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.

IAQ Professional vs. DIY Testing: When Should You Call an Expert?

October 27, 2026
Indoor air quality (IAQ) plays an important role in maintaining comfortable, healthy indoor environments. From airborne particles and moisture to ventilation problems and chemical pollutants, many factors can affect the air inside homes, offices, and commercial buildings. With affordable air quality monitors and DIY testing kits widely available, it's easier than ever to collect information about indoor conditions. But how reliable are these tools, and when is it time to consult an indoor air quality professional? Understanding the difference between DIY testing and professional IAQ investigations can help you make more informed decisions. What Is DIY Indoor Air Quality Testing? DIY indoor air quality testing involves using consumer-grade devices or testing kits to check certain indoor environmental conditions without hiring a professional. Common DIY tools include: Air quality monitors: Track indicators such as particulate matter (PM2.5), carbon dioxide (CO₂), temperature, and humidity, depending on the device. Mold testing kits: Collect samples that may be analyzed for mold, although results can be difficult to interpret. VOC monitors: Provide estimates or indicators of certain volatile organic compounds. Humidity meters: Help identify moisture conditions that may contribute to mold growth. Radon monitors: Measure radon gas (which is odorless, colorless and radioactive) concentrations indoors, either with short-term tests or long-term monitoring. These tools can be useful for observing trends and identifying conditions that may need further attention. However, they have limitations, particularly when it comes to accuracy, sampling methods, and interpreting results. What Does an IAQ Professional Do? An indoor air quality professional takes a more comprehensive approach to evaluating indoor environmental concerns. Rather than relying on a single reading or test result, a qualified professional considers multiple factors, including building history, ventilation, moisture conditions, occupant activities, and potential pollutant sources. A professional IAQ investigation may involve: Evaluating HVAC systems and ventilation performance. Inspecting for moisture intrusion and conditions that support microbial growth. Using appropriate instruments and sampling methods. Reviewing occupant concerns and patterns. Interpreting findings within the context of building conditions. Recommending practical next steps based on the available evidence. The goal is not simply to collect numbers. It is to understand what those numbers mean and how they relate to the building and its occupants. 

What Are VOCs and Where Do They Come From?

By Admin User • October 12, 2026
Indoor air can contain pollutants from sources we encounter every day. One important group is volatile organic compounds, or VOCs . What Are VOCs? VOCs are chemicals that can evaporate into the air from certain products and materials. Indoors, they may be released while a product is being used or, in some cases, continue to be emitted from materials and furnishings over time. Understanding potential VOC sources is an important part of evaluating and managing indoor air quality . Where Do VOCs Come From? VOCs can come from a wide variety of products and materials commonly found in homes, schools, offices, and other buildings, including: Paints, coatings, adhesives, and solvents Cleaning and disinfecting products Air fresheners, fragrances, and personal care products Furniture and cabinetry Flooring and carpets Building and renovation materials Stored fuels, chemicals, and hobby products Renovation activities may temporarily introduce additional VOC sources as new paints, flooring, adhesives, furnishings, and other materials are brought into a building. How Can VOC Exposure Be Reduced? Managing VOCs begins with understanding and controlling their sources. Building occupants and managers can consider increasing ventilation when appropriate, following manufacturer instructions, properly storing chemicals, and selecting lower-emitting products when practical. Because indoor environments vary, the presence of an odor does not necessarily tell you which VOCs are present or at what concentration. When Should You Consider an IAQ Professional? If there are persistent odors, occupant concerns, or questions about potential indoor pollutant sources, an indoor air quality professional can help evaluate the building, identify possible sources, and determine whether additional investigation or testing is appropriate. Learning where indoor pollutants come from is an important first step toward creating healthier indoor environments.  Looking for more information about indoor air quality? Visit IAQA for educational resources and information from the indoor air quality industry.

Can Fans Stir Up Dust and Trigger Allergies or Asthma?

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