How Does Air Get Polluted?
Ground-level ozone pollution is formed when NOx (nitrogen oxides) and VOCs (Volatile Organic Compounds react with the ultraviolet rays from the sun. NOx is produced primarily by combustion engines, including heavy-duty trucks, cars, power plants, agricultural equipment, construction equipment, and even lawn mowers.

Why Does the Sacramento Region Have an Air Quality Problem?
The Sacramento region consistently ranks in the top 12 areas in the country in the number of days per year when air quality doesn't meet federal health standards. The highest levels of pollution occur in the summer when direct sunlight and strong inversion layers trap pollutants close to the ground.

Drivers in the Sacramento region travel almost 50 million miles each day and our population is expected to grow by one million by 2022. It's not surprising that about 70 percent of our ozone problem is caused by vehicles and other mobile sources, including heavy-duty trucks, buses, agricultural equipment, construction equipment, recreational powerboats, and gas-powered lawn and garden equipment.

What Are the Health Effects of Air Pollution?
Air pollution-related symptoms such as watery eyes, coughing or wheezing can affect everyone. Even for healthy people, polluted air can cause respiratory irritation or breathing difficulties during exercise or outdoor activities. Your risk depends on your current health status, the pollutant type and concentration, and the length of exposure to the pollution.

People most susceptible to severe health problems from air pollution are:

• Individuals with heart or lung disease
• Individuals with respiratory problems such as asthma or emphysema
• Pregnant women
• Outdoor workers
• Children under age 14, whose lungs are still developing
• Elderly residents, whose immune systems are weaker
• Athletes who exercise vigorously outdoors

High air pollution levels can cause immediate health problems:

• Aggravated cardiovascular and respiratory illness
• Added stress to heart and lungs, which must work harder to supply the body with oxygen
• Damaged cells in the respiratory system