It's a 340-kilometre drive from Vancouver to Ashcroft and 548 kilometres from Vancouver to Williams Lake.

But that doesn't mean the B.C. wildfires aren't having an impact on the Lower Mainland.

Today, Metro Vancouver issued an air quality advisor extending across the region and into the Fraser Valley because of the high concentration of fine particulate matter.

It's blown into this region as a result of the fires raging in other areas of the province.

People with chronic medical conditions should put off strenuous exercise as long as the advisory is in place.

"Exposure is particularly a concern for infants, the elderly and those who have diabetes, and lung or heart disease," Metro Vancouver stated in a news release. "If you are experiencing symptoms such as chest discomfort, shortness of breath, coughing or wheezing, follow the advice of your health-care provider."

Fine particulate matter, a.k.a. PM_2.5, is solid or liquid liquid droplets with a diameter of 2.5 micrometres or less. They can be lodged deeper in the lungs because of their tiny size. 

"The PM_2.5 currently impacting our air shed is primarily smoke that has been transported into our region from wildfires burning in the interior of B.C.," Metro Vancouver said.

Poor air quality can be fatal

UBC researchers Michael Brauer and Chris Carlsten described the far-reaching health effects of poor air quality an essay called "Clearing the Air" in a new book by the Peter Wall Institute for Advanced Studies. 

"The latest estimates from the Global Burden of Disease suggest nearly eight thousand Canadian deaths annually (approximately 3 percent of the total) are related to air pollution, ranking tenth among all risk factors for death in Canada," they write in Reflections of Canada. "Air pollution causes more death than motor vehicle collisions, suicide, and HIV combined."

Brauer and Carlsten note in their essay that "a warmer climate portends worsening of air quality" because this has resulted in a longer forest-fire season. And that, they write, "is clearly linked to increased deaths and exacerbation of lung disease".