By John Musenze
Photos by WHO
A new study in South Africa is set to track how environmental factors such as air pollution, weather, and pollen are driving asthma in children, in what researchers said could pave the way for early warning systems and better prevention strategies.
The study, known as the South Africa Climate, Air Emissions and Respiratory Health Early Sensing (SA CARES) project, will follow 300 children with asthma across multiple communities, combining detailed health monitoring with real-time environmental data.
Researchers at the Desmond Tutu Health Foundation in Cape Town hope the findings will help explain why asthma attacks spike at certain times and how to predict them.
The research comes at a time when chronic respiratory diseases are gaining attention globally but remain largely neglected in public health debates.
According to the World Health Organization (WHO), these diseases killed nearly 3.5 million people in 2024, placing a heavy burden on health systems and economies.
In Africa, the impact is compounded by rapid urbanisation, pollution, and limited access to diagnosis and treatment.
Asthma alone affects an estimated 10 to 15 percent of South Africa’s population, while up to 60 percent suffer from allergic rhinitis, conditions that often go undiagnosed or poorly managed. Across the continent, chronic respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD), are rising steadily.
COPD is now the fourth leading cause of death globally, with nearly 90 percent of deaths among people under 70 occurring in low- and middle-income countries, including many in Africa.
Despite this growing burden, experts said the environmental drivers of respiratory disease remain poorly understood, particularly in African settings.
The SA CARES study aims to change that by taking an unusually detailed approach. Led by researchers at the University of Cape Town Lung Institute, the project will monitor children aged between six and 15 over a year, tracking both their health and the environments they live in.
“We want to understand how climate change is affecting the environment, and in turn how that is affecting asthma in children,” said Caryn Upton, the clinical project lead of the study, who told journalists during a WHO media workshop supported by Pace University in Cape Town from March 2nd -6th.
At the heart of the research is what scientists call a “sentinel” model. The children enrolled in the study will act as early indicators of wider community trends. By closely monitoring when their symptoms worsen, researchers hope to detect patterns that indicate broader spikes in respiratory illness, such as increases in hospital visits or medication use.
The study will collect data at multiple levels. Weather conditions such as temperature, humidity, and rainfall will be tracked alongside air quality indicators like particulate matter and gases. At the same time, biological particles in the air, including pollen, fungi, and other allergens, will also be measured.
“Pollen doesn’t exist in a silo, and neither does air pollution or weather. All of these factors interact, and we need to understand how they combine to affect health.” Upton explained.
Previous research has shown that climate change can intensify these interactions. Rising temperatures can increase pollen production and extend pollen seasons, while pollution can make pollen more potent. Rainfall may temporarily reduce airborne pollen but also promotes the growth of mould, another key asthma trigger.
In some cases, these interactions can lead to extreme events. One of the most striking examples is thunderstorm asthma, where a combination of high pollen levels, humidity, and storm conditions can trigger mass asthma attacks. A 2016 event in Melbourne, Australia, led to more than 3,000 emergency visits and several deaths within days.
South Africa has already seen how environmental changes can influence pollen levels. During a severe drought in Cape Town between 2017 and 2018, pollen levels dropped significantly, only to surge dramatically after heavy rains returned, producing one of the most intense pollen seasons in a decade.
The new study will build on data from the South African Pollen Monitoring Network, which has been tracking airborne allergens across multiple cities since 2019. These data have already helped create pollen calendars that show when certain allergens peak during the year.
According to Upton, participating children will undergo intensive monitoring at home, school, and community levels. For two-week periods during the study, researchers will install air quality sensors in their homes, measure gases and particulate matter, and even collect dust samples from bedding to analyse exposure to allergens like house dust mites.
The children themselves will perform daily lung function tests and record their symptoms twice a day, providing a detailed picture of how their condition changes over time.
Researchers will also examine social and environmental factors such as housing conditions, proximity to roads or vegetation, and differences between urban and rural settings. Urban areas, for example, tend to have higher levels of traffic-related pollution, while rural areas may expose children to more pollen and agricultural dust.
By combining all this data, the team hopes to identify which environmental factors, and which combinations of factors, are most strongly linked to asthma flare-ups.
“If the data supports it, we could develop early warning systems. That could mean alerting hospitals to prepare for increased admissions, or sending messages to patients advising them to take precautions.” Upton said.
Experts said this kind of predictive approach could be transformative, particularly in low-resource settings where health systems are often overstretched.
José Luis Castro, the World Health Organization’s Special Envoy for Chronic Respiratory Diseases, warned that lung diseases remain largely invisible despite their massive toll. Beyond health impacts, they reduce productivity, increase healthcare costs, and deepen social inequalities.
“One of the main challenges is that these diseases have remained largely invisible both to the public and to policymakers. When diseases are invisible in public discourse, they are also invisible in decisions about funding for diagnostics and treatment. We have the tools to prevent an entire generation from developing these diseases. The question is whether we will use them,” said José Luis Castro, WHO director-general special envoy for chronic respiratory disease