What is a code orange alert? What you need to know about today's air quality in NJ

Air quality is expected to take a dive Wednesday in North Jersey and the New York metropolitan region as more smoke from Nova Scotia wildfires is expected to inundate the region.

What does a Code Orange air quality alert mean?

Small particles from burning wood will cause an orange alert for most of New Jersey, according to a forecast from the state Department of Environmental Protection.

Young children, the elderly and those with lung conditions such as asthma and emphysema are particularly vulnerable in an orange alert. They are advised to stay indoors.

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In New Jersey, orange alerts typically happen during the warmest days of summer when smog levels rise to an unhealthy level. The soot from the Nova Scotia fires is called particulate matter - an extremely small piece of burnt material that used to cause problems in New Jersey from coal-fired power plants and old diesel engines but have been abated in recent years.

Why is there smoke in the air today in New Jersey?

A raging wildfire outside Halifax about 600 miles away from North Jersey has burned through 2,000 acres of forest and damaged at least 200 homes and businesses. The fire was expected to spread on Wednesday due to dry conditions and persistent wind, according to the Canadian Broadcast Corporation.

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Smoke arrived in the region Tuesday afternoon propelled by southwesterly winds causing hazy skies across much of the Northeast. The plume was so dense that some residents in New England reported the air smelled like a campfire.

Fire in Nova Scotia second recent wildfire in Canada affecting NJ

This is the second time in two weeks that smoke from a Canadian wildfire has entered New Jersey's air. The first round came on May 22 when smoke from wildfires in Alberta traveled 2,600 miles across the continent. But that smoke was confined to the mid- and upper-atmosphere and did not affect air quality.

May has been extremely dry in the Northeast. It will likely be the dryest May on record in New Jersey, according to The National Weather Service. Lack of rain and humidity helped cause wildfires in the Garden State from Passaic County in the north to Gloucester County in the south.

When will NJ air quality improve?

Wednesday will likely be the worst day of the week. Air quality is forecasted to improve Thursday.

It will plummet again on Friday, but not due to wildfires. Temperatures are expected to rise and so too are smog levels. An orange alert is forecasted for much of the state.

This article originally appeared on NorthJersey.com: Why is the air quality bad today in NJ? What to know