THE BRONX - With a new ragweed season under way, experts say Bronx residents suffering from allergies and respiratory illnesses may be at higher risk than others.

?When you combine the ragweed pollen along with some of the Diesel exhaust in the environment, they actually can be about 1000 times more potent, and they can suffer a lot worse,? says Dr. Charles Shapiro, an allergist.

According to Shapiro, some 36 million Americans are allergic to the plant. Many people experience symptoms as early as the second week of August, and in some cases, they last until Thanksgiving.

That is when Mariana Peraita says her 3-year-old son, who suffers from asthma, experiences his worst attacks.

The symptoms of ragweed-related allergies range from itchy eyes to headaches and sinus infections. There is no known cure for the illness, but doctors can prescribe nasal sprays and allergy shots to help alleviate the symptoms. Over-the-counter allergy medicines are also available.

Shapiro says because nasal sprays can take several weeks to start working, he advices people to begin using them before the first symptoms appear.

Experts suggest that people who are prone to allergies avoid contact with pollen, keep windows closed, wash their hair after being outside and stay indoors during peak pollen times.