays’ principle – in which the marginal social cost (marginal private cost + marginal external cost) is equal to the price, and can be achieved by the use of such economic policy instruments as pollution taxes or tradeable permits. ## Action to protect health from environmental hazards Managing environmental risks requires us to develop the most appropriate strategies, policies or measures in response to an environmental hazard, taking into account all regulatory, political, environmental, engineering and social factors which might be relevant. Historically, action to protect the environment has focused on eliminating or reducing significant hazards. The DPSEEA framework discussed above shows that action to prevent environmental hazards can be taken at all levels of policy (see Figure 2.3). Upstream prevention is likely to be more effective in protecting health, but is often more difficult to do (see Chapter 7 for an example relating to transport and health). It has been argued that the types of precautionary action should be multiple in nature and case-specific (Martuzzi and Tickner 2004), depending on: • the nature of the risk, its level of uncertainty, magnitude and reversibility; • who is exposed (e.g. disproportionately affected or highly vulnerable communities); • issues of technological and economic feasibility, benefits, proportionality and non-discrimination; • preventability of risk; • social values.