For 4-year-old Jessica Holmes, the air itself can be toxic. It happens when she ventures outside her family's Northwest Washington home on days with high ozone levels, which are occurring in the D.C. region at a higher rate than normal this hot, drought-plagued summer.

"Children her age should be tearing around, but she'd be just worn-out all the time," said Dolores Holmes, recalling her daughter's worst asthma attacks. "She wouldn't be able to breathe. At times she'd be turning blue, and she couldn't tell me what was wrong.

"I didn't know how to help Jessica. I'd take her to the emergency room, just trying to keep her alive."

Thanks to an asthma program at Howard University Hospital, Holmes, 46, has learned ways to manage her daughter's condition. One recommendation: that Jessica not go outside on those "bad air days," which can aggravate asthma and other respiratory conditions.

But in Washington, as in much of the Northeast, this summer has seen the highest number of bad air days in the last four years. It's an aspect of the punishingly hot, humid, rainless weather that has been overshadowed by images of shriveled corn and brown lawns.

"We would consider this a tough ozone season, worse than last year," said Kristeen Gaffney, an environmental scientist in the U.S. Environmental Protection Agency's mid-Atlantic regional office.

The agency's New York branch has observed the same phenomenon. "We are on a pace to exceed last year, and it appears to be largely weather-driven," said Mary Mears, a spokeswoman for the EPA's New York-New Jersey office.

Asthma is a chronic respiratory disease in which the small airways in the lungs become inflamed, causing wheezing. The condition is made worse by ozone, a noxious atmospheric soup created when heat and sunlight cook up two main ingredients: volatile organic compounds and nitrous oxide.

This summer's miserable weather is essentially the perfect recipe for ozone: temperatures of about 90 degrees, stagnant air, high pressure and the lack of rain showers to wash away pollen and other air particles.

Physicians, day-care providers and the parents of children with asthma all say they are seeing ozone's effects.

"I'm very concerned about these high ozone levels, because we see here on a daily basis how they are impacting children and the elderly, especially among people who live in the inner city," said Floyd J. Malveaux, dean of the Howard University College of Medicine.

In many cases, staying inside offers no relief. Dust mites, pet dander and tobacco smoke aggravate respiratory problems, as does the lack of air conditioning. On Aug. 5, the region's most recent "Code Red" day, people were sitting on the doorsteps of one Washington housing complex literally gasping for breath, said Eleanor Thornton, a Howard University asthma counselor.

"Several people in the family had asthma, and they were all suffering," Thornton said. "They have no air conditioning, and there's no place they can go to get a break."

Asthma, which is rising worldwide, affects all races and economic groups, but low-income and minority populations are disproportionately affected, with higher rates of fatalities, hospital admissions and emergency room visits. Asthma rates in the United States have doubled over the past 15 years, with the rates rising most rapidly in children under 5 years old.

Day-care worker Katrina Scott doesn't need to see statistics. With 17 years in the business, she knows firsthand how asthma is afflicting more children than ever before.

"There was quite a string of days this summer where we had to keep the children inside because of the ozone rates," said Scott, assistant director of the New Horizon Child Development Center. One-third of the 170 children at the Forestville day-care center have respiratory problems, mostly asthma, that require the use of inhalers and other medical treatment.

The causes of asthma are complex, but air pollution is a well-known trigger. So far this summer, unhealthy ozone levels were reached on 34 days in the Washington area. Last year, the healthy level of ozone was exceeded on 30 days during the entire summer, which included September. In 1997, there were 24 unhealthy days and in 1996, there were 10.

Already this summer, the Washington area has had seven Code Red days, issued when ozone reaches its highest levels. Last year's full summer season yielded just six. Smog levels across the Northeast this summer have followed a similar pattern.

Despite the increased ozone levels of the last few years, government officials say there is no clear long-term trend in the nation's air quality. After consistent decline, ozone levels have fluctuated through the late 1980s and 1990s.

The recent uptick in ozone levels has meant a tough summer for people with asthma, especially children with no air conditioning at home.

"High pollen counts due to lack of rain are also contributing to [asthma] morbidity," said Ray Lucas, an attending physician in the emergency department at George Washington University Hospital.

Parents have sought relief wherever they can, keeping children inside or in air-conditioned public places. It's hard for children to be homebound when their friends are at the pool or in the park.

"The poor kids are definitely spending summer days inside," said Sandra Fusco-Walker, director of outreach services for the Fairfax-based Allergy and Asthma Network/ Mothers of Asthmatics, a nonprofit education group.

On bad air days, "I take mine to the mall. We do a lot of mall-walking," said Fusco Walker, of Philadelphia, who has three children with asthma.

At Scott's day-care center in Prince George's County, the children stay inside on high-ozone days. Whenever they go on field trips, the staff brings along the children's inhalers and medications. "We've all been trained on the use of these machines," she said. "We keep records of each child's medical condition and which medicines they're on."

A cottage industry has sprung up to service the growing ranks of asthma sufferers. Special bedding, hypoallergenic pillows, high-powered vacuum cleaners, lightweight nebulizers to administer inhaled medicine, educational materials--all are available in stores and on the Internet.

"It's a busy time of year for us," said Penny Carey, a respiratory therapist with Johns Hopkins Pediatrics at Home Inc. The program, established by the Johns Hopkins Health Systems and the Kennedy Krieger Institute, brings specialists into homes to help parents manage their child's illness, offering advice on how to anticipate attacks and reorganize households to better control the disease.

The program is one of many popping up in the region and across the country aimed at minimizing the number of times asthma attacks require an emergency room visit.

Dolores Holmes, whose daughter Jessica had her first attack as an infant, remembers those grim days.

"She used to be in the emergency room every two months," said Holmes, who works as a cook for a local church. Under guidance from Thornton, Holmes has gotten rid of old upholstered chairs, carpeting and bedding. These days, Jessica has had fewer serious asthma episodes, although Holmes still worries about the high ozone days.

"Any hot humid day when Jessica has to go out," she said, "I give her two puffs on the nebulizer first."

CAPTION: Delores Holmes helps her daughter Jessica, 4, use a nebulizer to control asthma. The summer heat and drought have exacerbated asthma symptoms, and staying indoors often brings little relief to sufferers.