Millions of Americans are expected to face unhealthy air quality during the Fourth of July celebrations as record-breaking heat combines with unprecedented fireworks displays marking the United States’ 250th Independence Day.
Meteorologists and air quality experts have warned that a persistent heat dome blanketing much of the country is likely to trap smoke and pollutants close to the ground, increasing health risks for residents in several major cities.
According to experts, fireworks release large amounts of fine particulate matter (PM2.5), tiny airborne particles capable of penetrating deep into the lungs and aggravating respiratory and cardiovascular conditions. Research indicates that concentrations of these pollutants can rise by more than 40 per cent immediately after major fireworks displays.
The concern is heightened this year as cities prepare some of the largest Independence Day celebrations in US history. Washington, D.C., is expected to stage a Guinness World Record-attempting fireworks show featuring about 850,000 fireworks, while New York, Nashville, Boston, Charlotte and San Francisco have also planned expanded displays.
Environmental scientists said extreme heat will also increase ground-level ozone pollution, which forms when vehicle emissions react with strong sunlight. The combination of ozone, wildfire-like smoke from fireworks and stagnant atmospheric conditions could significantly reduce air quality across many urban centres.
More than 50 million people are forecast to experience triple-digit temperatures during the holiday period, with over 100 daily heat records expected to be broken, particularly across the eastern United States. Washington, D.C., could record its hottest Fourth of July on record, while cities including New York, Philadelphia and Boston are also forecast to endure unusually high temperatures.
Experts warned that calm winds associated with the heat dome may allow smoke from fireworks to linger for several hours or even into the following day, potentially obscuring displays while prolonging exposure to harmful pollutants.
Health authorities advised pregnant women, young children, older adults and people with asthma or other respiratory conditions to limit outdoor exposure if air quality deteriorates. Officials also recommended monitoring local air quality advisories, staying indoors where possible and using properly fitted N95 masks if pollution reaches unhealthy levels.
