People living and working close to the ongoing blaze in Deptford have been urged to avoid the smoke as the fire continues to burn.
Public Health England says the smoke from the blaze consists of a mixture of gases, liquid droplets and solid particles.
Some of the substances present in smoke can irritate the lining of the air passages - nose, throat and lungs - the skin and the eyes.
Symptoms may include coughing and wheezing, sore throat, feeling short of breath, runny nose or eyes or chest pain.
In general, exposure to smoke is more likely to affect people who have existing breathing problems, lung or heart conditions such as asthma, bronchitis, chronic pulmonary disease or heart disease.
These individuals should avoid strenuous physical activity in areas affected by smoke.
The very young and very old, smokers and people with flu or flu-like illnesses may also be at greater risk after exposure to smoke from fires.
People who are generally fit and well are unlikely to experience long-term health problems from temporary exposure to smoke from a fire.
To minimise your exposure, shelter as much as possible by limiting the amount of time you spend outside in the smoke.
Reduce physical exertion in areas affected by smoke especially if you experience symptoms such as cough or sore throat.
People with asthma who may be in the vicinity of the fire should carry their inhaler.
If symptoms persist seek medical advice by calling NHS 111 or by contacting your General Practitioner.
If a medical consultant is already treating an existing health condition, discuss your concerns and symptoms with them.
In the case of an emergency call 999.
Residents in areas affected by the smoke should stay indoors, keep their doors and windows closed and follow @PHE_NorthEast for the latest health advice and information.
During the day, if smoke is visible outside, please stay indoors, keep windows and doors closed, consider turning off air conditioning and keep air vents closed.
Businesses may wish to consider the same advice.
Motorists who have to travel through the smoke should keep windows closed, turn off air conditioning and keep their air vents closed.
The majority of people are unlikely to experience any health effects following exposure to smoke from a fire, however because any smoke is an irritant, it can make people’s eyes and throat sore.
As the fire service continues to fight the blaze, the Salvation Army's North East England emergency mobile response team has been on hand to support the crews, offering them food and drink as they take their breaks.
The volunteers have included ministers from the Sunderland Citadel, Monkwearmouth and Millfield Salvation Army churches as well as South Shields Salvation Army, and managers from Swan Lodge Lifehouse - accommodation for people experiencing homelessness - and the Southwick Community Project.
All shifts by the volunteers were provided in addition to their full-time work and ministry in the city.
Each day, the staff and residents of Swan Lodge have prepared up to 500 sandwiches to keep up the supplies.