Chiang Mai, Thailand · Two smoke seasons · From classroom PM2.5 observation to evidence, authority, and verified consequence.
A guided interpretation of AirGradient's published comparison of classroom air purifiers and positive-pressure systems. This is not an independent verification of the underlying measurements.
PRE-EXAMINATION · BASELINE NOT FROZEN · NO AIRGRADIENT OR SCHOOL ENDORSEMENT. Illustrative teaching graphics are not original instrument records. TA14 has not issued a performance certification or a formal disposition.
Start with the children, not the equipment. Smoke outside is a real environmental concern, but an individual child's exposure cannot be calculated from this illustration.
Children experience the air that actually exists in the classroom.
AFTER THE IMAGE · THE NEXT QUESTION
What specific conditions must be observed in occupied classrooms before an intervention can be justified?
TEACHING IMAGE 02 OF 08
From Observation to Evidence
BEFORE THE IMAGE · WHAT TO LOOK FOR
A sensor number alone is not a complete evidence record. We need units, timestamp, instrument, location, methods, and operating context.
A PM2.5 reading becomes useful evidence only with attributable context.
AFTER THE IMAGE · THE NEXT QUESTION
Were both technologies observed during comparable school hours and under documented conditions?
TEACHING IMAGE 03 OF 08
Two Approaches, Different Results
BEFORE THE IMAGE · WHAT TO LOOK FOR
In 2025 the reported outdoor, purifier, and included PPS means were 58.7, 24.2, and 3.4 micrograms per cubic meter. In 2026 they were 87.8, 17.4, and 5.0. These are observed group averages, not proof of a universal effect.
The reported classroom comparisons favor positive-pressure systems among included installations.
AFTER THE IMAGE · THE NEXT QUESTION
How does the exclusion of eight malfunctioning or unmaintained PPS systems change the interpretation?
TEACHING IMAGE 04 OF 08
The Exceptions
BEFORE THE IMAGE · WHAT TO LOOK FOR
The eight excluded installations are a crucial operational limitation. Specific failure scenarios drawn in the teaching image are illustrative, not verified diagnoses of those eight systems.
Eight malfunctioning or non-maintained installations were excluded from the performance comparison; their individual failure causes are not established here.
AFTER THE IMAGE · THE NEXT QUESTION
What maintenance, fault history, and exclusion reasons would an independent examiner need?
TEACHING IMAGE 05 OF 08
Traceable Air Quality Evidence Record
BEFORE THE IMAGE · WHAT TO LOOK FOR
An evidence record should preserve raw values and transformations separately. Example record IDs and sample sensor values shown in this teaching image are illustrations.
Preserve raw readings, timestamps, instruments, maintenance context, methods, and limitations.
AFTER THE IMAGE · THE NEXT QUESTION
Could an independent reviewer reconstruct the comparison and identify missing records?
TEACHING IMAGE 06 OF 08
Evidence Fit for the Decision
BEFORE THE IMAGE · WHAT TO LOOK FOR
Evidence adequate for a published observational comparison may not be adequate to authorize a particular school's construction or procurement decision.
Evidence sufficient for a research comparison may not suffice for a specific school investment.
AFTER THE IMAGE · THE NEXT QUESTION
What local evidence, constraints, professional judgment, and authority remain unestablished?
TEACHING IMAGE 07 OF 08
From Evidence to Authorized Action
BEFORE THE IMAGE · WHAT TO LOOK FOR
Research can inform a recommendation. Engineers can evaluate options. Only actors with applicable authority and standing may approve the specific consequential action.
An intervention requires applicable authority, established standing, and a bounded commitment.
AFTER THE IMAGE · THE NEXT QUESTION
Who authorizes this exact scope, and when must the authorization be revalidated?
TEACHING IMAGE 08 OF 08
From Authorization to Real-World Impact
BEFORE THE IMAGE · WHAT TO LOOK FOR
After an authorized intervention, preserve what was installed, tested, accepted, and measured. The illustration's dashboard values are examples, not original study readings. Health and attendance improvements would require separate evidence.
Verify what was executed, what changed, and what remains uncertain.
AFTER THE IMAGE · THE NEXT QUESTION
What outcome was actually measured, what remained uncertain, and what must be monitored next?
Reported findings and boundaries
The study reported mean classroom PM2.5 of 24.2 versus 3.4 µg/m³ in 2025, and 17.4 versus 5.0 µg/m³ in 2026, for purifier and positive-pressure groups respectively during school opening hours. These are comparisons among included installations, not randomized treatment effects. Eight malfunctioning or non-maintained positive-pressure installations were excluded. Their exclusions remain material to generalizability and operational decision-making.
Apply the governance principles to three hypothetical cases relevant to school air and building operations. Choose a determination, then examine the reasoning. These cases teach the distinction between Admissible Evidence, Applicable Authority, and Established Standing; they do not issue real-world authorization.
CASE 01
Classroom ventilation versus outdoor particles
A controller recommends increasing outdoor air based on indoor CO₂, but outdoor particulate conditions have materially changed since the recommendation. No new binding assessment exists. What is supported?
CASE 02
Unverified school operator
The evidence is complete, but the individual attempting to issue a district-wide building command has no established standing in that capacity. What is supported?
CASE 03
District-level safety exception
A proposed school intervention triggers a district safety approval that the site operator cannot issue. What is supported?
Independent educational examples only. The questions are hypothetical and do not assess a real institution, building, person, or operating system. Actual governance determinations require case-specific evidence, applicable authority, established standing, and bounded review.