Formaldehyde in the household

Formaldehyde in the household

Introduction

Formaldehyde is a colourless gas that is emitted mainly from household products and building materials. Low levels of formaldehyde in indoor air are actually very common. When found at high levels in air, it can be detected by a sharp smell. High concentrations of formaldehyde can cause irritation of the eyes, nose and throat and can worsen asthma symptoms in children and infants. Formaldehyde can enter indoor air in two ways: from emissions arising from construction materials and household products: off-gassing; from burning materials: combustion. Low levels of formaldehyde in indoor air are actually very common and come from sources including: pressed wood products that use glues that contain formaldehyde, such as particle board, hardwood, plywood paneling, and medium density fibreboard. These products may be used in home construction and renovations, and are also often used to make furniture and cabinets; (Patel, Alkesh 2007, 45-98)

paints, adhesives, varnishes and floor finishes;

household products such as wallpaper, cardboard and paper products;

vehicle exhaust from attached garages or from outdoors;

smoke from fireplaces and wood-burning stoves; and

tobacco smoke.

In general, formaldehyde off-gassing sources emit less and less formaldehyde over time. However, it can take weeks - and sometimes even months or years - to disappear completely.

Formaldehyde is an irritant, and exposure to high concentrations of formaldehyde can cause burning sensations in the eyes, nose and throat. Long-term exposure to moderate formaldehyde concentrations (at levels lower than those causing irritation) may also be linked to respiratory symptoms and allergic sensitivity, especially in children. (Patel, Alkesh 2007, 45-98)

At very high concentrations, formaldehyde can cause cancer of the nasal cavity. It has been linked to this rare type of cancer in industry workers who are regularly exposed to high levels of formaldehyde (higher levels than most people are ever likely to encounter in their homes). The risk of developing cancer from formaldehyde exposure at concentrations found in most Canadian homes is essentially zero. (Patel, Alkesh 2007, 45-98)

Explanation

Health UK's Residential Indoor Air Quality Guidelines

Health UK has developed an indoor air quality guideline for formaldehyde in residences. The guideline sets recommended maximum formaldehyde levels for two types of exposure:

The short-term exposure limit protects against health problems that may arise from exposure to high levels over a short time period (e.g. one hour). This type of exposure could occur, for example, when working with paint or varnish containing formaldehyde.

The long-term exposure limit protects against health problems that may be caused by repeated exposure to lower levels of formaldehyde over a long period (days, weeks, months, etc.). Since formaldehyde levels change over time, with occasional peaks and valleys, long-term exposure levels are best measured by sampling indoor air over a longer period (8 hours or more).

To avoid possible eye, nose and throat irritation from short-term exposure, indoor air levels of formaldehyde should be below 123 µg/m3 (100 ppb). This is actually lower than the formaldehyde level that has been shown to cause irritation in scientific studies. The lower value was chosen to be more protective of health, ...