These Counties Have PA's Worst Air Quality Thursday

PENNSYLVANIA —The air is still listed as hazardous in parts of Pennsylvania on Thursday, as officials continue to warn children, the elderly, and those with respiratory conditions to stay indoors.

Smoke from millions of acres burning in eastern Canadian wildfires is lingering above several states on the East Coast this week, making it difficult to breathe and bringing an eerie yellow or gray sky.

A "Code Red Air Quality Action Day" affects Berks, Bucks, Carbon, Chester, Delaware, Lehigh, Monroe, Montgomery, Northampton, and Philadelphia counties until 11:59 p.m. Thursday night according to the National Weather Service.

There are also Code Red Air Quality Alerts in the central and northern mountains of Pennsylvania, the Susquehanna Valley, and northeast Pennsylvania.

"Members of sensitive groups may experience more serious health effects. The effects of air pollution can be minimized by avoiding strenuous activity or exercise outdoors," said the National Weather Service.

Related articles:

• Code Red Issued In PA Over Air Quality, Latest Forecast For Clearing
• When Will The Smoke Clear In PA? Latest Forecast For Thursday

State air quality monitors registered "hazardous" levels over 200 on Thursday afternoon in the Susquehanna Valley according to AirNow.gov, down from more than 300 Thursday morning. The Philadelphia area was registering "unhealthy" air pollution levels of 189 at 1:30 p.m., and Lancaster had dropped out of the "hazardous" air quality level, but still had "very unhealthy" levels of 231. See county-by-county air levels below.

The highest concentrations of wildfire smoke should wane into Thursday afternoon across Pennsylvania, the National Weather Service said, though haze and smoke is expected to become more dense into Thursday evening. There will also be a slight chance of showers before 9 p.m. in southeastern Pennsylvania.

On Friday, levels of particulate matter in the air will still be high enough to impact those in sensitive groups, according to forecasters. Look to the weekend for the first signs of relief, as the NWS said "there should be some reprieve from the smoke through the weekend."

With the amount of smoke and air pollution in the atmosphere through Thursday, it will be difficult for some sensitive groups (children, the elderly, people with breathing conditions) to do normal activities outside. And, even those adults without lung conditions may feel irritation in their eyes, nose, and throat.

Air quality alerts are triggered by a number of factors, including the detection of high levels of fine-particle pollution — known as "PM 2.5" — which can irritate the lungs.

The AQI measures as follows:

• Good/green: 0-50
• Moderate/yellow: 51-100
• Unhealthy for sensitive groups/orange: 101-150
• Unhealthy/red: 151-200
• Very unhealthy/purple: 201-300
• Hazardous/dark purple: 301-500

Here's a look at the air quality in Pennsylvania counties covered by Patch at 1:30 p.m. Thursday, according to AirNow.gov.

• Allegheny: 129
• Beaver: 129
• Bucks: 189
• Butler: 129
• Chester: 181
• Delaware: 189
• Lancaster: 231
• Montgomery: 189

AirNow partners with the U.S. Environmental Protection Agency, National Oceanic and Atmospheric Administration (NOAA), National Park Service, NASA, Centers for Disease Control, and tribal, state, and local air quality agencies.

The frequency, extent and severity of wildfires mark important indicators of climate change, environmental officials say. The peak of the nation's wildfire season is also occurring earlier — peaking in August from 1984-2001 and then in July from 2002-20, according to research from the U.S. Environmental Protection Agency.

For an exact look at when the smoke might clear, here is the forecast in southeastern Pennsylvania through Saturday, per the National Weather Service:

Thursday afternoon
Widespread haze after 2pm. Mostly sunny, with a high near 75. West wind around 10 mph.

Thursday night
A slight chance of showers before 9pm. Widespread haze. Patchy smoke before 9pm. Mostly cloudy, with a low around 50. North wind around 5 mph. Chance of precipitation is 20 percent.

Friday
A chance of showers, with thunderstorms also possible after 2pm. Widespread haze before 1pm. Mostly sunny, with a high near 71. Northwest wind around 5 mph. Chance of precipitation is 50 percent. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

Friday night
A chance of showers and thunderstorms before 11pm, then a slight chance of showers between 11pm and 2am. Partly cloudy, with a low around 50. Northwest wind around 5 mph. Chance of precipitation is 30 percent. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

Saturday
Mostly sunny, with a high near 79. Northwest wind 5 to 10 mph.

Saturday night
Partly cloudy, with a low around 54.

Patch's Nicole Rosenthal contributed to this report.