Health And Air Quality Risk Assessment

This content was archived on June 24, 2013.

Human beings have always been exposed to daily health hazards in air, food, water and the workplace, and almost nothing an individual does is risk-free.

People can choose to avoid a risk or to accept some risk in return for a greater benefit. While each person can choose to avoid or reduce many health risks from the environment (such as choosing not to smoke), the individual is not in control of all risks.

The government, acting in the best interests of the population, must act to reduce certain risks.

Health Canada mandate is to identify health hazards and develop strategies to protect Canadians from these hazards. Health Canada's primary role with repect to air pollution and other environmental hazards is to identify the hazards posed to the Canadian population, and to them use its own Authority or work with other to reduce the identified risk. In the case of air pollution, Health Canada usually works with Environment Canada, the department with the most direct authority to formulate risk management strategies. Protecting health involves several complex procedures that includes identifying health hazards, estimating the level of risk they pose, and developing options to deal with them.  The Department has formalized all of these steps in a process known as the risk management framework, which forms the basis of its health protection strategy.

Scientific determination of a hazard and its potential for damage to human health is a relatively new idea. The risk associated with exposure to a toxic substance depends on both the nature of the adverse health effects that may be induced and the probability of their occurrence.

Several formal models for risk evaluation have been designed in order to provide a consistent methodology and ensure the scientific integrity of an evaluation. Those risk evaluation models may differ from country to country's, but each country's methodology should be clear, logical and consistent. Once available evidence has been weighted, a choice must be made to either eliminate the risk or to accept varying degrees of risk in exchange for varying degrees of benefit.  This balance between risk and benefit in health issues is achieved by Health Canada through a formal process called risk determination. Health Canada has developed it's own risk determination model that provides an analytical, flexible framework for all of its assessment/management decision-making.

A framework was published in 1993 to provide guidance in assessing and managing health risks. A project was undertaken in 1997 to update the framework to ensure transparency by including public involvement and communicating the risk-related information more effectively.  Risk communication refers to an exchange of information concerning the existence, nature, form, severity or acceptability of health or environmental risks.  The revised framework will provide a basis for Health Canada's strategic approach to risk assessment and management.

The Health Canada revised framework consists of a series of inter-connected steps. The process can be subdivided into three phases: issue identification (identify the issue and put it into context); risk assessment (assess risks and benefits); and risk management.  Involvement of the public and affected parties is integrated in all steps. The framework is generally similar to the one created in 1993 with the exception of the first step.

For more information on this topic :

• Identify the Problem and Its Context
  
• Assess Potential Risks and Benefits
  
• Identify and Analyze Options
  
• Select a Strategy
  
• Implement the Strategy
  
• Monitor and Evaluate Results
  
• Involve Interested and Affected Parties

Identify the Problem and Its Context

This first step is to determine the nature of the risk management issue and establish the operating procedures.

Assess Potential Risks and Benefits

The risk assessment phase consists of four steps: hazard identification, hazard characterization, exposure assessment, and risk characterization.  Following the risk assessment, a benefit assessment can also be done to estimate the future health risks and potential benefits through reduced ambient concentrations.  The hazard identification and characterization are primarily based on case reports, toxicological investigations in the laboratory and/or epidemiological studies.  Estimates of exposure toxicity and risk rely on quantitative analysis of epidemiological, toxicological and exposure data.  All analyses are based on the most accurate scientific evidence available, however, often there are gaps in the existing data and modeling may be required to fill the gaps.  An estimate of the level of risk is derived as a final stage.  The risk assessment is peer reviewed by experts within and outside of Health Canada. 

Identify and Analyze Options

At this stage, options for dealing with the risk are developed. These options could be regulatory (new regulations to decrease or eliminate pollutant emissions) or non-regulatory (economic measures, public education, voluntary actions) and may include the option of leaving things as they are. Options are then analyzed from a variety of viewpoints, depending on the particular chemical involved. The analysis may:

• look at the issue from an individual or a social perspective;
• take into account the public's perception of the risk;
• consider the feasibility of the proposed options, their economic and/or environmental impact;
• study the social, political, and cultural implications of each options;
• weigh health risks against health benefits.

Select a Strategy

Once the options are evaluated, a decision is made and the risk management stage can proceed.  These decisions are made by the appropriate authority and the selection of an appropriate risk management strategy will depend on several factors.  A balance between risks and benefits should be sought.

• take into account the public's perception of the risk;
• consider the feasibility of the proposed options, their economic and/or environmental impact;
• study the social, political, and cultural implications of each option;
• weigh health risks against health benefits.

Implement the Strategy

The resources for implementation are committed.  Implementation should particularly stress effective risk communication, a step that, undertaken early, can improve the public's confidence in the authority that made the decision.  The most effective communication tool is clear and simple language.

• take into account the public's perception of the risk;
• consider the feasibility of the proposed options, their economic and/or environmental impact;
• study the social, political, and cultural implications of each option;
• weigh health risks against health benefits.

Monitor and Evaluate Results

The sustainability of the decision is monitored using such techniques as environmental sampling, ongoing epidemiological studies, and evaluation of new information, should such information become available.

Risk management is not a static process.  New, pertinent information about the risks of the particular chemical feed back into previous steps in the process, permitting the decision to be reconsidered in the light of new findings.

• take into account the public's perception of the risk;
• consider the feasibility of the proposed options, their economic and/or environmental impact;
• study the social, political, and cultural implications of each option;
• weigh health risks against health benefits.

Involve Interested and Affected Parties

The integration of risk communication in all steps of the process is an important factor in the transparency of the Health Canada framework.  Public consultations are integrated as much as possible throughout the process.