Climate risks
Assessing wildfire smoke exposure risk for indoor spaces and designing building retrofits to improve air quality protection.
This piece explains practical methods for evaluating indoor exposure to wildfire smoke, and outlines retrofit strategies that strengthen air barriers, filtration, and ventilation, protecting occupants during smoky seasons.
Published by
Matthew Clark
August 03, 2025 - 3 min Read
As communities increasingly contend with wildfire smoke, indoor air quality becomes a critical concern for public health and productivity. Understanding exposure involves mapping smoke ingress paths, measuring pollutant concentrations, and evaluating occupancy patterns. Key pollutants include fine particulate matter and a range of gases that penetrate typical building enclosures. Occupants can be exposed even when windows are closed, particularly if filters are inadequate or mechanical systems draw air from contaminated exterior zones. By combining ambient air monitoring with building diagnostics, stakeholders can quantify risk, identify vulnerable spaces, and prioritize interventions that yield the greatest protection with reasonable costs and disruption.
A robust assessment starts with characterizing local wildfire behavior and prevailing wind patterns, then translating those dynamics into building-specific risk profiles. Consider how stack effects, system pressures, and filtration efficiency influence pollutant entry. Evaluate envelope performance, including cracks, doors, and shared ventilation ducts, as potential ingress routes. Indoor sources such as cooking and candles can compound outdoor exposures during smoky periods, so a holistic view is essential. Time-of-day usage, occupancy density, and the presence of sensitive populations—children, elderly, or those with respiratory conditions—shape the severity of indoor exposure and guide tailored protective measures that fit real-world routines.
Strengthening filtration and air handling for ongoing resilience.
Retrofit planning should begin with a prioritized list of protective measures that balance effectiveness, cost, and disruption. Upgrading filtration to higher efficiency models, such as MERV 13 or beyond, can significantly reduce particulate ingress while maintaining airflow comfort. Sealing obvious air leaks around windows, doors, and mechanical penetrations minimizes uncontrolled exchange with polluted outdoor air. Enhancing a building’s pressurization strategy—favoring cleaner zones and differential pressures—helps shield occupied spaces from contaminated inflows during peak smoke events. It is important to sequence upgrades so that essential systems remain functional throughout retrofit work, preserving safety and operations.
A practical retrofit plan also considers filtration maintenance, energy implications, and user comfort. Implementing smart or demand-controlled ventilation can optimize outdoor air intake in line with occupancy and air quality readings, reducing unnecessary emissions. Portable or fixed air cleaners with appropriately sized units offer flexibility for high-risk rooms or temporary closures. Material choices matter too: durable, washable filters and easily serviceable components reduce long-term maintenance burdens. Finally, communicate plans clearly to occupants, outlining expected disruptions, maintenance schedules, and the rationale behind each measure to foster cooperation and trust during the retrofit process.
Creating safer spaces through enclosure and source control measures.
Upgrading filtration is often the most effective single intervention for wildfire smoke resilience. Selecting filters with validated performance ratings and verifying compatibility with existing equipment ensures improvements do not cause unintended operational issues. In environments with variable occupancy, consider modular approaches that allow different zones to receive targeted filtration. Regular maintenance routines—filter changes, coil cleaning, and duct inspections—keep systems functioning at peak efficiency. To avoid pressure imbalances, engineers should monitor static pressure and adjust fan speeds as filters become denser. This approach reduces the risk of contaminant infiltration while preserving thermal comfort and energy use.
In addition to filtration, improving air handling strategy can dramatically cut exposure. Positive or neutral pressure in sensitive spaces, achieved with dedicated exhaust management and controlled fresh air intake, helps prevent contaminated air from migrating into occupied rooms. Where possible, separate air handling for high-risk areas from general spaces reduces cross-contamination. Smart controls can align ventilation rates with outdoor smoke intensity, improving energy performance without sacrificing protection. Documentation of system configurations, maintenance logs, and performance targets enables facilities teams to respond quickly when smoky conditions persist, maintaining safe conditions for occupants.
Monitoring and response plans for real-time air quality management.
Enclosure improvements focus on reducing smoke penetration at the building envelope. Sealants, weatherstripping, and gasket upgrades around doors and operable windows limit unintended air leakage. Consider installing dedicated makeup air systems that pull fresh air from low-pollution zones or filtered exterior environments, if feasible within budget and design constraints. Weatherizing exterior penetrations and coordinating with roof or façade upgrades ensures long-lasting performance. Localized measures, such as sealing junctions around utility lines and penetrations, can dramatically cut the volume of contaminated air entering internal spaces during wildfire events.
Source control complements enclosure work by addressing internal emissions and behavior. Encouraging reduced use of combustion-based appliances during smoke events minimizes additional pollutants. Public guidance can help occupants avoid burning candles, frying foods, or operating fireplaces when outdoor air quality is poor. Strategically relocating activities that emit odors or particles away from occupied areas lowers exposure risk. In office and educational settings, scheduling high-emission tasks during cleaner periods helps protect vulnerable individuals. This holistic approach acknowledges that indoor air quality results from both external influences and human choices inside the building.
Integrating policies, equity, and long-term planning for climate resilience.
Real-time monitoring becomes a cornerstone of effective indoor air protection. Deploying sensors in representative zones provides continuous snapshots of PM2.5, VOCs, CO2, and humidity levels helps detect shifts in air quality. Integrating sensor data with building management systems enables automated responses, such as increasing filtration or adjusting ventilation when pollutant levels rise. Establish clear action thresholds that trigger predefined protocols, minimizing ad hoc decisions during emergencies. Regular sensor calibration and maintenance are essential to avoid erroneous readings that could undermine safety. A well-designed monitoring framework supports informed occupancy decisions and rapid response during smoky conditions.
Communication and occupant engagement are critical when wildfire smoke intensifies. Transparent alerts about air quality, expected durations, and recommended protective actions empower individuals to protect themselves. Providing guidance on when to stay indoors, how to use portable air cleaners, and where to obtain clean air can reduce anxiety and confusion. Educational materials should be accessible to diverse audiences, including non-native speakers and children. When facilities teams communicate proactively, they build trust, encourage compliance with protective measures, and reduce the risk of exposure across shared spaces.
Equity considerations must be central to retrofit programs, ensuring that all occupants benefit from improved air quality. Cost barriers should be mitigated through scalable solutions, incentives, and transparent budgeting that prioritizes high-risk populations and public buildings. Community engagement helps align retrofit choices with local needs, while data on outbreak patterns and air quality trends informs prioritization. Long-term resilience requires updating building codes, design standards, and maintenance practices to reflect evolving wildfire regimes. By embedding air quality protection into policy, communities can withstand smoke events with fewer health consequences and fewer interruptions to daily life.
Finally, a forward-looking approach combines retrofit planning with adaptive design. Buildings that anticipate worsening smoke episodes can incorporate flexible filtration systems, modular enclosures, and resilient ventilation strategies that accommodate future upgrades. Regular performance reviews, lessons learned from past fires, and ongoing training for facilities staff keep protection current. Embracing an integrated system—spanning envelope, filtration, monitoring, and occupant behavior—creates a durable shield against wildfire smoke and supports healthier indoor environments for years to come.
