Smog and Allergies — How PIR Thermal Upgrades Cut Emissions | BOKKA
Smog triggers allergies — what Kraków doctors discovered and the role of thermal upgrades
A team at the Jagiellonian University Collegium Medicum has published the results of a three-year study that unambiguously confirms: PM2.5 suspended particulates contained in smog act as a strong allergen. Unlike classic allergies, smog exposure cannot be treated with desensitisation immunotherapy — only symptomatic care is available. This is another hard argument for cutting low-stack emissions at the source, and one of the most effective tools remains deep thermal upgrades of buildings using materials with a low thermal conductivity coefficient — primarily PIR insulation boards.
Jagiellonian University findings — PM2.5 triggers allergic reactions in 75% of healthy people
The study covered 30 volunteers, whose blood was sampled and exposed to PM2.5 suspended particulates isolated by a team from AGH from the atmosphere of Kraków. Participants were divided into two groups: people without diagnosed allergies and people allergic to birch pollen. All of them, however, complained of runny nose, breathlessness, cough and chronic respiratory complaints — which subsided during stays in regions with cleaner air.
Results:
- 75% of people without allergies showed an allergic reaction to PM2.5
- 83% of people allergic to birch additionally reacted to suspended particulates
- derivatives of carcinogenic benzo(a)pyrene were detected in the urine of test subjects
This is the first study in the world to demonstrate that suspended-particulate molecules constitute a standalone, strong allergen. Treatment? Strictly symptomatic — with no possibility of classic desensitisation.
Where smog in Polish cities comes from
The main source of PM2.5 and PM10 during the heating season is low-stack emission — burning solid fuels (coal, wood, sometimes waste) in obsolete domestic stoves. The higher a building’s heat demand, the more fuel goes into the boiler room and the more particulates reach the atmosphere. Every kilowatt-hour saved through effective insulation translates into a measurable reduction of emissions at the source.
That is why thermal upgrades of external envelopes — roofs, walls, floor slabs, ground-bearing floors — are among the cheapest anti-smog measures available to property owners, calculated per tonne of avoided CO₂ and per kilogram of avoided particulates.
WT 2021 — requirements that every thermal upgrade must meet
The Technical Conditions (WT 2021 — Polish Technical Conditions 2021), in force since 1 January 2021, tightened the maximum values of the U thermal transmittance coefficient for envelopes:
| Envelope | Umax per WT 2021 |
|---|---|
| Roof, flat roof | 0.15 W/m²K |
| External wall | 0.20 W/m²K |
| Floor slab over unheated basement/garage | 0.25 W/m²K |
| Ground-bearing floor | 0.30 W/m²K |
Reaching these values with traditional materials of λD ≈ 0.038–0.040 W/(m·K) requires considerable insulation thicknesses — often 20–25 cm on the roof and 18–20 cm on the wall. This is where PIR boards have the edge.
PIR boards — low lambda, smaller thickness, lower emissions
Polyisocyanurate (PIR) is a rigid thermoset foam with a thermal conductivity coefficient significantly lower than that of traditional insulation:
| Material | λD [W/(m·K)] | Thickness for U = 0.15 W/m²K |
|---|---|---|
| termPIR® MAX 19 AL | 0.019 | approx. 13 cm |
| termPIR® AL | 0.022 | approx. 15 cm |
| termPIR® ETX (glass fleece, ETICS) | 0.025–0.027 | 17–18 cm |
| Mineral wool façade | 0.036 | 24 cm |
| EPS 70 polystyrene | 0.040 | 27 cm |
A lower lambda means not only a thinner insulation layer, but above all lower real heat losses during operation — meaning less burnt fuel and less PM2.5 emitted to the atmosphere over the entire service life of the building.
Matching a PIR board to the envelope — key principles
Each envelope has its own functional requirements. Using the wrong facing leads to installation errors and loss of warranty.
- External wall in an ETICS system (thin-coat render) — requires a vapour-permeable facing. We use termPIR® ETX with glass fleece (ETA 17/0066). System: ETICS wall — termPIR® ETX.
- Pitched roof, over-rafter — eliminates thermal bridges in the timber structure and makes optimum use of the attic. Solution: pitched roof — over-rafter termPIR® with the termPIR® AL board.
- Flat roof on a reinforced concrete slab — gas-tight aluminium facing, compatible with heat-welded bituminous membrane. System: flat roof — reinforced concrete deck.
- Ground-bearing floor and foundation — enhanced moisture resistance: termPIR® WS.
- Internal insulation (e.g. heritage buildings where the façade cannot be altered) — a PIR + GK plasterboard composite with vapour barrier, selected individually.
Energy and emission outcomes of a thermal upgrade
In a typical single-family house from the 1980s–1990s, heat demand reaches 180–250 kWh/(m²·year). After a comprehensive thermal upgrade (roof + walls + windows + replacement of the heat source) this value drops to 50–80 kWh/(m²·year), and in the passive standard below 15 kWh/(m²·year). For a 150 m² building this means a reduction of fuel consumption by 2–4 tonnes of coal per year — and a corresponding reduction in PM2.5, PM10 and benzo(a)pyrene emissions released into the air in the neighbourhood.
On the scale of the Kraków metropolitan area, where according to Jagiellonian University research PM2.5 particulates trigger allergic reactions in three quarters of the population, every modernised boiler room and every properly insulated roof represents a measurable contribution to public health.
FAQ — frequently asked questions
Are PIR boards safe for health during use?
Yes. Once fully cured, rigid PIR foam is chemically inert, does not emit volatile substances under normal operating conditions and does not support mould growth. termPIR® boards with aluminium facing (AL/paper/PE) are additionally gas-tight, which stabilises λD over time. EN 13165 defines the requirements for PIR products used in construction, and the in-system fire reaction class is B-s2,d0.
What PIR thickness should I use on the roof to meet WT 2021?
For U ≤ 0.15 W/m²K with the termPIR® AL board (λD = 0.022) approximately 15 cm of insulation is sufficient; for termPIR® MAX 19 AL (λD = 0.019) — approximately 13 cm. The exact thickness depends on the remaining layers of the envelope (boarding, vapour barrier, air gaps). For thermal-upgrade projects we always recommend calculating U using the PN-EN ISO 6946 method.
Is termPIR® AL suitable for ETICS?
No. Boards with aluminium facing are gas-tight and do not work with thin-coat render (no adhesion of the bonding mortar, risk of blistering). For ETICS systems the dedicated product is termPIR® ETX with glass fleece and European Technical Assessment ETA 17/0066.
Does a thermal upgrade really reduce smog levels?
Yes — and directly so. Every kilowatt-hour of heat that doesn’t need to be produced is less fuel burnt in the boiler room. In buildings heated with coal or wood this means lower emissions of PM2.5, PM10, benzo(a)pyrene and sulphur oxides. Programmes such as “Czyste Powietrze” (Clean Air) combine thermal upgrades with replacement of the heat source for exactly this reason — the synergistic effect of both actions is the greatest.
What technical support does BOKKA offer in selecting insulation?
Our team will advise on the choice of board type (AL, ETX, MAX 19, WS) for a specific envelope, calculate the required thickness against WT 2021, indicate the fastening system and accessories (aluminium tapes, low-expansion foams, gaskets). We support single-family house projects, commercial buildings and industrial facilities — with delivery throughout Poland.
Planning a thermal upgrade? Browse the full range of termPIR® insulation boards or write via our contact form — we will prepare a quotation and technical selection tailored to your project.
