Indoor Air Quality Alert From Indiana to Nepal: Flooding and the Risks That Follow

Indoor Air Quality Alert

From Indiana to Nepal: Flooding and the Risks That Follow

Mid-August brought severe flooding to Indiana and surrounding states following several days of heavy rain, and power was out for nearly two weeks in some areas. Then, on August 26, 2026, catastrophic flash flooding struck areas along Nepal’s Himalayan border with Tibet, damaging communities, homes, roads, bridges, and other critical infrastructure. Search-and-rescue and relief operations remain underway, while authorities continue to monitor newly formed lakes and the possibility of additional flooding. Our thoughts and prayers go out to all those affected by these disasters and to their loved ones waiting for news.


The immediate priorities in any disaster are life safety, rescue, shelter, clean water, and essential services. But as communities begin the difficult process of returning to and repairing buildings, another concern can quickly emerge: indoor air quality.


Floodwater Does Not Leave When the Water Recedes

A building may look dry on the surface while moisture remains trapped inside walls, flooring, insulation, furniture, and other materials.


According to the U.S. Environmental Protection Agency (EPA), floodwater can introduce biological and chemical contaminants into buildings. Wet materials that remain damp can also create conditions where mold develops, sometimes within 24 to 48 hours.


After significant flooding, indoor environmental concerns may include:

  • Excess moisture and high humidity
  • Mold growth on wet building materials
  • Bacteria and other microorganisms carried by floodwater
  • Contaminated sediment and debris
  • Particles released during demolition and cleanup
  • Damaged or contaminated HVAC systems
  • Fumes from cleaning and restoration products
  • Carbon monoxide from improperly operated generators


These concerns can continue long after standing water disappears.


Drying Quickly Matters

One of the most important steps after a building is declared safe to enter is controlling moisture.


The CDC recommends cleaning and drying flooded buildings as quickly as possible, ideally within 24 to 48 hours when conditions allow. Materials such as carpeting, drywall, insulation, mattresses, upholstered furniture, and other porous items may be difficult to adequately clean and dry after extensive water exposure.


Simply making a building look dry does not necessarily mean the moisture problem has been resolved.


Hidden areas such as wall cavities, flooring systems, ceiling assemblies, crawlspaces, and HVAC components may require further evaluation.


Cleanup Can Affect the Air Too

Recovery activities can disturb mold, dust, sediment, and other contaminants and release them into the air.


EPA guidance recommends cleanup methods that minimize the amount of contamination becoming airborne. Appropriate personal protective equipment is also important. For mold cleanup following a disaster, EPA and CDC guidance recommends at least an N95 respirator, protective gloves, and goggles.


Ventilation can help with drying when appropriate, but conditions should be evaluated carefully. For example, EPA advises addressing visible mold before using fans or dehumidifiers that could potentially disturb contamination.

Do Not Forget the HVAC System

Heating, cooling, and ventilation systems should also be considered after flooding.


If floodwater, mud, or excessive moisture has reached HVAC equipment or ductwork, operating the system without evaluating its condition could potentially distribute contaminants throughout the building.


In heavily damaged buildings, a qualified professional may need to evaluate the HVAC system along with moisture levels, building materials, and other indoor environmental conditions before normal occupancy resumes.


Generator Safety Is Also an Indoor Air Quality Issue

Power outages often follow major floods, making portable generators essential for many communities.


However, generators produce carbon monoxide, an odorless and potentially deadly gas. EPA guidance states that portable generators should be operated outside and at least 20 feet away from buildings, not inside homes, garages, or other enclosed areas.


Recovery Includes the Indoor Environment

Nepal’s current emergency is first and foremost a humanitarian crisis. As rescue efforts transition into recovery and rebuilding, protecting indoor environments will become another important part of helping affected communities return safely to homes, schools, workplaces, healthcare facilities, and other buildings.


Flood recovery is not simply about removing water. It is about understanding what the water left behind.


Moisture management, proper drying, material removal, safe cleanup practices, HVAC evaluation, and appropriate professional assessment can all play an important role in reducing longer-term indoor environmental problems.


The Indoor Air Quality Association (IAQA) supports professionals around the world who work to identify and resolve indoor environmental challenges, including moisture, mold, water damage, ventilation concerns, and other air quality issues.


For additional indoor air quality resources or to locate an IAQ professional, visit IAQA.org and the IAQA Find-a-Pro Directory.

IAQA and Particles Plus Expand Strategic Partnership Through New Eight-Year Extension

By Sarah Fanger • July 22, 2026
The Indoor Air Quality Association (IAQA) is pleased to announce an eight-year extension of its sponsorship agreement with Particles Plus, building on the second year of the parties’ original two-year agreement. With this extension, Particles Plus will continue as IAQA’s exclusive Diamond Sponsor, reinforcing its commitment to supporting the association’s mission, initiatives, and long-term growth. In addition to its financial support, Particles Plus will provide strategic services and advisory guidance to assist IAQA as it strengthens programs, expands industry engagement, and advances its service to members and the broader indoor air quality community. “Particles Plus has already proven to be a valued partner to IAQA, and this extension reflects both the strength of our relationship and our shared confidence in the future,” said Stanley Yeskolski, President of IAQA. “As Diamond Sponsor, their continued support, strategic services, and advice will help IAQA grow, better serve our members, and further our mission across the indoor air quality industry.” “IAQA plays an essential role in supporting professionals who work every day to improve indoor environments,” said Adam Giandomenico, CEO of Particles Plus. “We are proud to extend this partnership for eight more years and to support IAQA not only through sponsorship, but also through strategic collaboration that helps the association strengthen its programs and expand its impact.” This renewed agreement reflects a shared commitment to advancing indoor air quality knowledge, supporting practitioners, and promoting healthier indoor environments through collaboration, education, and industry leadership. The original commitment began in 2025 and now will continue through 2035. 
Wildfire Smoke and Respiratory Protection

Wildfire Smoke and Respiratory Protection: Why N95 and KN95 Respirators Work Better Than Surgical Masks

July 18, 2026
Wildfire Smoke and Respiratory Protection: Choosing the Right Mask Wildfire smoke can affect communities located far beyond the fire itself. Wind can carry smoke across cities, states, and even national borders, as is happening currently across the Great Lakes and Northeastern US due to Canadian wildfires. The result is poor to hazardous air quality both outdoors and inside buildings. One of the main concerns in wildfire smoke is PM2.5. These particles are extremely small and can travel deep into the respiratory system. Exposure may irritate the eyes, nose, throat, and lungs. It can also worsen asthma, heart disease, and other existing health conditions. When outdoor air quality becomes unhealthy, reducing exposure should be the first priority. Staying indoors, keeping windows closed, using effective air filtration, and avoiding strenuous outdoor activity can all help. When going outside is necessary, wearing the right respiratory protection is important.

Wildfire Smoke Doesn't Stop at Your Front Door

July 17, 2026
When wildfire smoke rolls in, most people think about it as an outdoor problem: hazy skies, stinging eyes, the advice to stay inside. But "inside" isn't automatically safe. Smoke particles are small enough to slip through open windows and doors, gaps around trim and outlets, HVAC intakes, and even tiny leaks in the building envelope itself. Once they're in, they don't just disappear — they settle into carpets, upholstery, and ductwork, and keep affecting air quality long after the skies clear outside. Why Indoor Air Takes the Hit Too Wildfire smoke is loaded with fine particulate matter (PM2.5) — particles so small they bypass your body's natural filters and reach deep into the lungs. Unlike larger dust or pollen, these particles move easily through the small openings that exist in almost every building, including: Open or poorly sealed windows and doors Gaps around pipes, vents, and electrical penetrations HVAC systems pulling in outdoor air Cracks in the building envelope (siding, roofline, foundation) Without preparation, indoor PM2.5 levels can climb close to outdoor levels within hours of a smoke event starting. Preparing Before Smoke Arrives The best defense is proactive, not reactive. A few key steps make a real difference: 1. Seal the gaps. Weatherstripping, door sweeps, and caulking around penetrations reduce how much smoke can infiltrate. 2. Upgrade HVAC filtration. Use the highest MERV rated filter that your system is rated for; check with your HVAC company if you aren’t certain. A MERV 13 or higher filter (where the system allows) captures significantly more fine particulate than standard filters. 3. Have a portable air cleaner ready. HEPA-based units with adequate CADR(Clean Air Delivery Rate) ratings for the room size can be a fast, effective backstop, especially in bedrooms or common living areas. 4. Set HVAC systems to recirculate. Switching off fresh-air intake during active smoke events keeps outdoor smoke from being pulled directly inside. 5. Know your air quality resources. Track local AQI before smoke hits so you can act early instead of waiting until conditions are already unhealthy. The Takeaway Wildfire season is as much an indoor air quality issue as an outdoor one. Buildings are more porous than they look, and smoke will find its way in through the paths of least resistance. Preparing ahead of time — sealing gaps, upgrading filtration, and having a response plan — is what separates a minor inconvenience from a real health risk indoors.  Want more practical guidance on protecting indoor air during wildfire season? Explore IAQA's resources and connect with certified indoor air quality professionals at iaqa.org .