Highsmog

Highsmog is a term describing episodes of unusually high smog concentrations in a city or region. During highsmog events, fine particulate matter (PM2.5 and PM10) and related pollutants exceed typical levels for days or weeks, reducing air quality and visibility. The term appears in scientific and media sources to convey severity, but it is not a formal regulatory category in most places.

Causes include increased emissions from vehicles, industry, and biomass burning, combined with meteorological conditions that limit dispersion. Temperature inversions, low wind speeds, and stagnant air can trap pollutants near the surface, while regional transport can spread smoke and gases from distant sources. Forest fires and agricultural burnings are common triggers that intensify highsmog episodes.

Characteristics and duration: highsmog episodes typically last several days to weeks and occur in various seasons depending on climate. They feature elevated PM2.5 and PM10 levels, and may involve higher ground-level ozone in some regions. Visibility is often reduced, and small-scale weather patterns strongly influence severity.

Impacts and responses: health risks rise for children, the elderly, and people with asthma or heart disease, while outdoor work and travel can be disrupted. Authorities issue air quality advisories, encourage staying indoors and using filtration, and implement temporary emission controls, traffic restrictions, or industrial measures to reduce further pollution.

Monitoring and management: air quality networks, satellite data, and models help predict highsmog events. Long-term strategies focus on reducing emissions, improving transit, and land-use planning to minimize peak concentrations and protect vulnerable populations. See also: smog, air quality index, PM2.5.