Proposed Air Quality Objectives for Fine Particulate Air Pollution

Abstract

Canada is now considering recommendations of the Federal-Provincial Working Group on Air Quality Objectives and Guidelines to adopt objectives for fine particulates that will be among the most stringent anywhere in the world and that may be technically unobtainable in the short term. No Canadian city would be in compliance at this time if these objectives were adopted. The fine particulate issue is also driving a fundamental change in the way that Canada harmonizes regulations on air pollution. In the United States, standards are set by the federal government for implementation by the states; the federal government has primacy. These standards are mandatory as a minimum level of control, although states may impose more stringent standards. By contrast, in the Canadian system the federal government does not have primacy and environmental protection at the local level is mandated to provincial governments. Canada has chosen to set guidelines negotiated between the federal government and representatives of provincial governments, in the expectation that these guidelines will influence the individual provinces to adopt similar standards. The role of guidelines, as opposed to standards, is to drive voluntary change and to influence public opinion. In the past, these guidelines were set to be more stringent than U.S. National Ambient Air Quality Standards and reflected the reality that urban air pollution levels in most large Canadian cities were generally lower than their U.S. counterparts. In 1997, a new process was initiated to bring the development of recommended air quality criteria into a more scientific formulation. National Ambient Air Quality Objectives will now be developed in a more transparent, accountable and science-based process. They will also be recommended rather than mandated but as objectives will carry the expectation that all jurisdictions in Canada will eventually harmonize their own standards to these norms. The first two objectives under this new process are fine particulates and ozone. For the purpose of this discussion, we shall confine our remarks to fine particulates. A large body of evidence was compiled into a report 1 that constituted the briefing document for a Stakeholder Consultation Workshop convened by the Atmospheric Environment Service of Environment Canada in December 1997. Included in this dossier was the report of the Federal Provincial Working Group recommending new air quality objectives for fine particulates. 2 The implication of these recommendations was staggering. Based on their reading of the available evidence, and driven primarily by estimates of lives saved through reductions in mortality associated with fine particulate levels in urban areas, the Federal Provincial Working Group recommended an objective for PM 10 of a 24hour average concentration of 40 µg/m 3 and for PM 2.5 of 20 µg/m 3 . This compares with the U.S. Environmental Protection Agency’s (EPA’s) previously proposed (now remanded) National Ambient Air Quality Standard of U.S. 24-hour averages of 150 and 65 µg/m 3 , respectively. Canada would have no equivalent to the previously proposed U.S. annual averages of 50 and 15 µg/m 3 , respectively, relying on the 24