Environment and Public Health

Environment and Public Health

2F: Disease Causation and Diagnostics in Public Health - Environment

• Growing focus on the impact of human activity on the environment, with climate change considered a major threat.

• The environment profoundly impacts health: living/working locations, air, water, and food.

• Public health specialists must understand:

  • Human impact on the environment (pollution, climate change).

  • Environmental effects on humans (environmental determinants of health).

• Understanding policy levers to improve the environment and reduce environmental hazards.

2F.1: Environmental Determinants of Disease

• Environmental health traditionally focused on short-term hazards (chemical, biological, physical agents).

• Now, the environment includes all external factors: diet, housing, water quality.

• Dahlgren and Whitehead’s rainbow model includes all layers except 'age, sex, and constitutional factors' as environmental determinants.

• Environmental determinants are categorized in Table 2F.1.

Environmental Burden of Disease

• Most diseases result from the interaction of heredity (genetic) and environmental factors.

• The burden attributable to environmental factors depends on the definition of 'environmental determinants'.

• Environmental risk factors directly account for approximately 10-15% of the global burden of disease [61, 62].

2F.2: Risk and Hazard

• Environmental hazards: factors that can harm health (pollution, chemicals, radiation, extreme temperatures).

• Environmental risk: probability of an unfavorable event (radiation exposure, storm, flooding) $*$ consequences of that event (Box 2F.1).

• This definition of risk differs from the epidemiological definition.

$Risk = Probability \times Consequences$

• Risk management focuses on minimizing hazard exposures (occurrence and impact).

Environmental Justice

• Exposure to environmental risk factors is greatest among deprived people, despite wealthier people causing more pollution/carbon emissions.

• This is environmental injustice, causing health inequalities.

• Examples:

  • Local: Wealthier people cause more pollution from cars; deprived groups near busy roads suffer disproportionately.

  • Global: Developed countries release more carbon dioxide; developing countries suffer the worst climate change effects (desertification, flooding).

Risk Management

• Important in community and occupational settings.

• Two key stages: risk assessment (characterization) and risk management (Table 2F.2).

• Risk characterization estimates adverse health effects in a defined population:

  • Hazard identification.

  • Dose-response assessment.

  • Exposure assessment.

• Risk management limits a hazard's effects on health:

  • Risk evaluation.

  • Risk perception and communication.

  • Control of exposure.

  • Risk monitoring.

Risk Communication

• Determines issue acceptability to the public, relies on understanding risk concepts and communicating honestly.

• Poor communication damages public trust.

• Sandman [64] defines risk as the perceived likelihood of an event.

$Risk = Hazard + Outrage$

• Risk communication depends on managing public outrage appropriately (neither frightened nor apathetic).

• Sandman listed nine factors affecting outrage (Table 2F.4).

• Public health specialists improve communication by:

  • Considering factors influencing risk perception.

  • Understanding viewpoints.

  • Using appropriate media/language for relevant information.

2F.3: Climate Change

• Effects of global warming and climate change.

• Anthropogenic (human-induced) climate change is mainly caused by increased levels of greenhouse gases (carbon dioxide (CO2) and methane).

• Greenhouse gases trap warmth reflected off the earth.

• Increased CO2 levels result from deforestation and fossil fuel combustion.

• Increased atmospheric energy leads to more extreme events: storms, heat waves, cold temperatures, rainfall, rising sea levels, and floods.

• The UK expects warmer wetter winters and hotter dryer summers [65].

• Temperatures rose from 1906 to 2005 by $0.74°C$ on average globally.

Effects of Climate Change on Health

• Health effects may be direct or indirect (Box 2F.2).

Responding to Climate Change

• Involves mitigating climate change (limiting greenhouse gas emissions) and adapting to the effects.

Mitigation

• Reducing CO2 emissions is most important.

• Methods:

  • Using less energy from fossil fuels.

  • Behavior change (active travel).

  • Energy efficiency measures (housing insulation).

  • Using alternative energy sources (renewable energy or nuclear power).

• Legislation is vital (e.g., Kyoto Protocol) and preventing deforestation.

• Other mechanisms: pollution abatement, CO2 scrubbing, and geo-engineering methods (carbon capture and storage, reflective particles in the atmosphere).

Adaptation

• Mechanisms to adapt and limit effects on public health:

  • Infrastructure developments (flood barriers, shade, passive cooling).

  • Information dissemination (heat wave warning systems).

  • Vaccination against infectious diseases.

  • Protection from the sun ('slip, slap, slop' campaigns).

  • Preparing for increased migration.

Box 2F.2 Direct and indirect effects of climate change

Box 2F.3 The United Nations framework convention on climate change

2F.4: Principles of Sustainability

• Environmental sustainability balances present needs with future generations.

• Involves long-term considerations about resource use.

• Current resource use and pollution rates are unsustainably high.

• Examples of unsustainable exploitation:

  • Global reduction in productive soils for agriculture.

  • Depletion of ocean fisheries.

  • Use of fossil fuels causing global warming.

UK Department for Environment, Food and Rural Affairs (DEFRA)

• Adopts a broad view of sustainability (environmental, social, and economic developments).

• Outlines five principles of sustainable development (Table 2F.5).

Table 2F.5 Principles of sustainable development - includes environmental limits, healthy and just society, good governance, responsible use of science, sustainable economy

2F.5: Housing and Water

• Health problems are associated with poor housing and home conditions, inadequate water supplies, flooding, poor sanitation, and water pollution.

Housing and Health

• Complex relationship, where individual exposures don't always relate directly to specific morbidities.

• Poor housing correlates with other forms of deprivation (poor education, unemployment, ill health, social isolation).

• Housing impacts both physical and mental health.

• Specific hazards and health effects are in Table 2F.6.

• Neighborhood amenities impact health (transport, shops, open spaces) affecting safety, isolation, social cohesion, and crime.

• Government policy recognizes benefits of open spaces in enabling local people to be active and to maintain social links.

• Local authorities consult on plans affecting open spaces and sports facilities.

Homelessness

• Strong associations between homelessness and health (drug/alcohol abuse, mental health problems, infectious diseases like TB and hepatitis).

• Homelessness includes sleeping rough or temporarily sleeping in inadequate spaces.

Land Contamination

• May occur in brownfield (abandoned industrial land) or greenfield sites (undeveloped land) (Table 2F.7).

• Legal definition: Part 2A of the Environmental Protection Act 1990 requires 'significant harm' to be caused by the contamination.

• Owner/developer pays for remediation.

• Local authorities identify contaminated land.

• Iterative risk assessments are conducted (Table 2F.8).

ENG

• First step: pathway receptor model outlining people at risk and exposure pathways.

Water and Health

• A vital resource for agriculture, industry, drinking, food preparation, and sanitation.

• Quantity and quality strongly influence disease risk.

• Availability is an issue globally, including the United Kingdom.

Water Monitoring and Control

• The Drinking Water Inspectorate (DWI) regulates water quality in the UK.

• Water undergoes tests for quality characteristics (Table 2F.9).

• Up to 1 million UK households have private drinking water supplies (PWS), regulated since 2009.

• Arsenic in PWS can cause lesions and cancers.

Water Pollution

• Damages aquatic life and makes drinking water treatment difficult.

• Common pollutants are summarized in Table 2F.10.

Water Supply

• Availability is promoted through:

  • Monitoring water levels.

  • Requiring long-term water resource plans.

  • Issuing abstraction licenses.

• At the domestic level:

  • Hosepipe bans.

  • Short showers.

  • Short-flush toilets.

  • Fixing dripping taps.

  • Reusing water.

  • Collecting rainwater.

  • Fitting water meters.

Flooding

• Numerous risks to health:

  • Drowning.

  • Injury.

  • Mental health.

  • Water contamination.

  • Lack of water and electricity.

  • Disrupted transport.

  • Increased infectious disease risk.

  • Social impacts.

Water and Health in Developing Countries

• Inadequate supplies remain a major problem (15-20% of the world, mostly Asia and sub-Saharan Africa).

• Poor water security and sanitation result from disasters or pollution.

• Interventions can also exacerbate health problems (e.g., malaria with irrigation channels).

• Inadequate water leads to infectious diseases due to:

  • Ingestion of faecal contamination.

  • Water-based microbial agents.

  • Water-related vectors.

Sanitation

• Refers to facilities or services for safe disposal of human waste.

• Problems include odor and insects.

Waste Disposal

• The waste hierarchy (EU framework) orders waste disposal options (Figure 2F.1).

• Most desirable: reduce waste.

• Then reuse, recycle.

• Least desirable: incineration or landfill.

• Manufacturing can adopt low waste processes, and households can compost.

• Recycling has increased substantially in the UK.

Incineration

• About 19% of UK waste in 2011/2012.

• Produces fewer harmful chemicals but is questionable environmentally.

• Recycling uses less energy; incinerator ash contains toxins.

Landfill

• Around 38% of waste in Britain.

• Harmful effects:

  • Rotting rubbish emits explosive gases.

  • Noxious liquids risk polluting waterways.

  • Additional nuisances.

Hazardous Waste

• Certain items risk causing harm when discarded (batteries, paint, healthcare waste).

• Inappropriate disposal contaminates the land.

Regulation

• The Environment Agency (EA) and the Scottish Environment Protection Agency (SEPA) enforce waste management licensing in the UK.

2F.6: Monitoring and Control of Environmental Hazards

• Methods for monitoring and control of environmental hazards including food and water safety, atmospheric pollution and other toxic hazards, noise, and ionising and electromagnetic radiation.

• Environmental hazards must be monitored to reduce exposure risks.

• Different monitoring systems are used depending on the hazard, but all systems require surveillance data (Table 2F.11).

Food Safety

• See Section 2F.5 for water safety.

• Food affects health through nutrition and toxicological safety.

• Contaminants may be biological, chemical, or radioactive (Table 2F.12).

• The WHO and the Food and Agriculture Organization (FAO) set standards for food additives and pesticides.

• The Food Standards Agency (FSA) monitors contamination levels in food.

• Food quality may be improved at all stages between production and consumption (Table 2F.13).

Atmospheric Pollution

• Air pollution may be indoor or outdoor (atmospheric or ambient).

Indoor Air Pollution

• Pollution from solid-fuel stoves is a major problem in the developing world.

• Improved insulation decreases ventilation, exacerbating the problem.

• Passive exposure to cigarette smoke was another major problem; many countries have banned it now.

Atmospheric Air Pollution

Monitoring and Control (EU)

• Attempts have been made to quantify the mortality and morbidity associated with vehicle pollution in European cities (see COMEAP [71]).

Monitoring and Control (UK)

• Air quality is monitored routinely across the UK.

• DEFRA's UK-AIR information resource provides information on air pollution nationally and regionally and issues forecasts.

• The government’s Air Quality Strategy sets acceptable levels of major pollutants.

• Local authorities assess air quality and produce action plans.

• There are regular exceedances of NO2 and PM10 standards.

• The European Commission considers legal action against DEFRA for failing to meet EU air quality regulations.

• The UN Economic Commission for Europe supports countries' efforts to reduce pollution.

• The UN has negotiated treaties requiring signatory countries to reduce pollution (e.g., the Kyoto Protocol).

Noise

• Unwanted sound that causes discomfort, leading to stress, sleep disturbance, deafness, poor school performance, and cardiovascular disease.

• Noise may originate from transport, industry, neighbors, or the workplace.

• The Noise at Work Regulations 2005 ensure that workplaces monitor noise and take action if levels reach 80 decibels.

• Legislation exists to restrict noise at night in local communities.

Radiation

• Ionising - has the ability to ionize atoms and is characterized by high energy

• Non-ionising - does not produce sufficient energy to ionize particles.

Ionising Radiation

• The most common source is radon, a gas from uranium in rocks and soils.

• Accounts for about half of UK residents' radiation dose.

• Higher levels in South West England increase lung cancer risk.

• Householders should monitor and reduce radon levels (not exceed $200 Bq/m^3$).

• Actions involve improving ventilation.

• Naturally occurring constitutes 84% of exposure

• Healthcare accounts for 15%

• Industry accounts for <1%

Measuring Radiation

• Quantified using varied methods and units based on the amount of radiation released, absorbed dose, or risk to health. These are the principal methods:

  • Becquerel (Bq) - Amount of radioactivity in a material (unit relates to disintegrations per second).

  • Gray (Gy) - Absorbed dose: Energy deposited in each gram of tissue (joules per kg), indicating acute radiation damage to organs.

  • Sievert (Sv) - Risk of exposure or effective dose: Risk of cancer from chronic or low doses of radiation.

Health Effects of Ionising Radiation

• Depend largely on dose. Health effects are likely over 1 Gy (early and late):

• Early: acute radiation sickness, sterility, skin erythema.

• Later: cancer, hereditary defects, organ damage.

• A single exposure over 5 Gy is likely to be fatal.

Monitoring and Control

• Policy set by EU directives.

• Government bodies involved:

• The Centre for Radiation, Chemical and Environmental Hazards of Public Health monitors and researches

• The EA is a major source of guidance and regulation

• DEFRA is responsible for implementing legislation and regulating chemicals and environmental threats to health.

Nonionizing Radiation

• Sunlight consists of UVA and B radiation (Table 2F.16).

• Exposure increases the risk of cataracts and skin cancer.

• Electromagnetic fields (EMFs) are potentially associated with cancer; mobile telephones and power lines are major concerns

2F.7: Use of Legislation in Environmental Control

• Control of pollution/waste requires effective legislation due to conflict between economic priorities, protecting the environment, and human health.

• Tension for small businesses and developing countries (lacking information, expertise).

• Environmental hazards are seldom limited geographically.

• Legislation to tackle pollution/waste should be international.

• Within the EU, legislation may be primary (treaties, directives) or secondary (regulations, instruments).

European Union Legislation

• Based on polluter pays and the precautionary principle (Table 2F.18).

• Aims to restrict pollution/emissions and ensure safe waste disposal (Table 2F.19).

• Compliance can be enforced through:

• Inspections

• enforcement

• suspension

• Penalties (fines, imprisonment).

Regulatory Agencies (UK)

• The EA regulates large industrial processes; local authorities regulate smaller industries.

• Other agencies: Health and Safety Executive, DWI, Trading Standards, FSA.

• Environmental health officers enforce regulations.

2F.8: Health and Safety at Work

• Appreciation of factors affecting health and safety at work (including the control of substances hazardous to health).

• Factors include the work environment, occupational equipment, and other employees.

• Improving occupational health benefits both employees and employers (health effects, financial costs).

• Types of workplace exposures are described in Table 2F.20.

• Compliance with environmental legislation varies due to varied awareness, standards, penalties, etc.

Table 2F.20 Occupational hazards

Prevention

• Interventions to minimize exposure can target the worker (education, PPE) and the work environment (safe processes, monitoring).

Control of Substances Hazardous to Health (COSHH)

• Regulations [74] limit exposures to hazardous substances:

• Substances used directly in work activities,

• Substances generated during work activities

• Naturally occurring substances

• Biological agents

• Employers must:

• Assess the risk

• decide on precautions

• Control exposure

• Maintain controls

• Monitor exposure

• Undertake health surveillance

• Ensure training

• Prepare for incidents.

Other Occupational Health Regulations

• Pertinent regulations include:

• Reporting of Injuries

• WHO occupational limits

• European Working Time Directive regulations

Occupational Health Agencies

• Key agencies are listed in Table 2F.21.

Safety at Work Audits

• Procedures to monitor and control health and safety factors at work are considered in sequential steps (Table 2F.22).

• The effects of occupation on health vary according to:

• Type of occupation

• Personal risk factors

• Levels of social support.

• There are general health benefits to being in work, but certain occupations expose employees to particular risks.

Unemployment

• Being out of work is associated with adverse physical, mental, and social effects.

• Phenomena are related to the length of time spent unemployed.

• Ill health and healthcare use is also associated with job insecurity.

• There are consequences from unemployment on the individual, on families, and on society at large (Table 2F.23).

2F.10: Health Impact Assessment for Environmental Pollution

• See Section 1C.17 for details on health impact assessment (HIA) and environmental impact assessment (EIA).

• In considering the health impact of pollution, the risk assessment principles should be applied.

• The Environmental Impact Directives [76] do not legally require mandatory HIAs

• The UK Planning Act [77] requires assessments on health.

2F.11: Transport Policies

• Transport policies acknowledge the benefits of transport and accessibility (employment, goods, social activities).

• It is also important to recognize health benefits with active transport (walking or cycling)

• Risks associated with non-active methods:

• Air pollution

• noise pollution

• collisions

• Effects on cohesion.

Sustainable Transport

• Policies promote forms of transport that have the potential for maintaining wellbeing in the long term (environmental, economic, and social dimensions).

• Focus on environmentally friendly transportation, taxation, reducing car usage and emissions, promoting sustainable forms.

Environmentally Friendly Transportation

• Alternatives to cars encouraged by sustainable transport policies (Table 2F.24).

• Active forms of transport increased physical activity, reduce air pollution, and greenhouse gas emissions, and reduce noise.

• Studies in European settings have shown that the health benefits of cycling to the individual outweigh the risks [79].

Taxation

• Can be used to encourage industry and consumers to adopt more fuel-efficient vehicles.

Reducing Car Usage

• This can be achieved through:

• Levies/taxes for road use

• Parking restrictions and charges

• Subsidizing public transport costs

• Encouraging car sharing

• Reducing freight transport by road

Reducing the Environmental Impact of Transport

• Carbon-offsetting initiatives compensate the environment for carbon dioxide emissions.

• Processes that emit carbon dioxide match with projects that reduce the emission levels

• Carbon capture relies on finding locations to store carbon dioxide so that it does not reach the atmosphere.

Emissions Trading Schemes

• Provide economic incentives for industrial polluters to reduce their emissions.

Table 2F.24 Alternative means of transportation