HOUSTON -

Even though the yellow dust isn't coating everything, many more people are complaining about their allergies.

That is because we are still under tree allergy season, and it's what we don't see that is triggering our symptoms.

"Much of the visible pollen doesn't cause as many problems because they are on the larger size. The pollen that causes problems is microscopic," explained Dr. Eric Sandberg, an Allergy Specialist at Kelsey-Seybold Clinic. "What you can't see is what gets you."

Tree allergy season typically beings at the end of February. Relief for those who are allergic to trees finally starts to come as it tapers off in April and typically comes to an end by the start of May.

"It has been very busy this spring in all the allergy clinics," said Dr. Sandberg. "Pollen has been at very high levels. This season may be worse than others, but it is hard to quantify."

The City of Houston Pollen and Mold Department says we are experiencing the peak now. The number one allergen is Oak.

Good news is there has been some improvement.

Two weeks ago, the City of Houston reported a pollen count of nearly 4,000 grains per cubic meter of air.

At the top of the list was Oak making up just over 50 percent of the pollen count.

Wednesday's pollen report indicated a high allergy day for trees again, but this time the pollen count was just over 1,000 grains per cubic meter.

Still, Oak took the majority of that count at nearly 780 grains per cubic meter.

Other major tree pollen players this year are Pine and Cedar, according to the City of Houston.

Despite the tree pollen numbers going down, many folks are starting to be plagued by itchy, water eyes and runny noses.

That is because tree allergy season is coinciding with the peak of another allergen: grass.

Spring is peak season for grass allergies. There is another peak in the fall.

"Unlike tree allergy season, grass pollen is present year round in Southeast Texas 'despite what books say,'" expressed Dr. Sandberg.

So with tree pollen numbers going down, but still at high levels, allergy season seems to have gotten worse because of grass allergy season starting to ramp up.

"There is more grass pollen coming in April and May," said Dr. Sandberg.