Allergies -- Or That Air Freshener?

Those scented candles and air fresheners you use to keep away stale odors might actually be doing a number on your health if you have allergies, experts say.

Allergists at the annual meeting of the American College of Allergy, Asthma and Immunology (ACAAI) reported that people with allergies may be more sensitive to these scents than they realize.

They can "trigger allergy symptoms, aggravate existing allergies and worsen asthma," Stanley Fineman, M.D., president-elect of the ACAAI, said in a statement.

The problem is that some of these products contain compounds that have been shown in research to increase asthma risk among kids. And at high levels, the compounds can spur irritation of the eyes and respiratory tract, headaches and dizziness, Fineman said.

"Products marketed as 'all-natural' or even those that are unscented canemit hazardous chemicals," Fineman said in the statement. "The safest option is to avoid exposure to pollutants that air fresheners emit."

MyHealthNewsDaily reported that a 2009 study shows that almost one third of people who have asthma also arehyper-sensitive to chemicals.

Alcoholic drinks and petscan also be allergy triggers for some people, theChicago Sun-Timesreported.

More than50 million people in the United States have an allergy, with triggers ranging from pollen to dust mites to food, according to the ACAAI. Asthma and other allergic diseases are the fifth most common chronic disease in both adults and children.

To find out the30 worst U.S. cities for allergies, take a look at this ranking from research lab Quest Diagnostics:

Phoenix

Ragweed Sensitization Rate: 29.3  <em>Source: <a href="http://www.questdiagnostics.com/home/physicians/health-trends/allergies" target="_blank">Quest Diagnostics</a>.</em>
Ragweed Sensitization Rate: 29.3 Source: Quest Diagnostics.

Las Vegas

Ragweed Sensitization Rate: 25.7
Ragweed Sensitization Rate: 25.7

Kansas City

Ragweed Sensitization Rate: 24.1
Ragweed Sensitization Rate: 24.1

Riverside-San Bernardino

Ragweed Sensitization Rate: 24.1
Ragweed Sensitization Rate: 24.1

Dallas

Ragweed Sensitization Rate: 23.6
Ragweed Sensitization Rate: 23.6

Chicago

Ragweed Sensitization Rate: 23.1
Ragweed Sensitization Rate: 23.1

Sacramento

Ragweed Sensitization Rate: 22.9
Ragweed Sensitization Rate: 22.9

Philadelphia

Ragweed Sensitization Rate: 22.6
Ragweed Sensitization Rate: 22.6

Denver

Ragweed Sensitization Rate: 22.3
Ragweed Sensitization Rate: 22.3

Washington, D.C.

Ragweed Sensitization Rate: 21.7
Ragweed Sensitization Rate: 21.7

Minneapolis/St. Paul

Ragweed Sensitization Rate: 21.7
Ragweed Sensitization Rate: 21.7

New York

Ragweed Sensitization Rate: 21.2
Ragweed Sensitization Rate: 21.2

Cincinnati

Ragweed Sensitization Rate: 21.1
Ragweed Sensitization Rate: 21.1

Baltimore

Ragweed Sensitization Rate: 20.5
Ragweed Sensitization Rate: 20.5

Cleveland

Ragweed Sensitization Rate: 20.3
Ragweed Sensitization Rate: 20.3

St. Louis

Ragweed Sensitization Rate: 19.9
Ragweed Sensitization Rate: 19.9

Detroit

Ragweed Sensitization Rate: 19.9
Ragweed Sensitization Rate: 19.9

Atlanta

Ragweed Sensitization Rate: 19.4
Ragweed Sensitization Rate: 19.4

Boston

Ragweed Sensitization Rate: 18.1
Ragweed Sensitization Rate: 18.1

Pittsburgh

Ragweed Sensitization Rate: 17
Ragweed Sensitization Rate: 17

Orlando

Ragweed Sensitization Rate: 17.6
Ragweed Sensitization Rate: 17.6

Los Angeles

Ragweed Sensitization Rate: 17.4
Ragweed Sensitization Rate: 17.4

San Antonio

Ragweed Sensitization Rate: 17.4
Ragweed Sensitization Rate: 17.4

Houston

Ragweed Sensitization Rate: 16.6
Ragweed Sensitization Rate: 16.6

Seattle

Ragweed Sensitization Rate: 15.6
Ragweed Sensitization Rate: 15.6

San Diego

Ragweed Sensitization Rate: 15
Ragweed Sensitization Rate: 15

Tampa

Ragweed Sensitization Rate: 14.3
Ragweed Sensitization Rate: 14.3

Portland

Ragweed Sensitization Rate: 14.2
Ragweed Sensitization Rate: 14.2

San Francisco

Ragweed Sensitization Rate: 11.4
Ragweed Sensitization Rate: 11.4

Miami

Ragweed Sensitization Rate: 10.8
Ragweed Sensitization Rate: 10.8

This article originally appeared on HuffPost.