Glossary

Plain-language definitions for the terms used across Public Health Trace -- recall classifications, coverage scope, data source names, and alert options. Every definition below is built from the same source the rest of the site already uses for that term, so this list can never quietly drift from what's shown elsewhere.

Recalls

See Recalls and Methodology for how these are used.

Class I recall: A situation in which there is a reasonable probability that use of or exposure to a product will cause serious adverse health consequences or death.
Class II recall: A situation in which use of or exposure to a product may cause temporary or medically reversible adverse health consequences, or where the probability of serious consequences is remote.
Class III recall: A situation in which use of or exposure to a product is not likely to cause adverse health consequences.
Not yet classified: The agency has not yet assigned a recall classification.
Active recall: Status is not Terminated or Closed.
Nationwide (recall): A recall's distribution description exists but no individual state codes could be extracted from it -- in practice this means a narrative description like "distributed nationwide." An email alert subscriber who chooses to include nationwide recalls is matched to these even though no specific state was named.

Outbreaks and travel health

See Outbreaks and Travel Health for how these are used.

Active outbreak: No end date has been recorded, and the outbreak started within the last 12 months. CDC's outbreak surveillance data has no investigation-status field at all, so recency is the closest honest proxy available.
Provisional data: These figures are provisional and may be revised by the source as more reports come in.
WHO Disease Outbreak News (WHO-DON): Current disease outbreak notices published by the World Health Organization for this country. This also serves as Public Health Trace's recent public-health news feed for this destination -- no separate news source is ingested.
Vector-borne disease notices: WHO outbreak notices for this country that mention a known mosquito- or vector-borne disease, such as malaria, dengue, or yellow fever.

Data sources and coverage

See Data Sources and Data Coverage for the full, current status of every source.

FDA Food Enforcement: openFDA's Food Enforcement dataset -- official FDA food recall records.
FDA Food Safety Recalls (RSS): FDA's public food-safety-recalls RSS feed, a lighter complementary path alongside the enforcement dataset above.
USDA FSIS: USDA Food Safety and Inspection Service (FSIS) meat, poultry, and egg product recalls, retrieved through a CDC-hosted combined food-safety feed after USDA's own API began blocking cloud-origin traffic.
CDC NNDSS: CDC National Notifiable Diseases Surveillance System (NNDSS) weekly case counts by disease and state.
CDC NORS: CDC National Outbreak Reporting System (NORS) -- foodborne, waterborne, and enteric outbreak investigations.
WHO Outbreak News: World Health Organization Disease Outbreak News -- published international outbreak bulletins, distinct from a U.S. investigation feed.
FDA Drug Recall Announcements: FDA's own recall-announcement page, LLM-extracted -- an early-warning companion to the openFDA Drug Enforcement dataset above, which remains the sole authoritative source. A recall can appear here days before the matching openFDA enforcement record exists; these are shown as pending announcements until confirmed matched, never as official enforcement records.
United States coverage: Data specific to the United States -- FDA and USDA recalls, and CDC surveillance and outbreak data.
Global coverage: Data spanning multiple countries, or with no single-country scope -- currently WHO Disease Outbreak News.

Email alerts

See Email Alerts to subscribe.

Immediate delivery: An alert email is sent as soon as something matches your selected preferences.
Daily digest: Matching alerts are combined into one email sent once a day, instead of one email per match.
Weekly digest: Matching alerts are combined into one email sent once a week, instead of one email per match.
Nationwide alerts: Include nationwide recalls even if no state is selected in your alert preferences.

Air Quality

See Air Quality for current conditions, forecasts, and email alerts by AirNow reporting area.

Air Quality Index (AQI): The EPA's standard 0-500 scale for reporting air quality, divided into 6 categories from Good to Hazardous. A higher number means greater health concern.
AirNow reporting area: The geographic area the EPA's AirNow program reports air quality for. A reporting area often covers multiple cities or a wider region -- it is not the same as a single municipality, and is never labeled a "city" on this site.
Good: Air quality is satisfactory, and air pollution poses little or no risk.
Moderate: Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.
Unhealthy for Sensitive Groups: Members of sensitive groups may experience health effects. The general public is less likely to be affected.
Unhealthy: Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects.
Very Unhealthy: Health alert: The risk of health effects is increased for everyone.
Hazardous: Health warning of emergency conditions: everyone is more likely to be affected.
Action Day: A day the source (AirNow or the reporting area's own agency) has declared an air quality advisory for -- shown exactly as the source reported it, never relabeled as an independent EPA advisory by this site.
Preliminary (air quality): This observation or forecast reading is preliminary and may be revised by AirNow.
Primary pollutant: The pollutant AirNow itself designates as the main driver of a reading's air quality category, which can differ from the pollutant with the numerically highest AQI value in the same reading -- both are shown when they disagree.