L8 Enviornmental health and Public health & climate change

What does environmental health comprise of ? What are the determinant of environmental health ?

Environmental health comprises 包括 those aspects of human health, including quality of life, that are determined by physical, biological, social, and psychosocial factors in the environment (WHO).

It also refers to :

• the theory and practice of assessing, correcting, controlling, & preventing those factors in the environment that can potentially affect adversely the health of present and future generations (WHO).

Environment = All of the external factors affecting an organism.

These factors including biotic and abiotic factors, what are they ?

• living organisms (biotic factors) or nonliving variables (abiotic factors), such as

  • temperature,

  • rainfall,

  • day length,

  • wind, and

  • ocean currents.

How can an ecosystem be formed ?

The interactions of organisms with biotic and abiotic factors form an ecosystem.

Suggest examples of environmental factors that might adversely impact human health or the ecologic balances to long-term human health and environmental quality, which need to be protect against.

air,
food
water contaminants (e.g. lead, copper)

radiation,
toxic chemicals (e.g. pesticide)
wastes,
disease vectors,
safety hazards, and
habitat alterations

What are the importances of humans and the environment ?

• Focuses on the relationship between the environment and human health.

  • The physical environment, our habitat is an important determinant of human health.

• Protection of the environment and preservation of the ecosystems are extremely important in preventing human illness.

What is Minamata Disease ?

Methyl Mercury poisoning

What is Seveso disaster about ?

Leak of toxic gas (TCDD)

• The most toxic type of Dioxin: Type 1 carcinogen

• Long-lasting effects on thyroid function in babies

What is Bhopal, India (1984) disaster about ?

16.5 tons of toxic pesticide released

What is Chernobyl, USSR (1986) disaster about ?

Nuclear Reactor Accident

Give examples of clinical manifestations due to of nuclear power plant accident (6)

• Lung diseases

• Reproductive effects

• Teratogenic effects

• Neurologic effects

• Immunosuppression and hypersensitivity

• Cancer

What is Moya Moya Disease ?

• mutations in the RNF213 gene

• a rare, progressive cerebrovascular disorder where the internal carotid arteries at the base of the brain narrow, restricting blood flow and causing "puff of smoke" collateral vessel formation

suggest and explain examples of Water-borne diseases

• Water-borne diseases are diseases that are transmitted in drinking water,

• Arsenic contaminated water

• Boreholes are often drilled to access groundwater sources for drinking water, increase the risk:

  • e.g. polio virus, hepatitis A virus, Salmonella, Shigella, cholera, amoebic dysentery,Giardia, & Cryptosporidium.

suggest and explain examples of food-borne diseases

Food-borne agents (bacteria) transmitted in or on food, e.g.

• Salmonella, serotype enteritis, Escherichia coli 0157:H7

Suggest ways to protect against food-borne disease

sanitarians from local health departments routinely inspect

• food service establishments (restaurants) and

• retail 零售 food outlets (supermarkets)

• to verify that food is being stored and handled properly.

suggest and explain examples of vector-borne diseases

• are those transmitted by insects or other arthropods

  • St. Louis encephalitis

  • La Crosse encephalitis

    • transmitted by mosquitoes and plague and murine typhus transmitted by fleas.

Improper environmental management can cause vector-borne disease outbreaks.

What is the purpose of using pesticides ? also suggest examples

kill non-target organisms as well as the target, or pest species. the wise use of pesticides can protect human health and agricultural crops.

• Examples of categories of pesticides:

  • Herbicides

  • Insecticides

What is the chronic effects of using pesticides ?

long-term exposure is linked to cancers (e.g., leukemia, lymphoma), developmental delays, reproductive harm (e.g., infertility), neurotoxicity, and endocrine disruption.

• Vulnerable groups such as children and agricultural workers face heightened risks

List the environmental impact of pesticides

1. Climate change

2. Food security risks

3. Global spread of contaminants

Explain how does pesticides lead to climate change

The production and disposal of pesticides contribute significantly to greenhouse gas emissions.

Additionally, pesticide-related biodiversity loss undermines ecosystem services critical for climate resilience.

Explain how does pesticides increase food security risks

Pollinator declines caused by insecticides threaten crops reliant on pollination (e.g., fruits, nuts).

Herbicide contamination of water sources also impacts irrigation systems necessary for agriculture

Explain how does pesticides become global spread of contaminants

Pesticide residues are detected worldwide in drinking water sources, including wells in countries like the U.S., Canada, China, Japan, Brazil, and Vietnam. This highlights the pervasive 普遍的 nature of contamination

Suggest the disease associated with environmental tobacco smoke and classification

• Diseases associated with ETS include

  • Increased risk of cancer

  • cardiovascular and stroke risks

  • adverse effects on children and pregnancy

• The US Environmental Protection Agency (EPA) has classified ETS as a Class A carcinogen

Explain how does environmental tobacco smoke increase risks of cancer

Secondhand smoke contains over 7,000 chemicals, including at least 70 known carcinogens. It is a proven cause of lung cancer in nonsmokers, increasing their risk by 20-30%. There is also evidence linking ETS to other cancers, such as those of the larynx, nasopharynx, and breast

Explain how does environmental tobacco smoke increase cardiovascular and stroke risks

ETS exposure has immediate harmful effects on the heart and blood vessels, significantly increasing the risk of coronary heart disease and stroke in nonsmokers. Studies estimate a 25-30% increased risk for heart disease and a 20-30% increased risk for stroke due to secondhand smoke exposure

Explain how does environmental tobacco smoke cause adverse effects on children and pregnancy

Children exposed to ETS are at higher risk for respiratory infections (e.g., bronchitis, pneumonia), asthma attacks, ear infections, and slowed lung development. In infants, ETS exposure is associated with sudden infant death syndrome (SIDS).

Additionally, exposure during pregnancy can lead to complications such as low birth weight and preterm birth

Suggest the health problems associated with over exposure to lead

• anemia, birth defects, bone (& teeth) damage, neurological damage, kidney damage, and others.

Exposure is by ingestion and inhalation.
Children are particularly at risk from eating peeling lead paint.吃掉剝落的含

Occupational exposure is a major source of lead intake for adults.

List 4 environmental health principles

• Everything is Connected to Everything Else

• Everything has to go somewhere

• The solution to pollution is dilution

• Today’s solution may be tomorrow’s problem

Explain the environmental health principle: Everything has to go somewhere

• Once waste products are generated, they must be disposed of in one of three ways:

  • Incineration

  • Water discharge

  • Landfill or burial in soil

• Each options presents problems in changing the waste product to a less toxic form, so prevention is desirable.

Explain the environmental health principle: The solution to pollution is dilution

Exposure to most pollutants is harmful in larger doses, therefore dilution is often to solution.

Waste products can be diluted by moving them to larger mediums. E.g.,

• higher smokestacks 更高的煙囪 to dilute pollutants in atmosphere,

• pumping sewage into ocean, etc..

  However, planet’s capacity to assimilate by‐products of human civilization is not limitless.

Explain the environmental health principle: Today’s solution may be tomorrow’s problem

More unknown than known about many environmental health effects.

Decisions made on best information available at time decision was made are later found to be harmful:

• Garbage in landfills caused groundwater contamination

• Buried gasoline or fuel tanks leaked over time

• Increasing number of chemicals being produced poses increasing problem as long‐term effects are largely unknown.

What is the main cause of pollutants ?

• All pollution is result of population growth

• Population growth is MOST significant global environmental threat

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*Pollutants can provide energy or nutrients that increase the productivity of the ecosystem when rate of input is moderate.

According to WHO, which pollution is the leading cause for cancer ?

• Air pollution may cause breathing, eyes and skin problems

• The WHO has classified outdoor air pollution as a leading cause of cancer humans.

• Air pollution was already known to increase the risk of respiratory and heart diseases.

what is PM2.5

While particles with a diameter of 10 microns or less, (≤ PM10) can penetrate and lodge deep inside the lungs, the even more health-damaging particles are those with a diameter of 2.5 microns or less, (≤ PM2.5).

• Chronic exposure to particles contributes to the risk of developing cardiovascular and respiratory diseases, as well as of lung cancer.

what are the sources of PM2.5 ?

Sources may emit PM directly into the environment or emit precursors such as sulfur dioxide (SO2), nitrogen dioxide (NO2), and volatile organic compounds (VOCs), which are transformed through atmospheric chemistry to form PM.

Relationship between air pollution and cancer (3)

• the International Agency for Research on Cancer (IARC), classifies outdoor air pollution as carcinogenic to humans (Group 1).

• increases the risk of cancer, particularly lung cancer.

  • Particulate matter (PM), a major component of air pollution, has been separately classified as a Group 1 carcinogen due to its strong link with lung cancer incidence and mortality. Studies indicate that long-term exposure to PM2.5 (fine particulate matter) significantly raises the risk of developing lung cancer, even after accounting for other factors such as smoking

• Additionally, there is a positive association between air pollution and an increased risk of bladder cancer

what is the health implications for low API (Air pollution Index) ?

low = 0-25

Health implications not expected.

what is the health implications for medium API (Air pollution Index)?

medium = 26-50

Health implications not expected for the general population.

what is the health implications for high API (Air pollution Index)?

high = 51-100

Few or none in the general population may notice immediate health effects. Long-term effects may, however, be observed if you are exposed to such levels persistently for a long time.

what is the health implications for very high API (Air pollution Index)?

very high = 101-200

People with existing heart or respiratory illnesses may notice mild aggravation of their health conditions. Generally healthy individuals may also notice some discomfort.

what is the health implications for severe API (Air pollution Index)?

severe = 201-500

People with existing heart or respiratory illnesses may experience significant aggravation of their symptoms and there will be also widespread symptoms in the healthy population. These include eye irritation, wheezing, coughing, phlegm and sore throat.

what is the differences between Air quality Health Index (AQHI) and Air pollution index (API) ?

To provide more timely and useful air pollution information to the public, the Environmental Protection Department (EPD) launches the Air Quality Health Index (AQHI) to replace the Air Pollution Index (API) from 30 December 2013.

The AQHIs are reported on a scale of 1 to 10 and 10+ and are grouped into five health risk categories

How is Air quality Health Index (AQHI) calculated ?

AQHIs are determined using the cumulative health risk from the 3-hour moving average concentrations of four key air pollutants:

- Ozone (O3)
- Nitrogen Dioxide (NO2)
- Sulphur Dioxide (SO2)
- Particulate Matter (PM2.5 / PM10)

The relative risk (RR) is the probability that a member of an exposed group will develop a disease relative to the probability that a member of an unexposed group will develop that same disease.

Explain why Because of air pollution, some schools in HK suggest children not to play outdoors still resulting children develop respiratory diseases

Homes with poor ventilation increase exposure to indoor air pollutants by increasing their concentrations and the length of exposure time.

Poor ventilation within homes has been shown to be associated with increased risk of asthma exacerbations and respiratory tract infections in children

List (+ explain) the household air pollution vulnerable groups

• Low socioeconomic status

• Women

• Children

• Elderly

• Immigrants / minorities

• Indigenous peoples 原住民

  Household air pollution causes more adverse impacts on women and children than men in developing countries.

  Women and children spend more time in kitchen and homes
  More vulnerable because of genetics and/or not empowered to change the environment.

Suggest interventions to reduce household air pollution and climate impact (4) (citizen level)

Basic technological Interventions / clean energy solutions

• Replacing traditional household solid fuel with lower-emission cookstoves 爐灶 and/or cleaner fuels

• Shifting away kerosene 煤油, e.g.Replace kerosene lamps to cut black carbon

• Improving the energy efficiency of homes and commercial buildings through insulation and passive design principles such as natural ventilation, lighting and solar heating

• Reduced Biomass Demand: Slows deforestation and boosts carbon absorption.

Cuts greenhouse gases and SLCPs.

Improves health, reduces deforestation, and mitigates global warming.

suggest interventions to improve air quality / reduce climate impact at system / policy level (9)

Standard Setting

• Adopt WHO global air quality guidelines

• Enforceable standards for output

Technology Forcing

• Stipulate 規定 technology that must be used Catalytic converters in cars & EVs

• All taxis and minibuses to use LPG Increase use of eco‐friendly technology

Economic Incentives

• Polluter pays principle

• Up‐front costs of waste disposal / recycling

• Tax credits 稅收抵免 for environmentally friendly practices

Information

• Labelling (pesticides) : Safe handling & environmental protection

• Reporting

Explain the general children’s health concerns regarding to pollution exposure

The potential for exposure and subsequent adverse health effects often increases for younger children compared with older children or adults.

Children are susceptible to

• developmental toxicity that an occur at levels much lower than those causing other types of toxicity.

Exposure to contaminants can cause permanent damage during critical growth stages.

What is the impact of climate change on health? (7)

Affects clean air, safe water, food supply, and shelter.

• Extreme heat:

  • Directly causes cardiovascular and respiratory deaths, especially in the elderly

  • Increases air pollutants like ozone, worsening heart and lung diseases.

  • Higher pollen levels trigger asthma, affecting 300 million people globally.

  • vectors growths —> disease

• Weather-related disasters

• Rising sea levels & extreme weather: Destroy infrastructure, force migration, and heighten risks of mental disorders and communicable diseases.

• Variable rainfall: Reduces freshwater availability, worsening hygiene and diarrhoeal diseases ; triggers droughts and famine 飢荒.

• Floods: More frequent and intense; contaminate water, spread diseases, and disrupt healthcare services. [最多人死]

• Food insecurity: Higher temperatures and erratic 不穩定的 rainfall reduce crop yields, worsening malnutrition

• Patterns of infection: Climatic conditions significantly influence water-borne diseases and those transmitted by insects, snails, or other cold-blooded animals.

  • Extend transmission seasons for vector-borne disease

  • Alter geographic ranges of diseases, such as schistosomiasis 血吸蟲病 in China.

Suggest 2 vector-borne disease that is climate-dependent

Malaria:

• Heavily climate-dependent.

• Transmitted by Anopheles (dusk/night biter) mosquitoes, causing over 400,000 deaths annually, primarily in African children under 5.

Dengue:

• Spread by Aedes (daytime biter) mosquitoes, highly sensitive to climate.

• Climate change is projected to increase global exposure to dengue.