July 03, 2002

Smog advisory information


NEWMARKET - York Region Health Services offers residents information to become better informed and protected from the harmful effects of exposure to smog.

During the warm summer months, York Region may experience periods of smog that can cause air quality to fall well below acceptable standards. Smog is a combination of airborne pollutants that affect our health and our natural environment. Most harmful are ground-level ozone and fine airborne particles that, once inhaled, can introduce harmful mixtures of chemical compounds into our lungs.

Smog most often occurs on hot, humid summer days. Ground level ozone forms when nitrogen oxides and volatile organic compounds react together in the presence of intense sunlight. Smog levels are influenced by factors such as weather systems and airflow patterns. High levels of smog are often removed after a heavy rainfall.

In some people, even mild exposure to ground level ozone can cause eye, nose and throat irritations, coughing, wheezing and shortness of breath. Smog can lower resistance to infection and can cause illness in people with heart and lung conditions. Those at particular risk include young children, the elderly, asthmatics and anyone with existing respiratory or coronary conditions.

Smog levels are monitored. The Air Quality Index (AQI) is a rating scale that measures outdoor air quality in Ontario. The AQI translates pollutant levels into numbers to determine whether the air quality is considered to be "good," "moderate" or "poor." Generally, the lower the AQI the better the air quality.

The AQI program is managed by the Ministry of the Environment and Energy (MOEE). The MOEE conducts hourly readings of the most common air pollutants year-round at 36 sites province-wide and provides as many as six public reports per day during May to September. A Smog Alert is declared if forecasts indicate the AQI may exceed a reading of 50 in a given geographic area.

The MOEE issues two kinds of Smog Alerts. A "smog watch" indicates a 50% chance that poor air quality will occur within the next three days. A "smog advisory" is issued when there is a high probability that there may be poor air quality within the next 24 hours due to ground-level ozone and particulate matter.

During a Smog Alert, the public is advised to take precautions to minimize exposure to air pollutants and to refrain from activities that could worsen air quality. The following is suggested

to protect those most affected by smog:

Individuals and businesses can make a big difference in helping to reduce smog levels, including:

For further information on air quality issues or a copy of the newly-released Smog Alerts booklet, contact York Region Health Services Health Connection at 1-800-361-5653 (toll free) or


To find out what the current Air Quality Index (AQI) readings are for York Region, contact the Ministry of the Environment and Energy (MOEE). The MOEE posts air quality reports and 3-day forecasts at www.airqualityontario.com. Residents can be directly notified of Smog Alerts by registering for the Smog Alert by Email service on the provincial website. Air quality reports are also available by dialing 416-246-0411 or 1-800-387-7768 (in French 1-800-221-8852).

For more information on The Regional Municipality of York, the services we offer and links to our nine area municipalities, please visit our website at www.region.york.on.ca.

Contact: Kim Clark, York Region Health Services

905-830-4444 Ext. 4101


Under Media Releases - York Region joins area municipalities to sign Declaration on Clean Air

(Attachment - Municipal actions to improve air quality in York Region)

June 21, 2002

The Regional Municipality of York is committed to providing cost-effective, quality services that respond to the needs of our rapidly growing communities.  York Region is comprised of the following nine area municipalities:  Aurora, East Gwillimbury, Georgina, King, Markham, Newmarket, Richmond Hill, Vaughan and Whitchurch-Stouffville.  For more information, visit our Web site at:  www.region.york.on.ca

Contact: Patrick Casey, Senior Media Relations Specialist, York Region

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