Flooding frequently results in respiratory health problems: These actions can be beneficial.

Health risks may arise from mould growth and pollutants left behind after significant storms.

One consequence of climate change is significant flooding occurrences, which are exacerbated by heavy rainfall and sea level rise. Injuries received when escaping or seeking shelter, hypothermia following exposure to cold waters without cover or heat, and drowning deaths are among the immediate harms frequently caused by rushing water into structures.
However, flooding continues to have an impact on communities in both obvious and hidden ways long after news trucks have left and the public’s focus has shifted. An increased risk of respiratory health issues, such as asthma and allergic reactions, is one of the less obvious dangers. Thankfully, there are things you may do to prevent or lessen flooding or to lower the hazards to your respiratory health if it happens.

How might respiratory health problems be brought on by flooding?

Flooding can introduce water into buildings that is tainted with sewage, heavy metals, pesticides, biotoxins, toxic compounds, and water-borne infections. Some harmful pollutants are then still present in the dried sediments that are left over. This becomes microscopic dust that is released into the air when it is disturbed by routine activities like walking and cleaning. Everything that was there in that dried flood sediment — toxic compounds, metals, and biotoxins — is now in the air you breathe and could have an impact on your respiratory health.It is not necessary for buildings to be inundated during flooding in order to cause respiratory issues. After Hurricane Ida, water seeped into several of the properties we looked at through windows, ventilation ducts, and roofs; some of these homes were located more than 100 miles from the coastal areas that were hardest hit.

Additionally, mould growth can have an impact on health.
Mould, a fungus that grows on moist or decomposing organic materials, is another frequent threat. Indoor mould typically develops as a result of prolonged dampness and indicates a moisture or water issue. After a flood, damp materials within buildings provide the ideal environment for mould to grow quickly.
In every environment, mould can grow both indoors and outdoors. It spreads by producing microscopic spores that drift through the atmosphere and land in different places. Mould spores are present in all indoor spaces, but high concentrations have been associated with respiratory issues such sinusitis, asthma, and allergic rhinitis.Flooding therefore has an impact on respiratory health by raising the possibility of being exposed to elevated levels of mould spores both indoors and outdoors.
For instance, during Hurricane Katrina in 2005, the highest concentrations of mould spores were found indoors, while the average outdoor concentration in flooded areas was about twice that of non-flooded areas. Water damage enhanced mould growth and respiratory allergens, according to a research conducted in the UK in 2007 following Hurricane Katrina and the ensuing flooding.

Children are particularly susceptible to mold-related health issues. According to a study on the respiratory health of young children in 30 Canadian towns, households reporting mould or moisture had higher rates of all respiratory symptoms, including cough, bronchitis, asthma, and eye irritation. Other studies show that mould plays a role in children’s asthma development.

What steps can you take to guard against flooding’s negative health effects?

Following Hurricane Ida in 2021, our research in New Orleans, Louisiana, found similar characteristics that have a significant impact on respiratory health in both housing and flooding situations. Preliminary findings indicate that the age of a building’s roof and the number of precautions people took during hurricane-related flooding were two determining variables in whether significant indoor mould developed. Flood water height, the number of days spent at home throughout the week, and the number of precautions taken after Ida went through all had an impact on respiratory health.

Based on this and further research, we provide the following advice, some of which should be followed immediately after floods or heavy rains. Taking these and other precautions can help prevent flooding from hurricanes and other large storms, but they may not be able to completely prevent it.

Prior to the onset of heavy rainfall, flooding, or seasonal storms: Prevent water incursion

• To stop leaks, fix the roof, clean the gutters, and caulk the area around chimneys, vent pipes, and skylights. During hurricanes and storms, these are some of a building’s most susceptible parts.
• Clear out septic tanks and declutter drains.
• Build barriers and caulk gaps around windows and in outside walls to keep floodwater and heavy rain out.
• Install backflow valves on sewer lines to stop water from backing up into the house and a sump pump to remove water from the basement.

After significant rainstorms or flooding, act fast to minimise moisture and the growth of mould.

Limiting interaction with flood water is advised by the Environmental Protection Agency because it may include dangerous materials, such as raw sewage, and electrical dangers. Furthermore:

• Minimize your stay in flooded regions (particularly after hurricanes) or buildings until they are dry and safe.
• Check building for traces of water intrusion, dampness, and mold growth immediately after flooding.
• Drain floodwater and dispose of remaining sediment.
• Remove affected porous materials. If possible, dry them outdoors under sunlight.
• Increase the ventilation rate by leaving all windows and doors open, or use a large exhaust fan to dry out the building as fast as possible.
• Use dehumidifiers in damp spaces such as basements.
• Upgrade the air filters in your HVAC system to at least MERV 13, or use portable air cleaners with HEPA filters to reduce your exposure to airborne mold spores.
• Reduce the amount of time you spend in flooded areas or buildings until they are safe and dry, especially after hurricanes.
• Immediately following flooding, inspect the building for signs of mould growth, moisture incursion, and moisture.
• Empty floodwater and discard any leftover silt.
• Eliminate the impacted porous materials. Dry them outside in the sun if you can.
• Keep all windows and doors open to increase the ventilation rate, or install a powerful exhaust fan to quickly dry out the building.
• In damp areas like basements, use dehumidifiers.
• To lessen your exposure to mould spores in the air, replace the air filters in your HVAC system with at least MERV 13 filters or use portable air cleaners with HEPA filters.

How to respond if you observe the growth of mould

• To clean, put on rubber boots, gloves, and a well fitting N95 face mask.
• Anything that has come into touch with water should be cleaned and disinfected using soap, detergents, and/or antibacterial cleaning supplies.
• Mouldy goods should be disposed of in heavy-duty, sealed plastic bags.

You may significantly improve your respiratory health by taking precautions like these both before and after a significant storm.