A third round of in-reservoir turbidity treatment started Wednesday at the North Fork Reservoir, as a crucial measurement on the path toward potable water continues to drop.

Water Resources Department spokesperson Clay Chandler said at Wednesday’s daily Helene briefing that the turbidity measurement, Nephelometric Turbidity Units (NTUs), stood at 14.8 in the morning. A week ago it stood at 18.

“So it’s still falling,” Chandler said.

The city is now filtering about 20 million gallons of water a day through North Fork, which provides 80 percent of Asheville’s drinking water, and another 3 million gallons daily through its Mills River treatment plant. That leaves the water department just 4 million gallons a day short of being able to pressurize the entire system. That’s the threshold for again providing potable water, which the city has not delivered since Sept. 27 when Helene washed out the main transmission lines and a backup line, and essentially turned North Fork upside down.

Besides the turbidity treatment, which involves an application of aluminum sulfate and caustic soda in the reservoir to foster coagulation and sinking of clay particles, the city is also moving forward on a partnership with the U.S. Army Corps of Engineers to provide a portable filtration system that can handle high-turbidity water. While ideally the city needs the NTU level to hit 1.5 to 2.0 for optimum water production, the Corps’ system can handle higher NTU.

Regarding the Corps of Engineers “interim pretreatment system,” Chandler said, “the private contractor who will perform the work conducted a site visit Monday afternoon, and equipment and materials started arriving yesterday.”

The timeline for completion of that project remains the same — late November or early December. That depends on the weather, though.

The city has a two-pronged approach to returning to potable water service: continue reducing turbidity while increasing the amount of water that can be filtered, and installing the Army Corps technology to filter more turbid water.

Chandler has said previously that once the city is pushing enough potable water, it will have to flush the entire system and then repressurize it, which could take two and a half to three weeks. Asked if the city currently being able to push through more water than expected, the 20 million gallons per day, could shorten that flushing timetable, Chandler said, “Theoretically, that’s possible.

“But you know, that’s all going to depend on the back-end bacterial testing that we’ll do once that process starts,” Chandler said. “But theoretically, yes, it could speed it up, but that’s no guarantee.”

Potable water’s return still will likely come in early to mid-December. The water continues to clear, and Chandler said Wednesday that is in part because workers are now seeing much finer silt particles instead of the heavy, muddy material they encountered right after the storm, when North Fork turned completely brown.

The city remains under a boil water notice for all residents. The tap water the city is providing is acceptable for showering, flushing toilets and doing laundry, but residents should use bottled water for consumption. If you must use tap water for consumption, it has to be boiled for at least one minute.

Asheville Watchdog is a nonprofit news team producing stories that matter to Asheville and Buncombe County. John Boyle has been covering Asheville and surrounding communities since the 20th century. You can reach him at (828) 337-0941, or via email at jboyle@avlwatchdog.org. The Watchdog’s local reporting during this crisis is made possible by donations from the community. To show your support for this vital public service go to avlwatchdog.org/support-our-publication/.

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Six weeks after Tropical Storm Helene, sludge from roiling floodwaters has turned into sunbaked dust, brought on by an extended warm, dry spell and repair crews trying to make Asheville and surrounding areas whole again.

Overall particulate levels have not been unhealthy, according to the Environmental Protection Agency’s daily index, but the Asheville Buncombe Air Quality Agency recommends wearing an N95 mask if you’re working in dusty conditions, removing storm debris or cleaning up damage in an enclosed area.

More worrisome to air quality experts is smoke pollution from open burning of storm debris.

“What we’re particularly concerned about is the fine particles from open burning that we expect we’re going to see more of,” AB Air Quality Agency Director Ashley Featherstone said.

Tons of debris are being hauled off for processing, but some of it is being burned. Though open burning is illegal inside Asheville city limits and in other municipalities, burning in unincorporated areas is allowed through permitting.

The Air Quality board prefers that there would be no burning anywhere.

“What we’re telling folks is, please don’t burn,” Featherstone said. “Please put your material out on the curb and let the removal contractors come and pick it up. Can you imagine if everybody started burning the stuff in their yard? It would be terrible.”

From Oct. 3 to Nov. 11, there were nine days when the EPA’s measurement of air-borne particulates – known as the Air Quality Index or AQI – has climbed into the moderate range, meaning that while acceptable, the air could pose a risk for some people, especially those who have respiratory conditions or who are unusually sensitive to air pollution. On all other days, the measurement has been considered good.

But there’s a caveat: Buncombe doesn’t have sensors that show what exactly is in those particles and it has only one particulate measurement station, along with one ozone monitor. Only about 1,000 of the roughly 3,000 counties in the United States have monitoring data, according to the EPA.

“AB Air Quality is aware that there is dust in the air from the flood waters that have receded and are also concerned about particles in the air from open burning of storm debris,” according to a statement from the AB Air Quality Agency. “Dust can contain fine particulate, but also contains particulate matter that is larger than what these monitors measure. Those larger particles are considered less dangerous to human health but can still cause irritation to lungs and upper respiratory systems.”

The AQI is a color-coded system that measures parts per million (ppm) of particulate matter. The higher the AQI value, the greater the level of air pollution and health concern, according to the AQI website.

The system is coded as follows:

• Green (Good) – 0 to 50 ppm
• Yellow (Moderate) – 51 to 100 ppm
• Orange (Unhealthy for sensitive groups) – 101 to 150 ppm
• Red (Unhealthy) – 151 to 200 ppm
• Purple (Very unhealthy) – 201 to 300 ppm
• Brown (Hazardous) – 301 and more ppm

“I haven’t sifted through the long-term data, but I can tell when I check the [air quality sensor] map that particulate matter around the city is a little bit higher than it usually is,” said Evan Cuozo, an atmospheric and environmental scientist by training, a professor at the University of North Carolina Asheville and a member of the AB Air Quality board. “It’s not surprising. There’s a lot of dust in the air. Nothing to be concerned about for long-term health.”

Buncombe doesn’t have sensors that show what exactly is in those particles, according to Cuozo and the AB Air Quality Agency. 

“Certainly we’re breathing in slightly more petrochemicals, pesticides, fuels, solvents, etc.,” Cuozo said. But there aren’t ways to measure how much right now. 

So, is the air safe to breathe, even on yellow-level days?

“I never like to breathe in a lot of dust, so I always try to wear a mask or avoid visible plumes of dust,” Cuozo said. “But I think for acute exposures, short-term exposures, I don’t have any long-term concerns for my health based on this. I think we’re exposed to so many synthetic compounds and plasticizers in our diets and just touching things that I’m not worried about the additional burden in the air right now.”

Tracking smoke

What Cuozo and the AB Air Quality Agency are most concerned about is smoke from open burning of storm debris.

And the risk of wildfires during this dry season is growing, posing perhaps the greatest threat to air quality in the region.

Tree destruction after the storm’s 80-100 mph wind gusts will have long-lasting impacts to the fire environment, the North Carolina Forest Service said in a Nov. 3 warning.

“The potential for increased wildfire activity, especially in WNC, is above normal in November,” the Forest Services said. “In the aftermath of #HeleneNC, the amount of fuel on the ground is excessive.”

Since burning is inevitable, the EPA sent the AB Air Quality Agency several PurpleAir monitors, small portable devices that measure air quality. Five of these were scheduled to be added to Buncombe County in the coming weeks, and some are already running.

“We have four new PurpleAirs installed and showing up on the Air Now Fire and Smoke map at Leicester Library, South Buncombe Library, Biltmore (Hi-Wire) and Board of Education,” Featherstone said Nov. 12.

Having more PurpleAir sensors will allow the agency and the EPA to know whether burning is seriously hurting air quality in areas outside of Asheville and suburban communities.

Anyone can buy a PurpleAir sensor for a little less than $300 and allow EPA to track the data it collects.

PurpleAir sensor data is published live on the brand’s website. EPA also uses PurpleAir sensors in tabulating its own data.

The AB Air Quality Agency has only one fine particulate monitor, which is located at the Buncombe County Schools Board of Education in the Emma community. 

“The Air Quality Index is meant to give an indication of air quality conditions for a general area and does not give specific information on a smaller scale and may not be representative of the air quality in Swannanoa or Fairview for example,” the agency said in an Oct. 22 statement.

Even though AB Air Quality Agency has been tracking and publishing data for many years, Helene has brought it into a new phase where understanding rapidly changing air quality will be vital to understanding how the area is getting rid of its debris.

The effort could last for at least a year, the agency said.

“We’ve heard that the sensors are going to be here for a year,” Featherstone said.

Asheville Watchdog is a nonprofit news team producing stories that matter to Asheville and Buncombe County. Andrew R. Jones is a Watchdog investigative reporter. Email arjones@avlwatchdog.org. Investigative reporter Victoria A. Ifatusin joined us through a fellowship as part of the Scripps Howard Fund’s Roy W. Howard Fellowship program. You can reach her via email at vifatusin@avlwatchdog.org. The Watchdog’s local reporting during this crisis is made possible by donations from the community. To show your support for this vital public service go to avlwatchdog.org/support-our-publication/.

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