Environmental Epidemiology

Air Quality Matters
Air pollution is a major health risk, contributing to asthma, allergies, lung disease, anxiety, and depression. Vulnerable groups include children, teens, older adults, pregnant women, and people with respiratory conditions. Pollution exposure varies by location, time of day, temperature, and weather.

Pollution sources include natural ones—wildfire smoke, pollen, pet dander, and mold—as well as human-made ones like vehicle exhaust, coal burning, garbage incineration, tobacco use, and wood or candle smoke indoors.

Protecting public health through cleaner air also lowers healthcare costs tied to heart attacks, strokes, asthma, lung cancer, respiratory hospitalizations, and premature deaths.

Health Risks of Air Pollution

Asthma attacks
Wheezing and cough
Shortness of breath
Lung tissue inflammation
Lung cancer
Cardiovascular problems
Higher infection risk
Premature death

Steps to Protect Your Lungs

1. Be air aware – Learn the Air Quality Index color codes to know when outdoor air may be unsafe.
2. Quit smoking – Get help through the TN Tobacco Quitline to stop tobacco use.
3. Reduce exposure in traffic – Use recirculated air when stuck in heavy congestion.
4. Avoid pollutants – Steer clear of smoke, exhaust, dust, and other airborne irritants.

Outdoor Air Pollutants
Outdoor air is polluted by emissions from vehicles and smokestacks, including particulate matter (PM), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and ozone (O₃). Allergens like pollen and mold also contribute. Ground-level ozone and particulate matter are among the most studied health risks.

Ground-level Ozone 
Ozone high in the atmosphere protects us, but at ground level it irritates the lungs. Formed when pollutants react with sunlight, ozone exposure can cause coughing, chest pain, throat irritation, wheezing, and shortness of breath—especially during exercise or outdoor activity in warmer months. People with asthma, bronchitis, or emphysema are at greater risk of severe symptoms and medical emergencies.

Particulate Pollution
Particulate matter includes dust, dirt, soot, smoke, and liquid droplets. Larger particles (PM10) are visible, but smaller ones (PM2.5) penetrate deeply into the lungs and pose greater danger. Exposure can cause eye, throat, and lung irritation, breathing problems, lung cancer, low birth weight in infants, and serious cardiovascular issues such as heart attacks.

Indoor Air Pollutants
Indoors, pollutants include tobacco smoke, fumes from paints and solvents, radon, carbon monoxide, formaldehyde, pet dander, mold, bacteria, pollen, and combustion gases. These can be especially harmful for people with asthma, COPD, or other respiratory conditions.

Air Quality Testing
The Tennessee Department of Environment and Conservation’s Division of Air Pollution directly serves 91 counties within the state by monitoring industries, conducting air pollution source visits, testing and monitoring air at the various stations set up across the state and other tasks. TDEC's Air Quality Monitoring plans and maps can be found at TDEC's Air Quality Monitoring site. If you live in Hamilton, Knox or Shelby counties, contact these local air programs for further air testing information.

Understanding Ammonia
At room temperature, ammonia is a colorless gas with a strong, pungent odor, familiar from cleaning products and smelling salts. It dissolves in water as aqueous ammonia, commonly found in household cleaners, but quickly turns back into gas when exposed to air.

Ammonia is widely used in fertilizers, refrigeration, and industry. It is often transported as anhydrous ammonia (compressed gas without water). Naturally, ammonia is formed in the atmosphere, in decomposing organic matter, and by bacteria in the intestines.

Ammonia’s Dangers
If you can smell ammonia, irritation to the eyes, nose, or throat is possible. Leave the area for fresh air and ventilate the space. If swallowed or splashed in the eyes, call the Tennessee Poison Center at 1-800-222-1222.

Ammonia in the Environment
Ammonia is short-lived in the environment and quickly absorbed by plants, animals, and bacteria as a nutrient. It does not build up in the food chain. For agriculture, it is applied to soils as fertilizer; for industry, it is shipped as compressed gas or used in refrigeration.

Exposure to Ammonia
Most people encounter low levels of ammonia in air, soil, and water. Higher exposures can occur from:

Household products (cleaners, waxes, smelling salts)
Leaks or spills at storage or transport sites
Fertilizer use on farms
Decaying manure in livestock operations
Industrial processes

Indoors, ammonia can also be released from pet urine or poorly maintained litter boxes. Workers in certain industries may need protective equipment. OSHA regulates workplace ammonia exposure.

Safer Cleaning Alternatives
Healthier cleaning options include vinegar mixed with water, baking soda, or citrus-based cleaners available in stores. These reduce chemical risks in the home.

How Ammonia Moves Through the Body
Ammonia enters through breathing, swallowing, or skin contact. Most ammonia from food and water changes into harmless substances and leaves the body in urine within days. High-level exposures (such as from spills) can cause serious health effects requiring medical care, though most people recover.

Health Effects of Ammonia

• Low levels: usually not harmful; irritation possible at noticeable odor levels (~5 ppm).
• Moderate exposure: eye, skin, throat, or respiratory irritation; coughing or wheezing.
• High exposure: burns, frostbite (anhydrous ammonia), or pulmonary edema. Very high levels (10,000 ppm) can be fatal.
• Long-term risks: no evidence of cancer or birth defects. People with asthma may be more sensitive.
• WHO and OSHA guidelines identify irritation thresholds between 25–50 ppm.

Responding to Ammonia Spills
Report suspected spills to the Tennessee Department of Environment and Conservation at 1-888-891-TDEC (8332).

For health concerns, contact your medical provider. For general questions, reach the Tennessee Department of Health’s Environmental Epidemiology Program at eep.health@tn.gov, 615-741-7247, or 1-800-404-3006.

Defining Asbestos
Asbestos is the name for six fibrous minerals with high strength, flexibility, resistance to heat and chemicals, and the ability to be woven. These properties led to widespread commercial use.

Sources of Asbestos
Asbestos comes from metamorphic rock deposits, with large reserves in the western U.S., the Carolinas, and small deposits in East Tennessee. The U.S. no longer mines asbestos; most is imported from Canada and Brazil.

Historical Uses of Asbestos
Asbestos appeared in more than 3,000 products, including insulation, flooring, roofing, ceiling tiles, appliances, clothing, brake pads, cement pipes, and potting soil.

Current Uses of Asbestos
Asbestos is still used in U.S. manufacturing, mainly in asphalt roofing (61%), gaskets (19%), and friction products (13%). These uses are regulated by OSHA. Some consumer products imported from other countries may contain asbestos, including vermiculite-based soil and insulation.

Asbestos in Tennessee
Asbestos is not a major public health concern in Tennessee today. Consumer products with asbestos are largely eliminated, and occupational exposure is controlled by regulation. The main risks come from old or imported products that are damaged and release fibers.

Health Effects of Asbestos
Asbestos is only harmful when fibers are inhaled. Disturbed materials release microscopic fibers that can lodge in the lungs, causing asbestosis, lung cancer, or mesothelioma. Risks are higher with long-term exposure and for smokers.

Understanding Mesothelioma
Mesothelioma is a rare cancer caused by asbestos fibers embedding in the lungs, heart, or abdominal lining. It often develops 10–50 years after exposure. About 3,000 U.S. cases are diagnosed each year, usually in older adults with occupational exposure. Prognosis is poor, though treatment can extend survival.

Levels of Danger
There is no safe level of continuous asbestos exposure. Health risks depend on dose and duration, often appearing decades later. Most low-level exposures do not cause illness, though secondhand exposure can occur from contaminated clothing or dust.

Locations of Asbestos Today
Asbestos-containing materials (ACM) are still present in older buildings, including homes and schools. Most homes built in the last 20 years are asbestos-free.

Identifying Asbestos in Homes
Asbestos cannot be identified visually; specialized microscopes and trained consultants are needed. Vermiculite, often contaminated with asbestos, can be recognized by its accordion-like shape.

Managing Asbestos in Homes
If ACM is intact, leaving it undisturbed is safest. Damaged material can be sealed or repaired. Removal is costly and risky, so licensed abatement contractors should be used if necessary. Tennessee requires accreditation for asbestos work in schools and commercial buildings.

Asbestos in Schools
Older schools may contain asbestos. Since 1986, the Asbestos Hazard Emergency Response Act (AHERA) has required inspections and management plans. Parents with concerns should contact their local school board.

EPA Guidance on Asbestos

Asbestos is hazardous, but risk depends on exposure.
Levels in most buildings, including schools, are generally low.
Improper removal can increase danger.
Removal is only required to prevent major exposure, such as during renovation.
EPA recommends in-place management when materials are intact and unlikely to be disturbed.

Importance of Children’s Environmental Health

Children are more vulnerable than adults because they breathe, eat, and drink more relative to their body weight and have little control over their environments. They are also less aware of risks and cannot make choices to protect themselves. Promoting safe environments helps Tennessee children live, learn, grow, and play in healthier settings.

Quick Tips for Protecting Children’s Health

Avoid smoking or drinking during pregnancy and around children.
Teach proper hygiene, especially handwashing.
Use safe, high-quality nutrition, including infant formula when needed.
Check older homes (built before 1978) for lead paint.
Limit pesticide use indoors and outdoors.
Garden in clean soil to avoid contamination.
Clean and vacuum with non-toxic products.
Test private well water for safety.
Choose toys and furniture free of harmful chemicals (phthalates, BPA, flame retardants).
Install carbon monoxide detectors.
Replace HEPA filters yearly.
Encourage regular physical activity.

Places Children May Encounter Hazards
Children can be exposed at home, school, child care centers, or playgrounds—virtually anywhere in their daily lives.

Common Routes of Exposure
Children come into contact with environmental hazards through:

Placental transfer before birth
Skin contact
Inhalation
Ingestion

Risks by Developmental Stage
Children’s susceptibility varies with growth and development.

Prenatal Stage (conception to birth):

Embryonic stage (8 days–9 weeks): Organs and systems form; exposures during this period can cause defects and delays, often before pregnancy is recognized.
Fetal stage (9 weeks–birth): Organs mature and grow. While the placenta offers some protection, pollutants like radiation, lead, or mercury can still cause harm, including intellectual disability, low birth weight, or premature birth.

Infants and Toddlers (Birth–3 Years)

Children in this stage face higher risks due to rapid growth, immature physiology, and exploratory behaviors.
Increased intake: Infants eat and drink more per pound of body weight, which can lead to greater exposure to contaminants in food, water, and air. Chemicals like BPA can leach from plastics into food and drinks.
Higher breathing rates: Infants breathe about three times faster than adults, making them more vulnerable to air pollution.
Greater skin absorption: Thinner, more permeable skin allows faster absorption of harmful substances from personal care products, pesticides, and cleaning agents.
Hand-to-mouth behavior: Crawling and mouthing objects increases ingestion of dust, dirt, and toxins such as lead, pesticides, and plasticizers.

Preschoolers (3–5 Years)

With increased mobility and independence, preschoolers are exposed to more environmental risks.
More time outdoors: Outdoor play supports development but also increases exposure to air pollution, pesticides, contaminated water, and climate hazards.
Time indoors: Long indoor periods for rest or play may expose children to pollutants from mold, dust, plastics, and volatile organic compounds.
Behavioral patterns: Playing close to the ground and frequent hand-to-mouth activity increase ingestion of toxic substances and germs.

School-Aged Children (6–12 Years)

School environments bring unique exposures during a critical stage of growth and learning.
Indoor air quality: Poor ventilation in classrooms, gyms, or bathrooms can lead to exposure to dust, mold, pollen, lead, or fiberglass, affecting respiratory health.
Outdoor air quality: Playgrounds and sports fields may be affected by traffic emissions, nearby industries, pesticide use, or local geography.
Water quality: Lead contamination remains a concern in schools with old plumbing. Other risks include flame-retardant chemicals, hydrocarbons, or bacteria—especially in private well systems.
Social and behavioral factors: Peer interactions may introduce risks such as secondhand smoke or early exposure to alcohol and other harmful substances.

Defining Chlorine
Chlorine is a greenish-yellow, poisonous gas with a sharp odor. It is highly corrosive and hazardous. While not flammable, it can react explosively with common household products like vinegar or ammonia.

Using Chlorine
Chlorine is one of the most widely manufactured U.S. chemicals. It is used in:

Household bleach and pool shock
Drinking water disinfection
Wastewater and sewage treatment
Pesticides, synthetic rubbers, and refrigerants
Paper and cloth production

Exposure to Chlorine
People may be exposed to chlorine through:

Inhalation: accidental gas release, mixing bleach with ammonia, or mishandling pool chemicals
Skin/eye contact: direct exposure to chlorine gas or liquid
Ingestion: contaminated water or food

Health Effects of Chlorine
Chlorine is safe when properly used but harmful in excess. Effects depend on dose, route, and duration of exposure.

Immediate symptoms may include:

Burning eyes, nose, throat, or skin
Coughing, wheezing, chest pain, or shortness of breath
Blurred vision, watery eyes, dizziness, nausea, or headache
Blisters, frostbite, or fluid in the lungs (at high doses)

Children are more vulnerable due to their smaller airways, higher breathing rates, and shorter height (closer to ground-level gas concentrations).

Chronic exposure risks: tooth corrosion, lung disease (bronchitis, shortness of breath), or reactive airways dysfunction syndrome. Severe or high-level exposure can be fatal.

Responding to Chlorine Exposure

Move immediately to fresh air.
Remove clothing and wash skin with soap and water.
Flush eyes with plain water if irritated.
Do not induce vomiting or drink fluids if ingested.
Seek medical help immediately; call 911 or the Tennessee Poison Center (1-800-222-1222).

Preventing Chlorine Exposure

Never mix bleach with ammonia or other cleaners.
Store chemicals in original labeled containers, out of children’s reach.
Avoid reusing food or drink containers for chemical storage.
Handle pool chemicals carefully.
Follow product labels and keep chlorinated products away from children.

Understanding Climate Change and Health

Human activity releases pollutants, including greenhouse gases, that trap heat in the atmosphere. This has led to global warming and climate change, with impacts such as rising temperatures, shifting precipitation, stronger storms, sea-level rise, and more frequent extreme weather events. These changes threaten public health by increasing illness, death, and displacement.

Recognizing Health Impacts of Climate Change

Extreme weather: Stronger storms and more flooding increase injury, displacement, and stress.
Heat: Rising temperatures cause heat-related illness and lengthen allergy seasons.
Air quality: Higher pollution and wildfire smoke worsen respiratory disease.
Water and food: Droughts and rainfall changes disrupt food and water supplies.
Infectious disease: Warmer conditions expand the range of disease-carrying organisms.
Mental health: Stress, anxiety, and trauma may rise after disasters.
Civil conflict: Scarcity of food, clean water, and shelter may spark social unrest.

Identifying Vulnerable Populations
Health impacts are not equal. Children, older adults, and people with limited access to health care or financial resources face the greatest risks. Extreme events also strain health systems and emergency services.

Promoting Climate Resilience and Adaptation
Adaptation strategies help communities prepare and recover, such as:

Planting drought-resistant crops
Building infrastructure above flood levels
Reducing stormwater risks in cities with more green space
Planning for urban heat islands and improving air quality

Resilient communities safeguard infrastructure, conserve resources, maintain property values, and recover more quickly from disasters. 

Strengthening the Public Health Response
An effective response to climate change prevents injury, illness, and death while improving preparedness. The CDC’s Building Resilience Against Climate Effects (BRACE) framework guides health officials through five steps:

1. Anticipate climate impacts and assess vulnerabilities
2. Project disease burden
3. Evaluate public health interventions
4. Develop and implement an adaptation plan
5. Measure results and improve strategies

Advancing Environmental and Health Goals
Protecting the environment supports public health: what benefits ecosystems usually benefits people. Federal, state, and local partnerships—including Tennessee Department of Health leadership—highlight the urgent need to reduce greenhouse gases, adapt to changing conditions, and protect communities.

Defining Ethylene Oxide
Ethylene oxide (EtO) is a manmade, colorless gas used mainly to:

Make chemicals for fabrics, plastics, antifreeze, detergents, glues, and cosmetics
Sterilize medical equipment that cannot be steam-cleaned
Disinfect some food products such as spices, dried herbs, sesame seeds, and walnuts

Regulating Ethylene Oxide
EtO emissions are regulated by the U.S. Environmental Protection Agency (EPA) under the Clean Air Act. In March 2024, EPA finalized stricter rules for commercial sterilizers, requiring a 90% reduction in emissions. Facilities have 2–3 years to comply, depending on how much EtO they use. Once implemented, no community should face a lifetime cancer risk above 100 in 1 million from EtO exposure.

Understanding Exposure to Ethylene Oxide

Community exposure: People living near facilities may be exposed to fugitive emissions (small amounts escaping pollution controls). EPA’s 2024 rule will significantly reduce this risk.
Workplace exposure: Workers in chemical plants, sterilization facilities, or hospitals may experience higher-than-average exposure.

Recognizing Health Effects of Ethylene Oxide

Short-term high exposure: Dizziness, nausea, headache, fatigue, respiratory irritation, and sometimes vomiting or stomach distress.
Long-term exposure: Increased cancer risk, particularly for certain blood cancers and breast cancer, as shown in worker and animal studies.
Community risk: Greatest for people living near emitting facilities for their entire lifetime.
EPA does not expect outdoor air levels near facilities to cause sudden or acute effects.

Testing for Ethylene Oxide Exposure
ATSDR notes two short-term tests can detect recent exposure:

Blood test measuring EtO levels
Breath test detecting EtO in exhaled air

These tests:

Only work for recent exposure (EtO leaves the body within hours or days)
Do not predict health outcomes
Are not useful for detecting past low-level exposure
Are not usually available in a doctor’s office

Facts About Lead

Exposure can harm babies before birth
Healthy-looking children may still have high lead levels
Peeling or chipping lead paint is a hazard
Young children are at greater risk due to hand-to-mouth behavior
Lead-based paint in good condition is usually not a hazard
Lead can be carried home from jobs on clothing and shoes
Before 1978, lead was added to gasoline and house paint
Some imported toys, jewelry, foods, or medicines may contain lead

What Lead Is and Why It Matters
Lead is a naturally occurring metal once widely used in paint, plumbing, gasoline, and consumer products. It is toxic and can cause serious, sometimes permanent, health effects—especially in children under age six. Although banned from house paint in 1978, many older homes and buildings still contain lead hazards.

Common Sources of Lead Exposure

Deteriorating lead-based paint in homes built before 1978
Dust or soil contaminated with lead
Old plumbing fixtures with lead pipes or solder
Imported toys, jewelry, foods, or folk remedies
Certain hobbies (e.g., stained glass, pottery, refinishing furniture)

How Lead Enters the Body

Ingesting lead dust, soil, or paint chips
Breathing in lead dust
Drinking water from old lead pipes
Eating or handling products containing lead
Bringing lead home from workplaces

Health Effects of Lead

In children:
Brain and nervous system damage
Learning and behavior problems
Slowed growth and poor coordination
Hearing problems, headaches

In adults:
Reproductive problems
High blood pressure
Nerve and digestive disorders
Memory and concentration issues
Muscle and joint pain

Children absorb lead more easily than adults, and brain damage from lead exposure is often permanent.

Where Lead May Be Found at Home

Peeling or chipping paint on windows, doors, porches, railings, and fences
Lead dust from sanding, scraping, or friction between painted surfaces
Old plumbing and solder, which may release lead into water
Old or imported toys, furniture, blinds, jewelry, pottery, or candy wrappers

Protecting Your Family

Clean up paint chips immediately
Wet-mop floors and clean window sills weekly
Wash children’s hands, bottles, and toys often
Provide healthy meals—nutritious diets help reduce lead absorption
If you work with lead, shower and change clothes before going home
Hire only certified lead abatement professionals for cleanup or renovation

Lead Testing and Regulations

Children under six should receive periodic blood lead tests
A safe level is below 5 micrograms per deciliter (µg/dL)
Federal law requires landlords and sellers of pre-1978 homes to disclose known lead hazards
Since 2010, contractors disturbing lead-based paint in pre-1978 housing or child facilities must be EPA-certified and use lead-safe work practices

Introduction to Mercury
Mercury is a naturally occurring metal that exists in three main forms:

Metallic (elemental) mercury – silver-colored liquid at room temperature, used in thermometers and some light bulbs. It easily evaporates, and breathing vapors can be harmful. 
Inorganic mercury – compounds formed when mercury combines with chlorine, sulfur, or oxygen; often white powders or crystals. Toxic if swallowed.
Organic mercury – formed when mercury combines with carbon. The most common type, methylmercury, builds up in fish and wildlife and can be harmful if eaten in large amounts.

Mercury in Thermometers

Older household thermometers may contain mercury.
A small spill (e.g., from a broken thermometer) is a nuisance but not an emergency.
Cleanup tips: never use a vacuum, ventilate the area, and collect beads with cardboard, tape, or an eyedropper.
Mercury thermometers are no longer recommended—digital or mercury-free options are safer.

Proper Disposal of Mercury Items

Bring mercury thermometers and other devices (thermostats, barometers, pressure cuffs, etc.) to a Household Hazardous Waste Collection site.
Permanent collection sites exist in Davidson, Hamilton, Knox, and Shelby counties.
Other counties hold special collection days.
For details, call 615-532-9265.

Mercury in Light Bulbs

Fluorescent tubes, metal halide, mercury vapor, and compact fluorescent light bulbs (CFLs) contain small amounts of mercury.
CFLs are energy-efficient and reduce overall mercury emissions by lowering fossil fuel use.
Always dispose of these bulbs responsibly.

Chemistry and Environmental Cycling

Metallic mercury – liquid metal that can evaporate.
Inorganic mercury (salts) – may cause poisoning if ingested.
Organic mercury (methylmercury) – bioaccumulates in fish and wildlife, harmful to people who eat contaminated fish.

Mercury cycles naturally and through human activity. Burning fossil fuels, waste incineration, and improper disposal release mercury into the environment. Natural processes can convert mercury into methylmercury, which enters the food chain through fish and wildlife.

Understanding Mold

Molds are fungi that grow both indoors and outdoors.
Thousands of mold types exist in Tennessee and worldwide; many produce spores that spread through the air and grow on surfaces when moisture is present.
Moisture is required for mold growth—any indoor mold indicates a water problem.
Common indoor molds: Cladosporium, Penicillium, Alternaria, Aspergillus, Trichoderma.
Large infestations are often visible or produce a musty odor.

Health Effects of Mold

Mold exposure is usually not harmful unless it multiplies in damp areas.
Molds can produce allergens, irritants, and sometimes mycotoxins.
Most people have no reaction; sensitive individuals may experience:

Allergic reactions
Irritation of eyes, skin, nose, or throat
Asthma attacks in people with asthma

No proven link exists between mold and memory loss, lethargy, or infant pulmonary hemorrhage.
“Toxic mold” is a misleading term—mold itself is not poisonous.

Testing for Mold
Testing is usually unnecessary. Both CDC and EPA recommend cleaning mold and addressing moisture regardless of mold type. Presence of mold does not automatically mean a health risk.

Preventing Mold Growth
Key principle: control moisture.

Prevention tips:

Fix leaks in pipes, roofs, and windows
Maintain indoor humidity at 30–50%
Inspect and maintain HVAC systems regularly
Avoid carpeting in bathrooms and basements
Ventilate showers, laundry, and cooking areas
Clean and dry the home promptly after flooding

Cleaning Up Mold
Personal protection: gloves, mask, and goggles. Avoid direct contact and inhalation.

Methods:

Dry wet, non-moldy materials within 48 hours
Clean mold from hard surfaces with water and detergent; dry quickly
Bleach solution (1 cup bleach per gallon of water) can be used; never mix with ammonia
Discard porous items that cannot be cleaned (carpets, upholstery)
Do not paint or caulk over mold—must remove physically

Mold in Schools and Workplaces

Consult a healthcare provider if you or your child show symptoms related to mold exposure.
Notify building maintenance to clean mold and fix moisture issues.

Understanding Ozone
Ozone is a gas found both high in the atmosphere and at ground level, with different impacts depending on its location. Good ozone: Found in the stratosphere (6–30 miles above Earth). Protects life from harmful UV rays. Bad ozone: Found in the troposphere (ground level to ~6 miles). A harmful air pollutant that damages lungs, vegetation, and contributes to smog.

Good Ozone (Stratospheric)

Naturally formed when UV rays react with oxygen.

Depleted by human-made chemicals called ozone-depleting substances (ODS), including CFCs, HCFCs, halons, and methyl bromide.

Health impacts of depletion: Increased UV exposure can lead to:

Skin cancer, cataracts, and immune system suppression
Damage to crops and marine phytoplankton, affecting food supply

Actions taken:

Montreal Protocol (1987) phased out ODS internationally.
EPA regulations prohibit nonessential uses of ODS and require safe handling of refrigerants.
Recovery of the ozone layer is expected by 2050 if ODS emissions remain controlled.

Personal protection from UV:

Limit outdoor activities when UV Index is high (10 a.m.–4 p.m.)
Apply broad-spectrum sunscreen (SPF 15+) 20 minutes before exposure; reapply every 2 hours or after swimming/sweating
Use certified refrigerants and repair leaky air conditioners

Bad Ozone (Ground Level)
Formed when nitrogen oxides (NOx) and volatile organic compounds (VOC) react in sunlight. Major sources: vehicle exhaust, industrial emissions, power plants, gasoline vapors, chemical solvents. Peaks in hot, sunny weather, especially during summer.

Health effects:

Respiratory irritation: chest pain, coughing, throat irritation
Worsened asthma, bronchitis, and emphysema
Reduced lung function; repeated exposure may scar lungs
Children, outdoor workers, and people with chronic conditions are most vulnerable

Environmental impacts:

Damages crops and forests
Reduces tree growth and survivability
Causes millions in agricultural losses annually

Actions to reduce ground-level ozone:

Check Air Quality Index (AQI) and limit strenuous outdoor activity when ozone levels are high (www.airnow.gov)
Reduce emissions:

Conserve energy at home and office
Properly maintain vehicles and gasoline-powered equipment
Carpool, walk, bike, or use public transport

Use low-VOC paints and solvents

Understanding PFAS
Per- and polyfluoroalkyl substances (PFAS) are a large group of man-made chemicals not naturally found in the environment. Over 3,000 PFAS chemicals exist. Two well-known PFAS are:

PFOA – perfluorooctanoic acid

PFOS – perfluorooctane sulfonic acid

Where PFAS Are Found
PFAS have been used since the 1950s in:

Stain-resistant carpets and fabrics
Water-repellent clothing
Non-stick cookware
Food packaging
Firefighting foam
Other grease, water, and oil-resistant products

PFAS are persistent in the environment and can be found in:

Air, soil, and water near manufacturing sites or areas where firefighting foam was used
Indoor dust and certain consumer products

How People May Be Exposed
The main routes of exposure are:

Drinking water or consuming food contaminated with PFAS
Using products containing PFAS
Breathing in PFAS from air or indoor dust

Potential Health Effects
Research on PFAS is ongoing. Evidence suggests certain PFAS may:

Increase cholesterol
Reduce vaccine response
Affect thyroid function
Decrease fertility in women
Increase risk of high blood pressure or pre-eclampsia during pregnancy
Slightly lower infant birth weight

Animal studies also show potential for:

Liver and immune system damage
Birth defects, delayed development, and newborn deaths
Certain cancers (liver, testes, pancreas, thyroid)

Human studies indicate possible links to kidney and testicular cancer. PFOA is classified as possibly carcinogenic to humans by the International Agency for Research on Cancer.

Testing for PFAS
A blood test can measure PFAS levels but is not routine in medical offices. A positive test shows exposure but cannot predict health effects or when exposure occurred.

Health Recommendations

EPA drinking water guideline: 70 parts per trillion for PFOA and PFOS in municipal water
ATSDR Minimum Risk Levels (MRLs) estimate safe daily intake:

PFOA: 0.000003 mg/kg/day
PFOS: 0.000002 mg/kg/day

Private well owners are responsible for testing and ensuring water safety

Understanding Pesticides
Pesticides are substances used to control pests—organisms that can harm people, animals, or plants. They include:

Insecticides – for insects
Herbicides – for plants
Fungicides – for fungi
Rodenticides – for rodents

Pests can be insects (cockroaches, mosquitoes), rodents (mice, rats), weeds (dandelions, poison ivy), or fungi (mold).

Benefits of Pesticides
Properly used, pesticides help to:

Reduce disease-carrying insects (mosquitoes, ticks)
Protect crops and gardens
Control insects and rodents in homes
Eliminate harmful bacteria, fungi, or algae

Risks of Pesticides
Misuse or overuse can harm people, pets, wildlife, and the environment. Many pesticides are poisonous if ingested and can irritate skin or eyes. Always follow label directions for safe use, storage, and disposal.

Common household products containing pesticides:

Bug sprays and baits
Flea and tick products
Lawn and garden insect killers
Mold/mildew cleaners
Pet collars
Mosquito repellents
Rat and ant poisons

Symptoms of Pesticide Poisoning
Symptoms vary by chemical and exposure but may include:

Skin, eye, nose, or throat irritation
Shortness of breath or rapid breathing
Nausea, vomiting, abdominal cramps, diarrhea
Fatigue, headache, sleepiness
Muscle twitching, numbness

Reducing Risk of Pesticide Exposure

Read and follow label directions
Use only the recommended amount; more is not better
Use indoor-approved pesticides inside
Wear gloves, masks, and goggles
Keep children and pets away from treated areas
Store pesticides in locked cabinets
Dispose of pesticides properly
Use safe pesticides for food crops
Minimize pesticide use with Integrated Pest Management (IPM)
Use less-toxic alternatives like boric acid powder or natural pyrethrum
Sensitive groups (children, pregnant women, elderly, ill individuals) may be more vulnerable.

Regulations and Safety
Tennessee Department of Agriculture (TDA) regulates pesticide use, registers pesticides, and investigates misuse. 

Proper disposal: Never pour pesticides down sinks, drains, or on the ground. Use TDEC’s household hazardous waste collection programs.

Natural Alternatives to Pesticides

Cedar wood (naturally insect-resistant)
Pyrethrum (from chrysanthemum flowers)
Boric acid powder for cracks and crevices
Integrated Pest Management (IPM) – a safer, effective approach using multiple control strategies

If Pesticide Poisoning is Suspected

Life-threatening symptoms: Call 911 immediately (unconscious, breathing problems, convulsions)
Non-emergency exposure: Call Tennessee Poison Center at 1-800-222-1222
Also: National Pesticide Information Center at 1-800-858-7378

What is a Private Water Supply?
About 10% of Tennesseans use private water supplies, typically wells or springs, for household water. These supplies are generally unregulated—well construction is regulated, but water quality is not. Nationally, about 42 million Americans rely on private wells or other small systems. Common well types: drilled, dug, or driven.

Health Concerns
Private water often goes untested and may contain:

Chemicals: petroleum, solvents, metals
Biological contaminants: bacteria, parasites, viruses
Radon (in homes with high indoor radon)

Wells in karst areas (limestone, caves, fissures) are more vulnerable to contamination because water flows quickly, carrying pollutants long distances.

Testing Recommendations

Bacteria: annually (multiple samples)
Chemicals (nitrates, metals): every 2 years
Volatile organic compounds: every few years (if near industry)
Radon: if your home has elevated indoor radon

Always review results with TDEC’s Division of Water Resources (1-888-891-TDEC) or EPA’s Safe Drinking Water Hotline (1-800-426-4791). A water treatment system may be needed depending on test results.

Planning a New Well
Well location must be a safe distance from contamination sources:

Other precautions:

Place wells away from underground storage tanks, fertilizers, and pesticides (EPA recommends 100 ft).
Seal well casing to prevent surface water seepage.
Build above flood levels, away from rooftops, power lines, or future construction sites.
Slope ground away from the well.

Disinfecting a New or Serviced Well

Add 1 gallon chlorine bleach per 50 ft of well depth.
Run faucets until chlorine odor is noticed, then let sit 12 hours.
Flush water until odor is gone (do not discharge to septic systems, streams, or lakes).
Repeat after any servicing of the well, pump, or pipes.

Protecting Groundwater Quality

Inspect wells regularly for cracks, corrosion, or broken caps.
Cap and seal wells securely.
Test annually for bacteria and nitrates.
Keep maintenance records.
Hire certified drillers for new wells, modifications, or closures.
Keep chemicals, fertilizers, fuels, and waste away from wells.
Do not dispose of waste or hazardous materials in wells or septic systems.

More Information

TDEC Division of Water Resources: 1-888-891-TDEC (8332)
Private Well Owner Hotline: 1-855-420-9355
EPA Safe Drinking Water Hotline: 1-800-426-4791

What is Sodium Hydroxide (NaOH)?

Also called caustic soda or lye
Common in cleaners, soaps, and drain openers
At room temperature: white, odorless solid (pellets, flakes, granules)
In solution: colorless, odorless liquid
Corrosive—reacts with acids, water, and air moisture, releasing heat that can ignite flammable materials

Common Uses

Household: soaps, detergents, drain cleaners, oven cleaners
Industry (about 56% of use):

Paper and paper recycling (25%)
Food processing (peeling vegetables, curing foods)
Aluminum refining and metal treatment
Cotton processing, textiles
Bleach and water treatment
Pharmaceuticals (pain relievers, anticoagulants, cholesterol drugs)
Fuel cell production

Exposure Pathways

Home: accidental skin/eye contact or ingestion of cleaners/soaps
Workplace: inhalation or contact in facilities that use NaOH
Air exposure limits (all set at 2 mg/m³, not to be exceeded):

OSHA PEL (legal limit)
NIOSH REL (recommended)
ACGIH TLV (threshold value)

Protecting Your Family

Read and follow label directions
Store securely—keep out of reach of children, in original containers
Use gloves (latex or nitrile), long sleeves, and protective clothing when handling strong solutions
Remove contaminated clothing carefully to avoid skin spread

Health Hazards

Skin/eye contact: severe burns, permanent damage
Ingestion: immediate burns, vomiting, chest/stomach pain, swallowing difficulty, possible death
Inhalation: irritation, coughing, respiratory burns, potential long-term lung damage
Chronic exposure: dermatitis, repeated lung irritation

Severity depends on concentration, duration, and route of exposure.

First Aid

Call 911 in emergencies
Eyes: flush with water 30 min, remove lenses
Skin: remove clothing, rinse with water 15 min
Inhalation: move to fresh air; begin CPR if unresponsive
Ingestion: do NOT induce vomiting; give water if fully conscious; call Poison Center 1-800-222-1222

Spills and Storage

Spills:
Evacuate area, eliminate ignition sources
Absorb liquids with dry earth/sand; collect solids safely
Use sealed containers for disposal (hazardous waste rules may apply)
DO NOT use water or flush to sewer

Reactivity:
Violently reacts with acids, water, and moisture
Reacts with metals (aluminum, zinc, lead, tin) to release hydrogen gas (flammable, explosive)
Incompatible with oxidizers, chlorinated solvents, ammonia, and organic materials

Storage:
Keep in original, tightly sealed containers
Store in cool, dry, ventilated areas, away from moisture and incompatible substances
Can damage iron, copper, plastics, rubber, and coatings

What is Vapor Intrusion?
Vapor intrusion occurs when volatile chemicals from contaminated soil or groundwater migrate into indoor air. These chemicals may come from spills, dumping, disposal practices, or nearby industrial releases. Vapors can enter buildings much like radon gas.

How Do Vapors Enter Buildings?
Chemical vapors move from areas of higher concentration to lower concentration (diffusion). They may enter through:

Cracks in floors and foundations
Utility openings or crawl spaces
Pressure changes, wind, or building exhaust fans

Movement depends on soil type, chemical properties, and building design.

Common Chemicals at Vapor Intrusion Sites

Gasoline components: benzene, toluene, ethylbenzene, xylenes
Solvents: tetrachloroethylene (PCE), trichloroethylene (TCE)
Others: dieldrin, mercury, hydrogen sulfide, methane

The most common are benzene, PCE, TCE, and methane.

Who is at Risk?
Anyone living, working, or spending time in buildings above contaminated soil or groundwater may be exposed. Infants, unborn babies, the elderly, and people with chronic illnesses are more vulnerable.

How Are People Exposed?
Vapors migrate indoors through cracks, pipes, or crawl spaces. Roofs and walls can trap these vapors, allowing them to build up indoors over time.

Can Vapor Intrusion Be Harmful?
Yes. Testing has shown it can pose health risks. In many cases, levels are low and risks are considered theoretical—based on continuous lifetime exposure (24 hours/day for 70 years). Some states require cleanup even when indoor levels are far lower than workplace safety limits set by OSHA.

How Do You Know If It’s Happening?
The only way to confirm vapor intrusion is testing indoor air. Soil vapor or soil-gas tests under or near a building may also be done.

What Should You Do if You Suspect Vapor Intrusion?
Check whether chemical spills or industrial activities occurred near your home, workplace, daycare, or school. If no such activities occurred, the risk is low. Currently, no household monitors (like smoke alarms) can detect vapor intrusion—professional testing is required.

Helpful Links  for Environmental Epidemiology Topics

The following links are to websites of other State of Tennessee Departments or webpages with the Tennessee Department of Health.

The following links are to external, third-party websites. The Tennessee Department of Health is not responsible for their accessibility, content, or information. 

Investigating Unusual Patterns of Cancer and Environmental Concerns

Cancer and the Environment
Cancer is common—about 1 in 2 men and 1 in 3 women in the U.S. will be diagnosed in their lifetime. When people notice clustering of cancer cases in their community, they often wonder if environmental exposures might be to blame. The Tennessee Department of Health (TDH) investigates such concerns in collaboration with partner agencies. 

What is a Cancer Cluster or Unusual Pattern?
A cancer cluster is when more people than expected develop the same or etiologically related cancers in a defined area and timeframe.  An unusual pattern is similar but lacks a clear geographic boundary (e.g. cases among users of the same water system). Because cancer is common and has many causes, observed clusters often result from chance. 

How TDH Responds to Concerns
When someone reports a possible cluster, TDH collects details such as:

Location (city, ZIP code, neighborhood)
Type(s) of cancer
Number of cases
Timeframe
Patient ages, diagnosis dates
Possible exposures or health risk factors

TDH then determines whether a formal cancer investigation is warranted, using data from the Tennessee Cancer Registry and environmental agencies. 

Possible outcomes include:

No unusual clustering found
Clustering found, but no clear cause
Clustering found, and a cause may be identified

TDH shares results publicly and may suggest further investigation if needed. 

Why a Link to Environment Is Unlikely
Cancer has multiple and overlapping causes (genetics, behavior, environment). Environmental exposures often take years to manifest. Population movement complicates exposure tracking. Not everyone exposed to a carcinogen develops cancer.

Limitations & Challenges
Small case numbers can lead to unstable statistics. Defining geography and time periods introduces uncertainty. These studies are ecological—meaning they assess groups, not individuals—and cannot prove causation.

Resources
Tennessee Cancer Registry
Tennessee Comprehensive Cancer Control Program
Tennesee Department of Health Data
https://healthdata.tn.gov/

CDC's Unusual Patterns of Cancer, the Environment, and Community Concerns
www.cdc.gov/cancer-environment/about/index.html

National Cancer Institute
www.cancer.gov/about-cancer/causes-prevention

American Cancer Society
www.cancer.org/cancer/risk-prevention/understanding-cancer-risk/cancer-clusters.html

Understanding Chemical Exposure

Exposure occurs when a chemical enters the body through breathing, touching, eating, or drinking. Exposures can happen quickly or build up over time.

Sources of Exposure
Chemicals come from sources such as spills, dumps, landfills, ponds, tanks, smokestacks, car exhaust, cigarette smoke, or cleaning products. They can travel through air, water, soil, plants, or animals. Eating contaminated food, such as fish from a polluted pond, is another route of exposure.

Factors That Influence Illness
Not all exposures cause illness. Risk depends on:

Type and toxicity of the chemical

Amount, duration, and frequency of exposure

Individual sensitivity (children, for example, are often more vulnerable)

Some effects appear quickly, while others develop after long-term, repeated contact. Symptoms like nausea or headache often stop when exposure ends. If you are not exposed, you cannot get sick.

Pathways Into the Body
Chemicals can enter the body through:

Inhalation – breathing in dusts, mists, or gases that may harm lungs or enter the bloodstream

Ingestion – eating or drinking contaminated food, water, soil, or dust

Contact – skin absorption from touching chemicals or contaminated surfaces

Reducing or Preventing Exposure
Steps to reduce or prevent exposure include:

Using water filters or bottled water if water is contaminated

Washing hands, clothes, and shoes after contact with contaminated soil

Limiting dust and avoiding hand-to-mouth contact near polluted areas

Using air purifiers or filters when chemicals are present in the air

The Department of Health provides site-specific guidance to help reduce or eliminate exposure.

Defning Exposure Investigations

An exposure investigation helps the Environmental Epidemiology Program understand past, current, and future human exposure to hazardous substances. Information is gathered through:

Biomedical tests – blood or urine testing to detect current or past exposure
Environmental samples – soil, water, or air testing from places where people live, work, or play
Exposure-dose reconstruction – computer models using sampling data to estimate past or future exposure and possible health effects

Conducting Investigations
A multidisciplinary team may include experts in sampling, toxicology, risk analysis, epidemiology, GIS, medicine, and community engagement. They analyze findings, prepare reports, involve the community, and recommend health protections.

Involving the Community
Community participation is essential. Successful investigations require:

Local interest and input
Consent for testing
Clear understanding of what results can and cannot show

Investigations identify exposure but do not measure actual harm.

Deciding to Investigate
An investigation is considered when:

People are likely exposed or at risk
More information is needed about exposure routes
Findings would add useful knowledge
Results would guide public health decisions

Reasons Not to Investigate
An investigation may not be done if:

No exposure pathway exists
Exposure happened too long ago for detection

In such cases, other methods may be used to address community health concerns.

What is a health consultation?

A health consultation is a report that provides advice on a public health issue related to human exposure to a hazardous substance. A health consultation is a response to an environmental public health question. It is not the same as a medical exam, community health study or public health assessment. A health consultation is a way for the Tennessee Department of Health Environmental Epidemiology Program, to respond to a need for health information about a hazardous substance and to make recommendations to protect the public’s health.

Click here for a printable version of this fact sheet.

A health consultation considers:

how much (the concentration) of a hazardous substance is present at a site;
whether people have been or might become exposed the hazardous substance;
what exposure pathways such as breathing, touching, eating, or drinking, are present at the site or in the community;
what harm (the toxicity) a hazardous substance might cause to people;
whether living or working near a hazardous waste site might affect people’s health; and
other dangers to people, such as unsafe buildings, dangerous objects, abandoned mine shafts or other physical hazards.

A health consultation often includes:

background
statement of Issues
discussion
child Health Considerations
conclusions
recommendations
public health action plan
references
tables and figures
maps and photos
certification

Health consultations for download:

See the next dropdown menu for information on Public Health Assessments.

What is a public health assessment?

A public health assessment reviews available information about hazardous substances at a site. It evaluates whether exposure to chemicals might harm people. A public health assessment considers all environmental issues related to actual or possible human exposure. A Public Health Assessment is not the same thing as a medical exam or a community health study. A public heath assessment can be prepared by either the Tennessee Department of Health, Environmental Epidemiology Program, or the federal Agency for Toxic Substances and Disease Registry (ATSDR).

A public health assessment uses three primary sources of information:

environmental data, such as measurements of chemicals and the pathways that people could come into contact with them;
health data, including available information on community-wide rates of illness, injury, disease, or death compared with national and state rates; and
community concerns, such as information from the general public about how the site may have affected their health or quality of life

A Health Assessment often includes:

background
statement of Issues
discussion
child health considerations
conclusions
recommendations
public health action plan
references
tables and figures
maps and photos
certification

A public health assessment considers:

how much (the concentration) of a hazardous substance is present at a site;
whether people have been or might become exposed to the hazardous substance;
what exposure pathways,such as breathing, touching, eating, or drinking, are present at the site or in the community;
what harm (the toxicity) a hazardous substance might cause to people;
whether living or working near a hazardous waste site might affect people’s health; and
other dangers to people, such as unsafe buildings, dangerous objects, abandoned mine shafts, or other physical hazards.

Chattanooga SoilSHOP

What was the situation?
The federal Soil Screening, Health, Outreach and Partnership (SoilSHOP) program helps communities test soil for safety and gardening. SoilSHOPs are especially useful near industrial sites, spill areas, and community gardens.

What was done to assist the community?
TDH, along with CDC, EPA, TDEC and others, held Tennessee’s first SoilSHOP in Chattanooga during Lead Poisoning Prevention Month. Residents brought yard soil to be tested for lead and other metals. Most results were acceptable; families with high levels received additional health education. Planning for future events is underway.

Wrigley Charcoal Public Availability Session

What was the situation?
From the 1880s–1996, Wrigley Charcoal in Hickman County manufactured charcoal and by-products, leaving hazardous waste that placed the site on the EPA’s National Priorities List. Later, a plastics recycling facility operated there until a 2013 fire forced nearby evacuations.

What was done to assist the community?
EPA hosted a public availability session to explain cleanup efforts. TDH and TDEC staffed booths, addressing community concerns about the fire, cancer rates, air quality, site reuse, and waste management. A follow-up FAQ letter was shared with attendees.

Protecting Children from Vapor Intrusion inside a Daycare

What was the situation?
In 2011, TDEC asked TDH to evaluate vapor intrusion risks from a groundwater plume of tetrachloroethylene near a daycare. Children could be at risk if vapors migrated indoors.

What actions were taken?
TDH and TDEC reviewed data gaps, conducted a soil-gas investigation, and tested indoor air at the daycare. Results showed groundwater contamination moving away from the daycare, but testing confirmed indoor air was unaffected.

What was the public health impact?
Chemical levels inside the daycare were not harmful. Children and staff were not at risk.

Sampling Indoor Air in Homes Near a Lacquer Manufacturer

What was the situation?
In 2009, TDEC asked TDH to sample indoor air in homes near a lacquer plant where groundwater was contaminated with acetone, toluene, and benzene. The concern was vapor intrusion into homes.

What actions were taken?
TDH collected 24-hour indoor and outdoor air samples at three homes. Results were compared to EPA and ATSDR screening values.

How did this affect public health?
Two homes had chemical levels similar to outdoor air and below harmful levels. One home showed elevated benzene, likely from gasoline and equipment stored in the basement.

TDH Assists after the TVA Coal Ash Release

What was the situation?
On December 22, 2008, a TVA coal ash pond failed in Kingston, TN, causing one of the nation’s largest environmental disasters. TDH worked with EPA and other agencies to assess public health impacts.

What actions were taken?
TDH gathered and analyzed environmental data across all media, issued a Public Health Assessment (2010), conducted an EpiAid with CDC, visited 324 homes, and provided education to health care providers.

What was the public health impact?
Health assessments and screenings by Oak Ridge Associated Universities and Vanderbilt University Medical Center found no unexpected adverse effects. Results were shared publicly in 2010. Dr. John Benitez of Vanderbilt received the Society of Toxicology’s 2012 Translational Impact Award for this work.