Asthma and Cities: Which Cities Rank Best?
You may already know the worst cities for asthma. What about the best?
'Best' Cities for Asthma? continued...
Weather Conditions. Many cities that ranked well for people with asthma have fairly mild climates, like San Francisco and Seattle. Asthma experts say that extreme temperatures are a common nonallergic asthma trigger.
"When the air gets really cold, it can almost shock the lungs and cause a bronchospasm that narrows the airways," says Bernstein. Shifts in barometric pressure are another common asthma trigger, he says.
That said, the potential benefit of living in a mild climate depends entirely on your asthma triggers. Some people with asthma do well when they move away from the cold winters of Minnesota to hot, arid climate of Arizona. For others, it doesn't make much of a difference.
While some coastal towns ranked well on the AAFA's list of asthma cities, their humidity could be a problem for many people with asthma. Humidity is an irritant that can trigger asthma symptoms. Also, humid environments encourage allergens like mold and dust mites.
"Cape Coral, Fla. ranked [best] on our Asthma Capitals list this year," says Waldron. "But if mold is a trigger for you, it might not be so great."
Pollen Count. Pollens are among the most common allergic triggers for people with asthma. The types of pollen and the season vary from region to region.
"In the spring, some of the toughest cities are in the southeast, because that's when tree pollen from oak, maple, and elm is worst," says Waldron. "Then in the fall, the ragweed in the northeastern cities becomes a real problem."
Of course, it all depends on the type of pollen. If you live in an area with a high pollen count but aren't allergic to those particular pollens, you won't have a problem.
Pollution. "It's no surprise to anyone that cities have a lot of pollution," says Charlot. "In a city, you've got more cars on the road, more businesses, and more factories putting pollutants into the air." Since pollutants themselves can be irritants, they can have a big effect on a person's asthma symptoms.
What you might not realize is that pollution levels can also indirectly increase pollen levels. How? Carbon dioxide is a waste product produced by combustion; it's also a gas that plants need to grow.
"Studies have shown that in urban areas with a lot of pollution, the high carbon dioxide levels encourage plant growth," says Bernstein. "That increases the pollen levels."
Other Allergens. Keep in mind that cities in general are likely to have pests -- like cockroaches, mice, and rats -- all of which can trigger allergies and asthma attacks. They're often most problematic in poorer urban neighborhoods.
Smoking Ordinances. When evaluating a particular city's effect on asthma, it's not only about pollen counts and weather. Charlot says that smoking laws -- banning smoking in workplaces and restaurants, for instance -- may be having a real impact on asthma symptoms.
"Some studies have found that in cities that enact smoking legislation, there's a decrease in ER visits for asthma emergencies," Charlot tells WebMD.