The Air Quality Index is compiled by the New Brunswick Department of Environment and is updated three times per day, seven days a week. This index is also referred to as the IQUA, where IQUA stands for "Index of the Quality of the Air". More frequent updates may be made if the index is in the poor or very poor range.

The index is calculated using data collected from stations throughout New Brunswick which include urban stations in Saint John (7), Fredericton (1), and Moncton (1). In addition there are stations in Central Blissville, Pt. Lepreau, St. Andrews, Norton, Fundy National Park, Lower Newcastle, Saint Leonard, and Canterbury that measure only ozone. IQUA values are derived from one or more of the following compounds, depending upon availablity: Nitrogen dioxide, sulphur dioxide, carbon monoxide, ozone, hydrogen sulphide and airborne particles (expressed using a measure called coefficient of haze). The air pollutants on which the IQUA value is based are measured continuously, 365 days per year.

The Air Quality Index for a station that measures more than one pollutant is based upon the pollutant with the highest effective concentration. For example, if 3 pollutants are in the "good" range and one is fair, the index reported for that location would be "fair".

The index is calculated using a standardized approach, based on Canada's National Air Quality Objectives.

IQUA levels may be obtained by calling Environment Canada's weather line. Once connected press 1 for English or 2 for French. The telephone numbers are: Saint John, 506-636-4991; Fredericton, 506-451-6000; Moncton, 506-773-7045; Miramichi, 506-773-7045; Bathurst, 506-548-3220; Caraquet, 506-726-5288; Edmundston, 506-739-1814. The information may also be obtained on the weather channel.

The IQUA system attempts to simplify measurements of individual substances (such as sulphur dioxide or carbon monoxide) into a single number to describe the air quality. Sulphur dioxide and other pollutants present as gases in the air are measured in concentration units such as parts per billion (ppb). For example, a reading of 120 ppb of sulphur dioxide is equivalent to 120 litres of sulphur dioxide in every billion litres of air.

Readings such as this are translated to IQUA numbers using relationships based on the known effects of each substance on human health, vegetation and other components of the environment such as soil, water, materials (e.g. metalwork and masonry), visibility and personal comfort and well-being. Canada's national Air Quality Objectives are based on this same information.

The descriptors, as shown above, given to IQUA ranges (good, fair, poor and very poor) embody a significant margin of safety in terms of effects on human health. Nevertheless, individual sensitivity to all substances present in the environment is highly variable, and individuals may find that they experience perceptible health effects at times when the IQUA is reported to be fair, or even good. This may be due to variations in air quality across the southern New Brunswick region, particular sensitivity to a particular substance, or other factors. For more information on the health impacts of air pollutants, contact your local medical health officer, Department of Health or your family physician.

If the IQUA index exceeds 50 (entering the POOR range), the Department of Environment will inform the district medical health officer, who may issue a public health advisory. The Department of Health and Community Services may also provide further information or advice to the public, depending on circumstances.

To prevent the occurrence of poor IQUA readings, at any time that IQUA values enter the FAIR range, industries are on standby to reduce any emissions which may contribute to poor air quality. The ENV issues all major industries with Certificates of Approval which explain what steps must be taken to reduce emissions at any time. These Approvals are legally binding.

In some cases, activities carried out by ordinary citizens can have a significant effect on local air quality. For example, carbon monoxide and fine particles are emitted in substantial quantities by private motor vehicles, and woodstoves may contribute to particulate levels. Suggestions for the public to take various steps may be issued by the Minister of the Environment during poor air quality episodes.

For more information please contact the New Brunswick Department of Environment, Science and Reporting Branch, at 506-457-4844.