Ground-Level Ozone

Ground-level ozone forms when pollutants from cars and trucks, power plants, factories, and other sources come in contact with each other in heat and sunlight. Factors such as weather conditions and intensity of sunlight also play a part in how ground-level ozone is formed. Ground-level ozone is one of the biggest parts of smog, and it is usually worse in the summer months.

Many scientific studies have linked ground-level ozone contact to many problems, such as:

  • lung and throat irritation
  • wheezing and breathing difficulties during exercise or outdoor activities
  • coughing and pain when taking a deep breath
  • worsening of asthma, bronchitis, and emphysema
  • higher chance of respiratory illness like pneumonia or bronchitis

As a result of these studies, scientists know that breathing in too much ozone can increase events such as

  • use of asthma medication
  • absences from school
  • visits to the emergency room and hospital admissions
  • early death from heart and lung disease


Fine Particulate Matter (PM2.5)

Particle pollution, or particulate matter, consists of particles that are in the air; including dust, dirt, soot and smoke, and little drops of liquid. Some particles, such as soot or smoke, are large or dark enough to be seen. Other particles are so small that you cannot see them.

Particles that are 2.5 micrometers in diameter or smaller; are known as Fine Particulate Matter or PM2.5. A typical human hair is 70 micrometers in width, which makes the Fine Particulate Matter about 30 times smaller than the width of a hair strand! Their small size allows them to get into the deep part of your lungs and even into your blood. Being exposed to any kind of particulate matter has been linked to

  • increased emergency department visits and hospital stays for breathing and heart problems
  • breathing problems
  • asthma symptoms to get worse
  • adverse birth outcomes, such as low birth weight
  • decreased lung growth in children
  • lung cancer
  • early deaths