The Ministry of Environment has issued a smoke advisory for Williams Lake and surrounding areas because of wildfire smoke affecting air quality.
People are advised to avoid strenuous outdoor activities.
"Last night the peak in the hourly average was 161 micrograms per cubic metre and then over the morning we're down to 97 but that's still well above the objective of 25," MOE quality meteorologist Ralph Adams said Wednesday.
In laymen's terms that measurement refers to the concentration of smoke particles in the air per cubic metre and under normal conditions this time of year the numbers would be between six and 10.
"But to put it into perspective, in the Chilcotin during the 2010 fires, the values were up into the 300-range," Adams said. "These are high values though and the only time we see those is when we have smoke from large aggressively growing fires moving across the plateau and affecting the communities.
There has been a slight switch in wind direction, which can result in dramatic changes, he said, adding it remains to be seen what's going to happen and whether there will be a change in the weather.
Rain has been forecasted for Friday and Saturday in Williams Lake.
"There is likely to be smoke for at least the next 24 hours, but the problem with wildfires is it can change from minute to minute."
If the wind changes values will drop, he explained.
People experiencing difficulties breathing, chest pain or discomfort, and sudden onset of coughing or irritation of airways, are encouraged to check with a health care provider.
"Exposure is particularly of concern for infants, the elderly and those who have underlying medical conditions such as diabetes, and lung or heart disease."
The ministry has also received reports from people living north of Williams Lake receiving large quantities of ash on their properties, Adams said.
There will be an update to the advisory later today, he added.