Bouts of breathlessness have been waking Rekha Advani (42) at 4 am almost everyday for the past week. For the severely asthmatic Chembur resident, this is a sign that winter has begun.

“I feel completely drained out after the attacks,” said Advani, an administrator in a Bandra nursing home.

Advani is not alone. The dip in temperature coupled with the morning smog has affected many asthma and chronic bronchitis patients.

Healthy individuals are also coming down with viral infections, colds and sore throats.

“I have been treating four to five such cases daily instead of the usual one or two,” said Dr A. G. Ballani, consultant physician at Lilavati Hospital.

The doctor had to get two asthma patients hospitalised in the past week.

Smog carries a high concentration of dust and aerosols, which easily enter the respiratory tract and cause infection.

“Exposure to smog is known to trigger breathlessness,” said Dr Amita Athavle, who heads the Environmental Pollution Research Centre at KEM Hospital in Parel. “Air pollution levels tend to rise with the onset of winter and peak after December,” she added.

Bombay Hospital physician Dr Ashish Tiwari said the ground-level ozone, which is a primary component of smog, damages the inner lining of lungs. People with asthma, bronchitis and chronic obstructive pulmonary disease — narrowing of lung’s airways — should consult their doctors, said Dr Athavle. “They may need to increase the dose of their medicines or take pneumonia vaccine.”

Advani has been using the nebuliser (device used to give reliever medicines to patients during an emergency) twice a day.

“My doctor has asked me to keep an oxygen cylinder handy so it can be used in case I get a severe attack and it takes too long to reach the hospital,” she added.