Shipley Farms · Vilas, Watauga County, North Carolina
The air on 115 acres
This is the one measurement around this farm that is unambiguous good news. Fine particle pollution at the nearest long-running rural monitor has fallen by nearly two-thirds since 2000, and peak ozone is down by a fifth to a third since 1990.
- Fine particles µg/m³ PM2.5, annual mean
- Change since 2000 at Linville Falls, 34.6 km
- Peak ozone ppb, against a standard of 70
- Monitors in this county
- Centroid 36.2466° N, 81.7504° W
- Elevation 2,896 ft / 883 m
- Tract 115 acres / 46.5 ha
- Record 1990–2025, EPA AQS
Thirty-five years of cleaning up
No monitor has ever stood on this farm. The relevant records are a regulatory PM2.5 monitor at a school in Boone, km away, which ran from 2002 to 2015; a rural PM2.5 and ozone site at Linville Falls, km south, running continuously since 2000; and ozone at Cranberry and Lenoir going back to 1990.
Fine particles and ozone, 1990 to 2025
Left axis: annual mean PM2.5 in micrograms per cubic metre. Right axis: the fourth-highest daily maximum eight-hour ozone in parts per billion, which is the form the air quality standard takes. Dashed lines are the current national standards.
Hover a year, or focus the chart and use the arrow keys, to read every station.
Both declines are the Clean Air Act working on coal-fired power. Sulphur dioxide and nitrogen oxide controls on Appalachian and Ohio Valley plants through the 2000s cut the sulphate that makes up most of the region’s fine particle mass, and the nitrogen oxides that make summer ozone. The steepest part of both curves is 2007 to 2012, which is exactly when those controls came on.
Linville Falls now averages micrograms per cubic metre, well under the annual standard of 9.0 that EPA tightened in 2024, and among the cleanest readings in the eastern United States. Peak ozone there was parts per billion against a standard of 70. Thirty years ago Lenoir recorded 98, which was a violation.
from to µg/m³, 26 years of record
from to ppb, 32 years of record
from to µg/m³, then the monitor closed
Smoke is the hazard, not industry
Every bad air day in this record is fire. There is no factory upwind of this farm and no coal plant close enough to matter any more. What is left is smoke, and smoke arrives from a long way off.
The dirtiest days on record
Highest daily PM2.5 at Linville Falls, 34.6 km from the farm, from the years sampled daily for this page. The dashed line is the 24-hour national standard of 35 µg/m³.
| Date | PM2.5 | Multiple of the annual mean | What was happening |
|---|
The worst day in the record
reached micrograms per cubic metre — above the 35 microgram daily standard and times the annual average — during the November 2016 Southern Appalachian wildfires. The 2023 Canadian smoke episodes were less extreme day to day but lasted far longer: they pushed the annual mean up a full microgram, erasing roughly eight years of progress in one year.
Helene did nothing to the air
The storm that put eight mudslides on this farm and dropped 17.79 inches of rain in a week registered a peak of micrograms per cubic metre — an ordinary day. Rain scrubs particles out of the air. The event that did the most physical damage in the farm’s recent history was, by this one measure, among its cleaner weeks.
Nobody has measured here since 2015
Watauga County has no PM2.5 monitor
The Boone monitor, km from this farm, closed after 2015, reading micrograms per cubic metre in its final year. There has been no PM2.5 monitor anywhere in the county for more than a decade.
UNKNOWN Every current figure on this page therefore comes from Linville Falls, 34.6 km away and about 500 m lower, on the other side of the Blue Ridge escarpment. Over the fourteen years both were running, Boone read times Linville Falls — consistent with a small town being slightly dirtier than a national park overlook. Applying that ratio to today is an assumption, not a measurement.
The specific thing a distant rural monitor cannot see is local wood smoke during winter inversions, which this valley gets and which is the most plausible local air quality issue here. A low-cost sensor on the farm would answer it in one heating season.
How these figures were built
All values are from the U.S. EPA Air Quality System pre-generated annual and daily summary files, 1990–2025, filtered to monitors within 60 km of the tract centroid. PM2.5 is the annual arithmetic mean of 24-hour samples; ozone is the fourth-highest daily maximum eight-hour average, which is the statistic the national standard is written against. Monitor-years below 75 per cent completeness are excluded.
Linville Falls samples PM2.5 roughly one day in three, so the “dirtiest days” list is the worst of the days that were sampled, not necessarily the worst days that occurred.
Known limits
UNKNOWN Nothing here is measured on the tract. The nearest current monitor is 34.6 km away.
UNKNOWN Causes of individual bad days. Where the table says “not attributed”, it means no documented regional event was confirmed for that date, not that one did not occur.
Agricultural sources are not covered. Ammonia, dust and the farm’s own equipment are not in any of these records. Neither is radon, which is an indoor air question and a real one in this geology.
Sources
- Air quality
- U.S. EPA Air Quality System pre-generated annual and daily summary files, 1990–2025.
- Monitors
- Boone 37-189-0003 (8.3 km, closed 2015); Linville Falls 37-011-0002 (34.6 km); Cranberry 37-011-0003 (30.8 km); Lenoir 37-027-0003 (39.8 km).
- Standards
- PM2.5 annual primary standard 9.0 µg/m³ (lowered from 12.0 in February 2024); 24-hour standard 35 µg/m³; ozone eight-hour standard 70 ppb.
- Position
- Tract centroid as used throughout this site’s weather pages.
Shipley Farms, 1699 Linville Creek Rd, Vilas, NC 28692. Five generations in Watauga County since 1872. All measurements on this page describe the 115-acre home tract at 36.2466° N, 81.7504° W.
No shortcuts since 1872