Concentration of CO2 in the Atmosphere

EPA Reminds New Englanders to Use Free Air Quality Monitoring Tools this Summer

With the onset of warmer weather, the U.S. Environmental Protection Agency urges New Englanders to be aware of the increased risk of ground-level ozone (often referred to as smog) and fine particle air pollution, especially when combined, and to take precautions when air quality levels are predicted to be hazardous. EPA and the New England states continue to offer free resources and tools for the public to monitor the latest air quality forecasts.

“The New England States have made great strides in reducing air emissions, but ozone air pollution continues to be a significant public health issue in our communities,” said EPA New England Regional Administrator David W. Cash. “We also know that many historically underserved communities have suffered from exposure to more air pollution over the years and may also suffer from higher asthma rates. When air quality is poor, we can all take individual actions to reduce our emissions that contribute to air pollution, such as reducing energy use and driving less,” Cash said.

Warm summer temperatures aid in the formation of ground-level ozone. The current ozone standard, set in 2015, is 0.070 parts per million (ppm) on an eight-hour average basis. Air quality alerts are issued when ozone concentrations exceed, or are predicted to exceed, this level. EPA’s New England office posts a list of exceedances of the ozone standard, by date and monitor location, at Current AQI in New England.

Although the number of unhealthful days varies from year to year due to weather conditions, New England has experienced a significant decrease in the number of unhealthful ozone days over the long term. For the 2015 ozone standard, New England had 118 unhealthful days in 1983, compared with 21 in 2023. This downward trend is mainly due to a reduction in emissions from powerplants, mobile sources, and other industrial facilities. Despite this progress, we continue to work in partnership with our states to reduce the number of unhealthful air-quality days across New England, particularly in southern New England.

As climate change increases the probability of unseasonably warm weather and wildfires, poor air quality events are predicted to increase in frequency. Between March and September 2023, there were 12 days in which fine particulate matter (PM2.5) monitors recorded PM2.5 concentrations above levels to be considered healthful. In addition to hazy skies and reduced visibility, wildfires from Canada elevated the 24-hour PM2.5 concentrations for New England. PM2.5 are inhalable particles with diameters that are generally 2.5 micrometers and smaller. For reference, the largest PM2.5 particles are about 30-times smaller than a human hair. EPA and the U.S. Forest Service developed a map to give the public information on fire locations, smoke plumes, near real-time air quality and actions to take to protect your health in one place. The map is available at

Pollution sources that contribute to smog formation are diverse. They include cars, motorcycles, trucks, and buses; industrial sources; and fossil-fuel burning at electric generating stations, particularly on hot days. Smaller sources, such as gasoline stations and print shops, and household products such as paints and cleaners, as well as gasoline-powered lawn and garden equipment, also contribute to the formation of smog.

Here are some of the actions everyone can take to reduce air pollution:

  • Use public transportation, bike, or walk whenever possible.
  • Combine errands and carpool to reduce driving time and mileage.
  • Avoid using small gasoline-powered engines, such as lawn mowers, string trimmers, chain saws, power-washers, air compressors, and leaf blowers.
  • Avoid outdoor burning, including leaf burning and use of firepits and campfires.

In addition, during poor air quality events, it is important to reduce household energy usage, such as setting air conditioners to a higher temperature, and turning off unnecessary lights, equipment, and appliances. EPA’s ENERGY STAR Program also provides trusted guidance and online tools to help homeowners make smart decisions about improving the energy efficiency of their homes.

In March 2023, EPA finalized federal plans that would cut pollution from power plants and industrial sources that significantly contribute to unhealthy levels of ground-level ozone, or smog, for millions of Americans who live downwind from those facilities. This “good neighbor” policy will help air quality in many areas of New England. Also, on March 20, 2024, EPA finalized standards to further reduce harmful air pollutant emissions from light-duty and medium-duty vehicles starting with model year 2027. On March 29, 2024, EPA also issued a final rule to revise existing standards to reduce greenhouse gas emissions from heavy-duty vehicles in model year 2027 and set new, more stringent standards for model years 2028 through 2032.These new vehicle standards will help ensure that air pollution levels improve over the years to come.

Poor air quality affects everyone, but those who are active outdoors or have respiratory diseases, such as asthma, are more sensitive. When air quality is predicted to be “unhealthy for sensitive groups,” EPA and states announce an air quality alert for the affected areas. On these days, EPA recommends that people in these areas limit strenuous outdoor activity and asks that the public and businesses take actions to help reduce air pollution and protect public health.

Tools and information:

Real-time ozone data and air quality forecasts for New England air quality:

National real-time air quality data (free iPhone and Android apps)


Air Quality Alerts from EnviroFlash:

AirNow Fire and Smoke Map:


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