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Close to 500,000 residents in the United States have been urged to remain indoors and keep their windows closed due to a significant increase in airborne toxin levels along the Gulf Coast.
Air quality monitoring systems have identified a 150-mile-wide plume of polluted air stretching across areas of Louisiana, Texas, and Arkansas as of Thursday morning.
The most severe pollution levels have been recorded over Shreveport in northern Louisiana, affecting over 380,000 people living in the broader metropolitan area.
Several air quality assessment organizations have classified the air in this region as ‘very unhealthy,’ citing a marked increase in fine particulate matter, known as PM2.5.
These tiny particles, composed of toxic compounds or heavy metals, are typically generated by industrial operations and vehicle emissions. They are small enough to penetrate deep into the lungs, potentially leading to inflammation, respiratory issues, and other health complications.
In Shreveport, the air quality index (AQI) has risen to 250, according to the World Air Quality Index project, a nonprofit providing real-time air pollution data for hundreds of countries.
Air quality levels are measured on a scale from 0 to 500, with zero being the healthiest. When outdoor air quality approaches the 300 to 500 hazardous zone, the US Environmental Protection Agency warns that everyone should avoid all physical activity outside.
The Louisiana Department of Environmental Quality confirmed that PM2.5 had risen into the danger zone for human health.
More than 380,000 people live in the Shreveport–Bossier City metropolitan area (Pictured)
A large plume of air pollutions has formed over parts of Louisiana, Texas and Arkansas on Thursday, May 7
Air pollution at this level can cause respiratory issues such as asthma to worsen and contribute to heart attacks and strokes that cause premature death. However, people without health issues will have problems breathing in PM2.5 at these levels.
AccuWeather warned in an alert: ‘Healthy individuals are likely to experience difficulty breathing and throat irritation; consider staying indoors and rescheduling outdoor activities.’
While microscopic particles of PM2.5 were driving the air quality alerts Thursday morning, AccuWeather also noted that levels of larger particles, known as PM10, have also risen into the ‘unhealthy’ range.
PM10 is a type of particulate matter made up of tiny solid particles or liquid droplets floating in the air that are less than ten micrometers in diameter, thinner than a human hair, but still noticeably larger than PM2.5.
Based on the readings taken over Shreveport, the high concentration of air pollution has been boosted by a condition called stagnant air, where little to no wind and high atmospheric pressure trap pollution near ground level.
To understand the impact of stagnant air on major cities, it is helpful to look at atmospheric pressure. Pressure is measured in millibars, with normal sea-level pressure being 1,013 millibars.
Anything between 1,015 and 1,020 millibars is considered a high-pressure system, with strong pressure exceeding 1,030 millibars. The atmospheric pressure in Shreveport Thursday morning had reached 1,019.
High humidity, typically anything over 60 percent, also plays a major role in trapping air pollution near the ground, as it naturally makes the air ‘thicker.’ In Shreveport, the National Weather Service noted that humidity in the area had risen to 83 percent.
Air quality readings in Shreveport rose to 250, with the major pollutant being fine particulate matter (PM2.5)
Anyone with heart or lung disease, older adults, children and pregnant people could be especially at risk to this concentrated air pollution and should remain indoors and keep their activity low.
Health officials also urge everyone within these zones to keep windows and doors closed to limit outdoor pollution from leaking inside. Using air conditioners or air purifiers can help as well.