BETHLEHEM, Pa. — Each year, Dr. Robert Zemble’s patients ask him if it’s the worst allergy season in the Lehigh Valley.
- Near drought conditions in the Lehigh Valley have exacerbated seasonal allergies for many residents
- Mosquito populations so far seem unaffected
- There's no significant chance for rain through the weekend
The problem with that question, he said, is that every year here can be a struggle for residents with allergies.
“We just consistently have very high pollen levels during tree and grass season, and we have these periods of time where there's no rain and there's very high levels every year,” said Zemble, who serves as the division chief of allergy at Lehigh Valley Health Network. “It just happens to be a longer stretch this year where there are dry conditions.
“Essentially, we are a spring destination for pollen sufferers.”
The bone-dry conditions in the Lehigh Valley certainly aren’t helping, and the impact is wider than only those allergy sufferers. An extended stretch of dry weather has led to drought conditions across the region and beyond, helping to fuel brush fires. However, mosquito populations, dependent on water for the beginning of their life cycle, are still measuring in normal ranges.
Is the Lehigh Valley in a drought?
Officials at the U.S. Drought Monitor on Thursday released a map showing the majority of Pennsylvania, including most of the Lehigh Valley, has moved into a drought.
In a map released Thursday, nearly the entire state of Pennsylvania was designated as in "moderate drought" or “abnormally dry” by the U.S. Drought Monitor. The latter status is a precursor to drought and is likely to worsen over the next few weeks.
However, the state Department of Environmental Protection lists Pennsylvania as “normal” for its drought status.
LehighValleyNews.com has reached out to DEP officials to understand why the U.S. Drought Monitor and the DEP’s drought status would differ.
Last month was the second-driest May ever with under a quarter-inch of rain recorded. It ranked behind only the 0.09 inches recorded in May 1964.
Does less rain mean fewer mosquitoes?
One of the intuitive benefits of a dry spring and early summer could be a decrease in mosquito populations, but environmental officials and researchers said that, so far, it’s just not the case.
"We haven’t seen any noticeable differences in mosquito populations so far in 2023. The population surveys are finding about as many mosquitoes as usual at this time of year; that could obviously change if the weather stays as dry as it has been.”Neil Shader, spokesperson for the Pennsylvania Department of Environmental Protection
“We haven’t seen any noticeable differences in mosquito populations so far in 2023,” said Neil Shader, a DEP spokesperson. “The population surveys are finding about as many mosquitoes as usual at this time of year; that could obviously change if the weather stays as dry as it has been.”
Mosquitos live in water for the first one to two weeks of their life cycle, said Muhlenberg College biology professor Marten Edwards. There are about 176 different species of mosquito that live in the U.S., with over 62 mosquito species in Pennsylvania alone.
“Mosquitoes have their place in the food chain and along with other insects are food sources for birds and fish,” Edwards said. “The most bothersome mosquitoes, like the Tiger Mosquito, are introduced pests that are taking advantage of the water sources that we generously provide for them.
“Our dry summer is making life harder for them — and that's just fine with me.”
But just because it’s harder for mosquitoes to thrive in dry, hot weather doesn’t mean that they won't adapt, finding water where they can.
Kevin Frederick, district manager for the Lehigh County Conservation District, said “while dry conditions may put a damper on the mosquito population in time, we are still seeing our usual population numbers.”
The mosquitos responsible for transmitting West Nile virus love living and breeding around people and their homes, Frederick said.
“Containers such as buckets, tires, saucers under potted plants, bird baths, kiddie pools and clogged rain gutters found throughout neighborhoods are known to be prolific breeding habitats — even in dry seasons,” he said. “Just because the rain isn’t providing the mosquitoes with regular puddles to breed in, doesn’t mean that they aren’t doing everything they can to continue to reproduce.”
‘Dry, windy days are the worst days for pollen’
The allergy season starts in the spring and can run through the fall, Zemble said. Right now, the Valley is in the midst of the peak grass allergy season.
“Around here, peak tree season is March, April, May,” he said. “Peak grass season is May and June. By July 4, I give patients the date as the unofficial end of spring allergy season and there's still some grass, but it's much lower than the peak kind of spring season.
“And then mid-August ragweed picks up for the fall season, and then you also get mold in fall season as well.”
The two least allergenic months, he noted, are February and July.
“The pollen that's sitting on all the cars – that's a nice way of knowing there's a lot of pollen out, but that's not really what's bothering people as much as the pollen that you can't see that you're just breathing in because it's just getting transported through the air,” Zemble explained. “We always say dry, windy days are the worst days for pollen.
“So, if we have weeks straight of dry, windy days, people aren't going to get a reprieve from it being washed out of the air.”
While Zemble said he doesn’t want his patients to limit their life and activities because of their allergies, it’s important to keep “the outside outside.” He uses a three pronged approach to allergic disease: avoidance measures, medications and, for certain people, desensitizing themselves.
“You're going to be having this exposure when you're outside but keep the windows shut at home, in the car, keep the air on with the filters running so you're not breathing in the pollen when you're in a safe space,” he said. “ … And then the other aspect is, well, if you treat your symptoms before you're miserable, you're going to become less miserable.”
