Air quality objectives and standards

Air quality objectives and standards are in place for pollutants to avoid potential impacts to the natural environment, to human health, or to avoid nuisance dust or odour. New Brunswick has formally adopted and reports on air quality objectives for five pollutants. These are established as regulated Maximum Permissible Ground Level Concentrations under the authority of the Clean Air Act. 

In addition to the provincial objectives, New Brunswick reports on four pollutants with respect to the Canadian Ambient Air Quality Standards (CAAQS). These provide a common benchmark for air quality across Canada and have been adopted by the Canadian Council of Ministers of Environment as part of an overarching Air Quality Management System (AQMS) for Canada. 

The standards have been adopted in federal regulation under the Canadian Environmental Protection Act as non-binding standards. Although compliance to these standards is not a regulated requirement in New Brunswick, the provincial government continues to work towards achieving them.

*The provincial objectives for sulfur dioxide are 50% lower (stricter) in Saint John, Charlotte and Kings Counties.

As shown in the table above, some pollutants are covered by both federal the provincial standards. They are different because they are calculated differently and serve different purposes. 

The provincial objectives include short-term averages, which makes them useful for real-time compliance monitoring. Achievement can be monitored hour-by-hour, which allows for immediate corrective actions to be taken in response to real-time data.

In contrast, the Canadian Ambient Air Quality Standards include more complex calculations and their achievement can only be determined once per year. Their strength is in long-term air quality management and planning. They are designed to detect real changes in overall air quality and to disregard the effects that unusual weather variations can have on monitoring results. They also have the benefit of being comparable to calculations used in other jurisdictions like the United States.

Both the provincial objectives and federal standards share common goals of protecting human health, guiding regulatory decision-making and informing long-term air quality planning decisions.

There is often more than one objective and standard for a given contaminant (e.g. an hourly objective and an annual objective). This is because most pollutants can cause more than one type of environmental or human health impact, which is primarily linked to length of exposure. Setting more than one objective ensures that the different exposure scenarios are addressed.

For example, a pollutant could cause lung irritation when people are exposed even briefly to concentrations above a certain value. In this case a short-term exposure objective, such as a one-hour average concentration, might be established. The same contaminant could also be known to cause another type of health impact but only through constant exposure. In this case, the second impact might occur at a much lower concentration. In this case a second, long-term exposure objective, might be established such as an annual average concentration.

In this example, compliance with the first objective would be determined on an hour-by-hour basis. This means that there are 8,760 opportunities for compliance/exceedance each year. However, compliance with the second objective can be determined only once per year. 

Importantly, it would be possible to achieve the first objective in each of those 8,760 measurements but still fail to meet the second objective. Similarly, it would be possible for the first objective to be exceeded many times throughout the year but nevertheless meet the second objective. This is why it is important to have both.

The Air Quality Management System provides a colour-coded management level system for grading air quality. These are shown below. Under the system: 

• green is best and indicative of pristine undeveloped areas
• yellow and orange are progressively poorer and 
• red (CAAQS exceedance) is worst

Generally, poorer air quality is intended to trigger more aggressive action to improve air quality. The colour-coded management levels are meant to encourage continuous improvement (toward green status) for all of Canada.

For pollutants with more than one metric (i.e., an annual and a daily metric), only one management level is determined, which is based on the poorer of the two calculated values.

Some events that impact air quality, like the flow of pollution into our air zones from other parts of the world, or from forest fires, are beyond the ability of government or regulated industries to reasonably control. Nevertheless, from an environmental and human health perspective, these emissions are no different than any other pollution. This is why when determining if the standards have been achieved, it is based on all air quality measurements regardless of these possible events. However, when determining the management levels, the impact from these exceptional events can be removed from the datasets and adjustments can be made where appropriate. For this reason, the values calculated to determine achievement can be different than the values calculated to determine a management level.

Each year, every air zone in Canada is given an overall management level under the Air Quality Management System. This level is based on the monitoring station in the zone with the highest (worst) readings.

This does not mean the entire zone has poor air quality—it simply helps identify the types of management actions that may be needed in that area. Additional information is available at the CCME web site.

In addition to its network of permanent air quality monitoring stations, the department also leads a variety of special air quality monitoring projects across the province using its mobile air quality monitoring unit.

Special studies are typically used to:

• assess air quality near pollution sources
• evaluate potential sites for permanent monitoring stations
• verify air quality modelling predictions
• measure background (baseline) air quality levels prior to a development

Results from special studies may be reported in separate stand-alone reports, which can be accessed at the Department of Environment and Local Government publication page.

Some air pollutants can be transformed in the atmosphere into acidic particles that ultimately fall out as acid rain (or snow, hail, etc.). The emissions that cause acid rain typically travel long distances, hundreds or even thousands of kilometers, before returning to the surface as rain or snow. 

The adverse impacts of acid rain have been recognized since the early 1980s. Acid rain harms sensitive ecosystems by changing the chemistry of lakes, streams and forest soils. It can also damage trees and agriculturally important plants. Infrastructure is also impacted by acid rain, as it can degrade paints and protective coatings, which accelerates corrosion.

Measures to reduce the emissions that contribute to acid rain have been undertaken in North America since the late 1980s. Most recently, this has included commitments to reduce emissions under the Canadian Council of Ministers of Environment’s Post-2000 Canada-wide Acid Rain Strategy (PDF 126 KB). Over the past two decades emissions from major sources within New Brunswick have been reduced significantly.

The department has operated an acid precipitation (rain and snow) monitoring network since the early 1980s. Samples are collected in many sites by a local site operator every day and sent to the provincial laboratory for analysis. The department’ staff coordinate the monitoring program, perform data quality assurance and maintain the official data archive.

The key indicators for acid rain are sulphate and nitrate concentration. Each of these parameters has a slightly different effect on acidity but can be combined and expressed as milliequivalents per litre (meq/L).

Each year since the Clean Air Act came into force, a report is published respecting the province's success in meeting its regulated air quality objectives. This report can be found on the Department of Environment and Local Governments publications page.

New Brunswick operates an online Air Quality Data Portal that provides access to current and historic monitoring results at each of the provincially and industry operated monitoring stations. Results are updated automatically every hour.

The Air Quality Health Index (AQHI) was designed by Health Canada to help communicate air quality information. It converts air quality data for key air pollutants into a single number. New Brunswick shares its air quality data with Health Canada to allow them to calculate hourly AQHI values for New Brunswick. Health Canada also works with Environment and Climate Change Canada to generate AQHI forecasts and provides health-related messaging to accompany the AQHI values. This helps to describe what the numbers mean in terms of health risks and how best to respond to those risks to avoid health problems.

AQHI values are updated every hour and forecasts are issued daily.