Pathways into the body – Environmental Hypersensitivity

Exposure to initiating and triggering agents can take place via the respiratory system, the digestive system, skin contact, contact with infectious agents, injection of products and medical interventions. Exposure can happen as early as mother to child transmission during pregnancy and breastfeeding.

The body reacts differently depending on the type of exposure and whether it is a chemical, physical or biological contaminant.

Table 1 Agents likely to bring about the onset of environmental sensitivities.

**Table 1** Agents likely to bring about the onset of environmental sensitivities.
Type of agent	Examples of agents	Examples of sources or products
Volatile Organic Compounds (VOCs)	Formaldehyde	Urea-formaldehyde foam insulation* Wood glues** (e.g. plywood and pressed wood/ chipboard) Paint
	Solvents	Varnishes Paint thinners and strippers, glues Air fresheners
	Perfumes	Perfumes, personal care products, Household cleaning products Fabric softeners
	Off-gassing mixtures	Equipment (e.g. computers) Furniture
	Products containing petrochemicals	Carpets Ink from books and periodicals Fuels, petroleum
Combustion products	Tobacco smoke Vehicle exhaust Barbecue or wood smoke	Cigarettes, Buses, trucks, cars Barbecues, wood stoves, fireplaces
Microbial products	Moulds Mycotoxins Bacteria Metabolites produced by moulds or bacteria	Mould or bacteria in structures Mould or bacteria in ventilation and air conditioning systems Microbes in older documents Mouldy furniture Soil (plants)
Pesticides	Insecticides Herbicides Fungicides Algaecides	Products to kill insects Products used to kill weeds Products used to kill fungi Swimming pools products, including chlorine
Natural inhalants	Pollen Animal dander	Tree pollen (Spring) Ragweed (August-September) Dogs, cats, horses, etc.
Foods	Allergenic proteins Preservatives Individual/specific flavouring agents	Peanuts, milk, gluten Sulfites in dried fruits and wine Monosodium glutamate (MSG) Artificial flavours and colours Curry, cinnamon, hot pepper
Electromagnetic radiation	Lighting	Lamps Screens Fluorescent light bulbs
	Radio waves and microwaves	Wiring problems Energy-efficient devices Computers
	Very low-frequency electromagnetic fields	Television Telecommunications equipment Power lines
	Telluric currents	Power supply systems that let the current pass through the ground, pipes or structures
Other factors	Temperature Noise	Workplace or home infrastructure
* Now prohibited in Canada. ** Prohibited in new products in many countries.		Source: Sears, 2007.