Environment Canada has issued a special air quality alert for all of New Brunswick as smoke from wildfires in central Canada is being carried over the province.

Smoke will persist over New Brunswick Tuesday night with satellite images showing a smoke plume extending through much of the province, a 3:30 p.m. update to the morning advisory states.

"This smoke may descend close to the ground and reduce air quality for several hours."

According to the Air Quality Health Index, there is a "moderate risk" in smoke province-wide Tuesday, with the exception of the Edmundston region, which is listed as "low."

There are hundreds of wildfires raging between northwestern Ontario and B.C.

Wildfire smoke is a complex mixture of gases, particles, and water vapour that contains ozone, sulphur dioxide, nitrogen dioxide, carbon monoxide, volatile organic compounds and fine particulate matter, according to the federal government's air quality website.

"There is no evidence of a safe level of exposure for most of these pollutants," it says. "This means that smoke can impact your health even at very low levels. Air quality may be decreased even if you can't see or smell smoke."

Some of the more serious symptoms of smoke exposure can include: dizziness, chest pains, severe cough, shortness of breath, wheezing (including asthma attacks), and heart palpitations (irregular heart beat).

"Less commonly, exposure to wildfire smoke can lead to heart attack, stroke and even premature death."

Some of the people considered at higher risk of health problems when exposed to wildfire smoke include those with lung or heart conditions, seniors, infants and young children, pregnant women, people who work outdoors and people involved in strenuous outdoor exercise.

When the risk is moderate, those considered at-risk are advised to consider reducing or rescheduling strenuous activities outdoors if they experience symptoms.

The general population does not need to modify their usual outdoor activities unless they experience symptoms, such as coughing and throat irritation, the website says.

The smoke plume will continue to sweep southeastward Tuesday, according to Environment Canada.

A digital modelling forecast on FireSmoke Canada, an online portal that tracks smoke from wildfires, shows the entire province being enveloped in smoke.

The smoke is expected to move out of the province later Wednesday, which will lead to improved air quality in all areas, Environment Canada said.

The air quality forecast for Wednesday shows "low risk" across the province.