{"id":329,"date":"2026-08-21T04:01:28","date_gmt":"2026-08-21T04:01:28","guid":{"rendered":"https:\/\/www.deltafirst.co.uk\/blog\/workplace-air-quality\/"},"modified":"2026-10-03T16:55:49","modified_gmt":"2026-10-03T16:55:49","slug":"workplace-air-quality","status":"publish","type":"post","link":"https:\/\/www.deltafirst.co.uk\/blog\/workplace-air-quality\/","title":{"rendered":"Workplace air quality: what managers must do to comply"},"content":{"rendered":"<\/p>\n<p>If you manage a building, workplace air quality is not optional. Regulation 6 of the Workplace (Health, Safety and Welfare) Regulations 1992 requires you to ventilate every enclosed workspace with a sufficient supply of fresh or purified air, and COSHH adds a further duty wherever hazardous substances are airborne. In practice, this means four things right now: check ventilation is adequate, start CO2 logging, identify obvious pollutant sources, and document your planned preventative maintenance (PPM).<\/p>\n<p>Your first week should look like this:<\/p>\n<ul>\n<li>Walk the building and note damp patches, odours, blocked vents and inlet positions.<\/li>\n<li>Install a CO2 logger in your busiest occupied space and run it for at least a week.<\/li>\n<li>Check filters on air handling units (AHUs) and any local exhaust ventilation (LEV) for visible wear or damage.<\/li>\n<li>Book a PPM visit or commissioning check if none has happened in the last twelve months.<\/li>\n<\/ul>\n<p><strong>Statistic to know:<\/strong> the <a href=\"https:\/\/www.hse.gov.uk\/ventilation\/using-co2-monitors.htm\" rel=\"nofollow noopener noreferrer\" target=\"_blank\">HSE treats sustained occupied CO2 readings above 1500 ppm<\/a> as an indicator of poor ventilation, not a legal limit in itself, but a strong signal that action is overdue.<\/p>\n<h2 id=\"key-takeaways\" tabindex=\"-1\">Key Takeaways<\/h2>\n<p>Workplace air quality compliance depends on documented ventilation provision under Regulation 6, CO2 monitoring as a diagnostic tool, and COSHH controls wherever hazardous substances are present.<\/p>\n<table>\n<thead>\n<tr>\n<th>Point<\/th>\n<th>Details<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Regulation 6 sets the baseline duty<\/td>\n<td>Employers must provide sufficient fresh or purified air in every enclosed workplace, with fault warnings on plant where needed.<\/td>\n<\/tr>\n<tr>\n<td>CO2 is a diagnostic tool, not a limit<\/td>\n<td>Sustained readings above 1500 ppm signal poor ventilation and warrant investigation, not panic.<\/td>\n<\/tr>\n<tr>\n<td>COSHH governs hazardous substances<\/td>\n<td>Where airborne contaminants exceed Workplace Exposure Limits, exposure must be reduced ALARP.<\/td>\n<\/tr>\n<tr>\n<td>Scope before you test<\/td>\n<td>A walkthrough and desktop scoping study should precede any specialist monitoring to avoid unnecessary cost.<\/td>\n<\/tr>\n<tr>\n<td>Delta First delivers the fix<\/td>\n<td>Scoping surveys, PPM schedules, AHU servicing and LEV commissioning are available across Essex, Suffolk, Norfolk and Greater London.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2 id=\"table-of-contents\" tabindex=\"-1\">Table of Contents<\/h2>\n<ul>\n<li><a href=\"#why-workplace-air-quality-matters-for-health-productivity-and-business-risk\">Why workplace air quality matters for health, productivity and business risk<\/a><\/li>\n<li><a href=\"#what-are-your-legal-duties-under-regulation-6-and-coshh\">What are your legal duties under Regulation 6 and COSHH?<\/a><\/li>\n<li><a href=\"#what-are-the-common-pollutants-and-where-do-they-come-from\">What are the common pollutants and where do they come from?<\/a><\/li>\n<li><a href=\"#how-do-you-assess-indoor-air-quality-in-offices-and-industrial-buildings\">How do you assess indoor air quality in offices and industrial buildings?<\/a><\/li>\n<li><a href=\"#what-controls-actually-improve-workplace-ventilation-systems\">What controls actually improve workplace ventilation systems?<\/a><\/li>\n<li><a href=\"#how-should-ppm-schedules-and-maintenance-records-work\">How should PPM schedules and maintenance records work?<\/a><\/li>\n<li><a href=\"#when-should-you-call-in-a-specialist-for-testing-or-lev-work\">When should you call in a specialist for testing or LEV work?<\/a><\/li>\n<li><a href=\"#how-delta-first-helps-you-manage-workplace-air-quality\">How Delta First helps you manage workplace air quality<\/a><\/li>\n<li><a href=\"#frequently-asked-questions\">Frequently asked questions<\/a><\/li>\n<li><a href=\"#sources\">Sources<\/a><\/li>\n<\/ul>\n<h2 id=\"why-workplace-air-quality-matters-for-health-productivity-and-business-risk\" tabindex=\"-1\">Why workplace air quality matters for health, productivity and business risk<\/h2>\n<p>Poor ventilation costs money before it ever costs anything else. A review of the evidence on indoor air quality found that improvements in ventilation and filtration are frequently linked to measurable gains in productivity and reductions in absenteeism, with some interventions delivering returns several times their cost once staff performance and sick days are factored in.<\/p>\n<p>The health effects split into two tiers. Short-term exposure to stale or contaminated air brings headaches, eye and throat irritation, and a noticeable drop in concentration, the kind of thing staff mention in passing but rarely report formally. Long-term exposure to hazardous dusts, fumes or biological contaminants is a different matter entirely and can contribute to occupational lung disease, which is why COSHH exists alongside general ventilation duties.<\/p>\n<p>For a facilities manager building a case to the board, the argument is straightforward:<\/p>\n<ul>\n<li>Absence and reduced output from poor air quality typically dwarf the cost of a filter change or a duct clean.<\/li>\n<li>Thermal discomfort often gets blamed on \u201cstuffy air\u201d when the real fault is air distribution, so fixing one frequently resolves the other, a point echoed in the <a href=\"https:\/\/worldgbc.org\/wp-content\/uploads\/2022\/03\/WorldGBC-%E2%80%93-Health-Wellbeing-productivity-%E2%80%93-full-report-UK-single-low-res.pdf\" rel=\"nofollow noopener noreferrer\" target=\"_blank\">WorldGBC\u2019s review of health, wellbeing and productivity in offices<\/a>.<\/li>\n<li>A documented IAQ programme is cheaper to run than the reputational and legal cost of a preventable incident.<\/li>\n<\/ul>\n<h2 id=\"what-are-your-legal-duties-under-regulation-6-and-coshh\" tabindex=\"-1\">What are your legal duties under Regulation 6 and COSHH?<\/h2>\n<p>Regulation 6 is the backbone of your ventilation obligations. It requires you to make \u201ceffective and suitable provision\u201d so that every enclosed workplace receives a sufficient quantity of fresh or purified air, and where mechanical ventilation systems could fail silently, to fit a <a href=\"https:\/\/www.legislation.gov.uk\/uksi\/1992\/3004\/regulation\/6\/made\" rel=\"nofollow noopener noreferrer\" target=\"_blank\">visible or audible warning device<\/a> that alerts staff when plant stops working.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.deltafirst.co.uk\/blog\/wp-content\/uploads\/2026\/08\/1787061752536_Diagram-of-Regulation-6-ventilation-and-COSHH-compliance-steps.jpeg\" alt=\"Diagram of Regulation 6 ventilation and COSHH compliance steps\"><\/p>\n<p>COSHH sits on top of this general duty wherever specific hazardous substances are present, whether that is solvent vapours in a workshop, dust from grinding, or fumes from a process line. Where COSHH applies, exposure must stay within the Workplace Exposure Limits set out in EH40\/2005, and risk must be reduced as low as reasonably practicable (ALARP), not simply kept under the legal ceiling.<\/p>\n<p>Numbers help translate this into something you can actually check. HSE cites a benchmark of a few litres per second per person as suitable ventilation for most workplaces, and CO2 monitoring is the practical proxy most facilities teams use to check it is being achieved.<\/p>\n<blockquote>\n<p>A workplace with well-managed ventilation typically holds occupied CO2 readings around 700 to 750 ppm. Readings creeping toward 1150 to 1200 ppm suggest moderate ventilation pressure. Anything sustained above 1500 ppm is a signal to investigate, not ignore.<\/p>\n<\/blockquote>\n<p>Your compliance checklist should evidence all of the following:<\/p>\n<ul>\n<li>Current PPM logs for AHUs and extract systems, dated and signed.<\/li>\n<li>Commissioning or recommissioning reports for any ventilation plant installed or altered.<\/li>\n<li>LEV test certificates where process extraction is in use.<\/li>\n<li>A record of any occupant complaints and what action followed.<\/li>\n<\/ul>\n<h2 id=\"what-are-the-common-pollutants-and-where-do-they-come-from\" tabindex=\"-1\">What are the common pollutants and where do they come from?<\/h2>\n<p>Most workplace air quality problems trace back to a small set of repeat offenders. Knowing which one you are dealing with determines whether the fix is a filter change or a full COSHH assessment.<\/p>\n<ul>\n<li><strong>Particulates (PM2.5\/PM10)<\/strong>: traffic fumes drawn in through poorly sited inlets, construction dust, or process grinding and cutting.<\/li>\n<li><strong>Nitrogen dioxide (NO2)<\/strong>: combustion sources such as gas boilers, generators, and nearby road traffic.<\/li>\n<li><strong>Volatile organic compounds (VOCs)<\/strong>: cleaning products, adhesives, new furnishings, and paints, particularly in freshly refurbished spaces.<\/li>\n<li><strong>Carbon monoxide (CO)<\/strong>: faulty combustion appliances, poorly ventilated plant rooms, or vehicle exhaust ingress in car parks.<\/li>\n<li><strong>Biologicals and mould<\/strong>: damp building fabric, blocked drainage, and poorly maintained air handling units.<\/li>\n<li><strong>Radon<\/strong>: a geographic risk in certain regions, relevant mainly for ground-floor and basement spaces.<\/li>\n<\/ul>\n<p>VOCs, NO2, CO and process dusts are the substances most likely to trigger a COSHH assessment and WEL comparison. Mould, general staleness and thermal discomfort are usually managed through ventilation, humidity control and routine maintenance rather than exposure-limit testing.<\/p>\n<h2 id=\"how-do-you-assess-indoor-air-quality-in-offices-and-industrial-buildings\" tabindex=\"-1\">How do you assess indoor air quality in offices and industrial buildings?<\/h2>\n<p>A staged approach saves you money and stops you commissioning tests you do not need. The IAQM\u2019s guidance on indoor air quality assessment recommends scoping and walkthrough first, then targeted monitoring only for the contaminants your building is actually likely to have.<\/p>\n<ol>\n<li><strong>Scope the building.<\/strong> Note its location, activities, nearby external sources (busy roads, extraction flues, bin stores) and any vulnerable occupants, such as those with respiratory conditions.<\/li>\n<li><strong>Walk the site.<\/strong> Check for damp staining, odours, the position of external air inlets, the condition of AHUs, and whether LEV hoods and signage are present and intact. Ask staff where complaints tend to cluster.<\/li>\n<li><strong>Log CO2 over a full occupied period<\/strong>, not a single reading. Place the monitor away from doors, windows and individual desks, and let it run across a typical working week. Readings around 700 to 750 ppm indicate good ventilation; 1150 to 1200 ppm is moderate; sustained readings above 1500 ppm point to a ventilation shortfall that needs attention.<\/li>\n<li><strong>Commission targeted testing where indicated.<\/strong> VOC, NOx or particulate testing for suspected chemical or combustion sources; asbestos surveys for older building fabric being disturbed; radon testing in known risk areas.<\/li>\n<\/ol>\n<p>A single CO2 snapshot tells you very little; monitors are sensitive to placement and calibration drift, so trend data across occupied hours is what a competent assessor will rely on rather than one number pulled from a single afternoon.<\/p>\n<h2 id=\"what-controls-actually-improve-workplace-ventilation-systems\" tabindex=\"-1\">What controls actually improve workplace ventilation systems?<\/h2>\n<p>The hierarchy of controls that applies to most workplace hazards applies equally here. Eliminate the source first, then extract it, then dilute it, and only then rely on occupant behaviour.<\/p>\n<ul>\n<li><strong>Eliminate or substitute at source<\/strong>: swap high-VOC cleaning products, relocate combustion plant away from air inlets, or fix a leak causing damp before it becomes mould.<\/li>\n<li><strong>Local exhaust ventilation (LEV)<\/strong> for process contaminants such as welding fume, dust or solvent vapour. Properly designed and tested LEV, following HSE\u2019s HSG258 guidance, captures contamination at the point it is generated rather than diluting it into the general workspace.<\/li>\n<li><strong>Increase fresh air supply<\/strong>, whether through natural ventilation (openable windows, trickle vents) or mechanical systems, matched to occupancy density.<\/li>\n<li><strong>Improve filtration<\/strong> on AHUs and portable units, particularly where the external environment is polluted enough that opening windows makes things worse rather than better.<\/li>\n<li><strong>Control humidity and damp<\/strong> to prevent mould growth, which is often a maintenance failure rather than a design one.<\/li>\n<\/ul>\n<p>Natural ventilation works well for low-occupancy, well-sited buildings, but it struggles near busy roads or in extreme weather, when mechanical or mixed-mode ventilation becomes the more reliable option. On filtration, a coarse pre-filter protects a finer secondary filter from clogging prematurely; the sensible approach for most commercial AHUs is scheduled replacement based on differential pressure readings rather than a fixed calendar date, particularly in buildings near heavy traffic.<\/p>\n<p><strong>Pro Tip:<\/strong> <em>Check where your fresh air inlet actually sits before you spend money on filtration. An inlet positioned above a bin store, next to a car park exit, or downwind of a kitchen extract will undermine even the best filter, and it is often a five-minute fix once spotted.<\/em><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.deltafirst.co.uk\/blog\/wp-content\/uploads\/2026\/08\/1787061707769_Fresh-air-inlet-grille-near-car-park-exit.jpeg\" alt=\"Fresh air inlet grille near car park exit\"><\/p>\n<h2 id=\"how-should-ppm-schedules-and-maintenance-records-work\" tabindex=\"-1\">How should PPM schedules and maintenance records work?<\/h2>\n<p>Ventilation systems fail quietly. A fan belt slips, a filter clogs, or a sensor drifts out of calibration, and nobody notices until CO2 levels or complaint numbers climb. A documented PPM schedule is what catches this before it becomes a compliance problem.<\/p>\n<p>Your schedule should cover:<\/p>\n<ul>\n<li>Routine AHU servicing, filter inspection and replacement on a fixed interval or pressure-triggered basis.<\/li>\n<li>Duct cleaning where buildup is likely, particularly in kitchens or dusty processes.<\/li>\n<li>LEV testing at the frequency set out in your commissioning documentation, typically annually.<\/li>\n<li>Logbook entries recorded at every visit, not just when something goes wrong.<\/li>\n<\/ul>\n<p>Keep the following on file: commissioning sheets for any new or altered plant, maintenance logs going back at least two years, exported CO2 trend data, incident or complaint reports, and a record of staff consultation on air quality concerns. Where plant failure would not be immediately obvious, Regulation 6 expects a visible or audible warning device to flag it automatically, with a clear route for that fault to reach your maintenance contractor.<\/p>\n<p>A workable PPM plan for AHUs and ventilation plant sets out exactly this kind of recurring schedule, and it is worth reviewing alongside seasonal guidance such as a summer HVAC maintenance checklist, since ventilation demand and filter loading both shift with the seasons.<\/p>\n<h2 id=\"when-should-you-call-in-a-specialist-for-testing-or-lev-work\" tabindex=\"-1\">When should you call in a specialist for testing or LEV work?<\/h2>\n<p>Some situations sit beyond what an in-house walkthrough can safely resolve. Bring in a specialist when you see any of the following:<\/p>\n<ul>\n<li>CO2 readings sustained above 1500 ppm despite basic ventilation adjustments.<\/li>\n<li>Unexplained clusters of headaches, fatigue or respiratory complaints among staff.<\/li>\n<li>Suspected hazardous dusts, fumes or solvent vapours that may trigger COSHH.<\/li>\n<li>A process that needs new or reconfigured LEV, or an existing system that has never been tested.<\/li>\n<li>Suspected radon in a ground-floor or basement space.<\/li>\n<\/ul>\n<p>A competent contractor should hold demonstrable COSHH and LEV experience and should hand you a scoping report, monitoring data, and where relevant a LEV design and commissioning certificate. The output that matters most is a prioritised list of remediation actions you can act on immediately, not just a stack of raw data.<\/p>\n<h3 id=\"a-pragmatic-view-from-a-building-services-contractor\" tabindex=\"-1\">A pragmatic view from a building services contractor<\/h3>\n<p>The most common mistake we see is treating air quality as a one-off test rather than an ongoing PPM commitment. Fixing an inlet position or replacing a filter costs little; the expensive failures happen when nobody was logging CO2 or servicing the AHU in the first place. Documented maintenance, not perfect air, is usually what protects you.<\/p>\n<h2 id=\"how-delta-first-helps-you-manage-workplace-air-quality\" tabindex=\"-1\">How Delta First helps you manage workplace air quality<\/h2>\n<p>Delta First is a direct route to compliant ventilation, not another layer of consultancy sitting between you and the engineers who actually do the work. Our directly employed engineers deliver PPM, AHU servicing, LEV design and commissioning, filtration upgrades and reactive callouts across Essex, Suffolk, Norfolk and Greater London, so the same team that surveys your building is the one that fixes it.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.deltafirst.co.uk\/blog\/wp-content\/uploads\/2026\/07\/1783116648075_deltafirst.jpg\" alt=\"Delta First\"><\/p>\n<p>Commission a scoping survey with us and you get a written report ranking your priorities, not a generic checklist. That report feeds directly into a recommended PPM schedule tailored to your building\u2019s occupancy, plant age and pollutant risks. Whether you are managing a school, an office block or an industrial unit, our <a href=\"https:\/\/deltafirst.co.uk\/sectors\/commercial-offices.html\" target=\"_blank\" rel=\"noopener\">commercial office building services<\/a> team can walk you through what a scoping visit involves and what it costs. If terms like AHU, LEV or WEL are new to your team, our <a href=\"https:\/\/deltafirst.co.uk\/glossary\" target=\"_blank\" rel=\"noopener\">building services glossary<\/a> is a useful reference to share with non-technical colleagues before that first conversation. Get in touch to request a quotation or book a planned maintenance survey.<\/p>\n<h2 id=\"frequently-asked-questions\" tabindex=\"-1\">Frequently asked questions<\/h2>\n<p><strong>What CO2 level indicates poor ventilation in an office?<\/strong><br \/>\nSustained occupied readings above 1500 ppm are treated by HSE as an indicator of poor ventilation. Readings around 700 to 750 ppm suggest good ventilation, while 1150 to 1200 ppm sits in a moderate range worth monitoring.<\/p>\n<p><strong>Is CO2 monitoring a legal requirement under Regulation 6?<\/strong><br \/>\nNo single statutory CO2 limit exists. Regulation 6 requires \u201csufficient\u201d fresh or purified air, and CO2 monitoring is the practical tool most facilities teams use to demonstrate that duty is being met.<\/p>\n<p><strong>When does COSHH apply to workplace air quality?<\/strong><br \/>\nCOSHH applies wherever specific hazardous substances, such as solvent vapours, process dusts or fumes, are present in the air. General staleness or thermal discomfort without a hazardous substance present is managed through ventilation duties rather than COSHH.<\/p>\n<p><strong>How often should AHUs and LEV systems be tested?<\/strong><br \/>\nLEV systems are typically tested annually under HSG258 guidance, though frequency depends on the process and risk. AHU servicing intervals vary with filter loading and occupancy, which is why a documented PPM schedule matters more than a fixed calendar rule.<\/p>\n<p><strong>Can Delta First carry out a workplace air quality survey?<\/strong><br \/>\nYes. Delta First\u2019s directly employed engineers can carry out a scoping survey, recommend a PPM schedule, and deliver AHU servicing, filtration upgrades and LEV commissioning across Essex, Suffolk, Norfolk and Greater London.<\/p>\n<p>This article is general information, not a substitute for advice from a qualified lawyer. Consult a qualified legal professional about your own circumstances before acting on anything here.<\/p>\n<h2 id=\"sources\" tabindex=\"-1\">Sources<\/h2>\n<p>For legal citation, go straight to the Workplace (Health, Safety and Welfare) Regulations 1992, Regulation 6. For exposure limits on hazardous substances, use EH40\/2005. For staged assessment methodology, the IAQM guidance document is the clearest reference. For LEV design, testing and maintenance, consult HSG258. For the productivity and financial case behind IAQ investment, the ERAU review of IAQ evidence sets out the research base. For practical HVAC maintenance scheduling, this preventive maintenance schedule guide offers a complementary industry perspective.<\/p>\n<ul>\n<li><a href=\"https:\/\/www.hse.gov.uk\/ventilation\/using-co2-monitors.htm\" rel=\"nofollow noopener noreferrer\" target=\"_blank\">Using CO2 monitors to assess ventilation<\/a><\/li>\n<li><a href=\"https:\/\/www.legislation.gov.uk\/uksi\/1992\/3004\/regulation\/6\/made\" rel=\"nofollow noopener noreferrer\" target=\"_blank\">The Workplace (Health, Safety and Welfare) Regulations 1992: regulation 6<\/a><\/li>\n<li>The value of IAQ: review of scientific evidence supporting benefits of better indoor air quality<\/li>\n<\/ul>\n<h2 id=\"recommended\" tabindex=\"-1\">Recommended<\/h2>\n<ul>\n<li><a href=\"https:\/\/deltafirst.co.uk\/blog\/summer-hvac-maintenance\" target=\"_blank\" rel=\"noopener\">Summer HVAC maintenance: a guide for facilities managers<\/a><\/li>\n<li><a href=\"https:\/\/deltafirst.co.uk\/blog\/air-conditioning-consulting\" target=\"_blank\" rel=\"noopener\">Air conditioning consulting for facilities managers: UK guide<\/a><\/li>\n<li><a href=\"https:\/\/deltafirst.co.uk\/blog\/esos-uk\" target=\"_blank\" rel=\"noopener\">ESOS UK: the 2026 compliance guide for large organisations<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Ensure compliance with workplace air quality regulations. Discover essential steps to improve ventilation, monitor CO2, and maintain a healthy environment.<\/p>\n","protected":false},"author":2,"featured_media":330,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","footnotes":""},"categories":[7,13],"tags":[786,792,55,121,339,794,800,310,37,117,797,801,799,57,795,803,583,787,791,784,802,693,796,125,61,793,141,782,788,783,515,798,785,789,790],"class_list":["post-329","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-compliance","category-facilities-management","tag-air-quality-compliance","tag-air-quality-monitoring","tag-building-services","tag-commercial-building-maintenance","tag-commercial-buildings","tag-commercial-ventilation","tag-coshh","tag-delta-first-building-services","tag-facilities-management","tag-facilities-managers","tag-fresh-air-ventilation","tag-healthy-buildings","tag-hse-compliance","tag-hvac-maintenance","tag-hvac-ventilation","tag-iaq","tag-indoor-air-quality","tag-indoor-air-quality-regulations","tag-indoor-air-quality-testing","tag-indoor-air-quality-uk","tag-indoor-environmental-quality","tag-mechanical-building-services","tag-mechanical-ventilation","tag-statutory-compliance","tag-uk-facilities-management","tag-ventilation-compliance","tag-ventilation-maintenance","tag-workplace-air-quality","tag-workplace-air-quality-regulations","tag-workplace-air-quality-uk","tag-workplace-compliance","tag-workplace-health-and-safety","tag-workplace-indoor-air-quality","tag-workplace-ventilation","tag-workplace-ventilation-requirements"],"blocksy_meta":[],"uagb_featured_image_src":{"full":["https:\/\/www.deltafirst.co.uk\/blog\/wp-content\/uploads\/2026\/08\/1787061698535_Hands-adjusting-air-quality-sensor-indoors.jpeg",1080,720,false],"thumbnail":["https:\/\/www.deltafirst.co.uk\/blog\/wp-content\/uploads\/2026\/08\/1787061698535_Hands-adjusting-air-quality-sensor-indoors-150x150.jpeg",150,150,true],"medium":["https:\/\/www.deltafirst.co.uk\/blog\/wp-content\/uploads\/2026\/08\/1787061698535_Hands-adjusting-air-quality-sensor-indoors-300x200.jpeg",300,200,true],"medium_large":["https:\/\/www.deltafirst.co.uk\/blog\/wp-content\/uploads\/2026\/08\/1787061698535_Hands-adjusting-air-quality-sensor-indoors-768x512.jpeg",768,512,true],"large":["https:\/\/www.deltafirst.co.uk\/blog\/wp-content\/uploads\/2026\/08\/1787061698535_Hands-adjusting-air-quality-sensor-indoors-1024x683.jpeg",1024,683,true],"1536x1536":["https:\/\/www.deltafirst.co.uk\/blog\/wp-content\/uploads\/2026\/08\/1787061698535_Hands-adjusting-air-quality-sensor-indoors.jpeg",1080,720,false],"2048x2048":["https:\/\/www.deltafirst.co.uk\/blog\/wp-content\/uploads\/2026\/08\/1787061698535_Hands-adjusting-air-quality-sensor-indoors.jpeg",1080,720,false]},"uagb_author_info":{"display_name":"Delta First Editorial Team","author_link":"https:\/\/www.deltafirst.co.uk\/blog\/author\/deltaeditor\/"},"uagb_comment_info":0,"uagb_excerpt":"Ensure compliance with workplace air quality regulations. 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