Ventilation and Air Conditioning Can Combat Poor Indoor Air Quality

The importance of indoor air quality cannot be underestimated. Public Health England (PHE) state that “Poor air quality is the largest environmental risk to public health in the UK, as long-term exposure to air pollution can cause chronic conditions such as cardiovascular and respiratory diseases as well as lung cancer, leading to reduced life expectancy.” In fact according to IQAir the 2024 UK PM2.5 air concentration was 1.5 times the World Health Organization annual PM2.5 guideline value.

A Royal College of Physicians (RCP) report says that “Indoor air also poses a growing concern, requiring considerably more attention. People spend the majority of their time in buildings, but there are few standards for pollutant concentrations in indoor air. Poor ventilation, damp and mould and emissions from domestic heating, gas cooking and cleaning products can all contribute to poor health.”

The concern of the RCP regarding the quality of indoor air is also voiced by Clean Air Day who found that nearly 50% of UK homes have high indoor air pollution. Research commissioned by Clean Air Day found that 71% of people said they feel their health is being affected by indoor air pollution. In another Clean Air Day study ultrafine particle pollution was found to be, “on average 3.5 times higher inside the home than outside - and in one case peaked at 560 times higher than outdoors.”

Chris Large, a senior partner at Global Action Plan, the charity behind Clean Air Day, said   “Indoor air pollution is a major issue that needs to be urgently addressed so this year the Clean Air Day campaign is putting the spotlight on air pollution indoors as well as outdoors.”

A Birmingham University article “Air pollution levels may be higher inside your home than outside” highlights research carried out to compare indoor to outdoor pollution levels in three homes using sensors and innovative techniques over a two-week period and found that “pollution levels in each house were higher and more variable than outdoor levels.” There were also significant differences in pollution levels between the three homes with one of the homes exceeding the World Health Organisation (WHO) 24-hour PM2.5 limit on nine days.

Airly, a global leader in air quality intelligence states that the air indoors often has 2-8 times higher levels of pollutants due to limited ventilation, than is found in outdoor air.

The World Economic Forum (WEF) emphasises the fact that when we discuss air pollution our first thought goes to outdoor pollution and the pollutants produced by vehicles and industry however we underestimate the pollution in the air we breathe indoors. They go onto say that “The stark reality is that many people, particularly vulnerable individuals, and children, are exposed to the highest concentrations of air pollutants indoors, in spaces typically considered safe. On average, people spend between 60–90% of their time indoors, while exposure to indoor air pollution is linked to an estimated 3.2 million premature deaths annually worldwide.”

Pollutants

Outdoor and indoor environments contain a variety of air pollutants. The sources of these pollutants differ between the two environments although there can be some crossover.

Outdoor

Outdoor pollutants consist of:

• Particulate Matter (PM₁₀ < 10 µm (e.g. dust, pollen), PM_2.5 < 2.5 µm (e.g. from vehicle exhausts, power plants, industrial emissions, wildfires, and burning wood) and PM_0.1 (ultrafine particles), tiny airborne particles from various sources including dust, dirt, soot, smoke, sea spray, and chemicals like sulphates, nitrates, and metals.
• Nitrogen Dioxide (NO₂), a toxic gas formed from burning fossil fuels (cars, power plants, boilers).
• Ozone (O₃), formed in the atmosphere from reactions between NOx and VOCs.
• Sulphur Dioxide (SO₂) from burning fossil fuels.
• Carbon Monoxide (CO) from the incomplete combustion of carbon-containing fuels.
• Benzene, 1,3-butadiene, and heavy metals (e.g. lead, cadmium, nickel and mercury, and the metalloid arsenic), toxic organic compounds and metals from industrial processes and vehicle emissions.
• Benzo[a]pyrene, a common, potent carcinogen found in smoke, coal tar, and grilled foods, formed from the incomplete burning of organic matter like wood, coal, and tobacco.
• Ammonia (NH₃), a corrosive, colourless gas from agriculture, composting, landfills, industrial processes, and vehicle exhausts with catalytic converters.
• Non-Methane Volatile Organic Compounds (VOCs), which come from both natural and anthropogenic sources including industrial processes and agriculture.

Indoor

Indoor pollutants consist of outdoor pollutants that enter buildings as well as indoor generated contaminants:

• CO, NO2 and PM from malfunctioning or unvented appliances such as boilers, heaters, fires, gas stoves, ovens or from tobacco smoke.
• Polycyclic Aromatic Hydrocarbons (PAHs), organic chemicals formed from the incomplete combustion of coal, oil, gas, wood, tobacco, cooking meat or burning candles.
• VOCs from building materials (e.g. carpets, upholstery, vinyl floors, new furniture), glues, paints, varnishes, cleaning products, air fresheners, personal care products, cosmetics, laundry detergents, laminate furniture, and office equipment.
• Benzene from smoking and some household products (e.g. paints and glue).
• Natural/biological pollutants such as Radon (Rn), a naturally occurring, colourless, odourless, radioactive gas formed from uranium decay in rocks and soil which seeps from the ground into buildings.
• Mould, mildew, dust mites, pet dander, bacteria, and viruses.
• Asbestos from older insulation, ceiling tiles, roof shingles, and floor tiles.
• Chemical pesticides that are used to kill or control pests indoors or which have been tracked in from the outside.
• Ozone from equipment like printers, portable air purifiers and from outdoors. 

Effect and Cost Of Air Pollutants On Health

Air pollution is the largest global environmental health risk causing millions of premature deaths every year. In the UK it’s estimated that long-term exposure to air pollution has “an annual effect equivalent to 28,000 to 36,000 deaths. PHE state that a 1ug/m³ reduction in fine particulate air pollution could prevent approximately 50,900 cases of coronary heart disease, 16,500 strokes, 9,300 cases of asthma and 4,200 lung cancers over an 18-year period.

According to the WHO almost every organ in the human body can be affected by air pollution as many pollutant’s small size means they can get into the bloodstream via the lungs and once in the bloodstream these pollutants can circulate throughout the body causing “systemic inflammation and carcinogenicity.”

Air pollution can have both short- and long-term health effects. In the short-term exposure to pollutants can lead to wheezing, coughing and asthma which in turn can impact lung function resulting in increased hospital admissions.

In the long-term exposure can cause stroke, ischaemic heart disease, chronic obstructive pulmonary disease, emphysema, lung cancer, chronic bronchitis, pneumonia, cataracts, dementia, and cognitive decline. There is evidence that air pollution exposure can cause low-birth weight, stillbirths, and developmental and neurological problems. Research also suggests that air pollution is linked to diabetes and other health problems.

As far back as 2010 the Environment Audit Committee estimated the cost of health impacts from poor air quality to be £8 to £20 billion. More recent analysis by the Royal College of Physicians (RCP) in 2025 suggests “an economic cost of £27 billion in the UK due to healthcare costs, productivity losses and reduced quality of life. When wider impacts such as dementia are accounted for, the economic cost may be as high as £50bn.”

PHE estimate that the potential cost to the NHS and social care systems in England alone between 2017 and 2025, due to the health impacts of PM_2.5 and NO₂ was £1.69 billion (£1.54 billion for PM_2.5 and £60.81 million for NO₂). The impact on the economy on productivity if people have to take time off work due to air pollution related illnesses was estimated by Department for Environment Food and Rural Affairs (DEFRA) to be £2.7 billion in 2012.

Ventilation and Air Conditioning

For residential and commercial buildings ensuring adequate ventilation is vital for health and wellbeing.

The UK government  state that it’s important to maximise the amount of fresh or purified air indoors through natural ventilation which comes from passive air flow through windows and doors or air vents and mechanical ventilation using fans and ducts including air conditioning to bring fresh air from the outside, inside.

A mechanical solution such as a Heating, Ventilation and Air Conditioning (HVAC) system, will give better overall control of ventilation and air quality. An HVAC system brings fresh air into a building thereby diluting the indoor pollutants and reduces the remaining air pollution by filtering the air taken in, removing dust, dirt, smoke, pollen, and other allergens.

A study on the Adverse Health Effects of Particulate Air Pollution showed that “communities with higher AC prevalence had lower particulate matter (PM) effects. Associations were observed for cardiovascular hospitalizations and central AC. Each additional 20% of households with central AC was associated with a 43% decrease in PM_2.5 effects on cardiovascular hospitalization. Central AC prevalence explained 17% of between-community variability in PM_2.5 effect estimates for cardiovascular hospitalizations.”

Bill Fisk, a senior scientist, and former leader of the Indoor Environment Group at Lawrence Berkeley National Laboratory explains: “AC can be expected to reduce the risk of heat stroke and heat-related death during heat waves, which are becoming more common with climate change. AC also enables windows to be maintained closed and AC systems usually contain filters that remove particles from the circulated air. With AC and closed windows, indoor concentrations of outdoor air pollutants such as particles, ozone and allergens are decreased.”

Cleveland Clinic’s Dr. Mark Aronica, an allergist-immunologist says: “For patients with allergies and other underlying respiratory diseases such as COPD/Emphysema, staying indoors with the air conditioning on and the windows closed, reduces exposure to outside pollens and pollutants.”

Clifford Bassett, MD, founder and medical director of Allergy and Asthma Care of New York and author of The New Allergy Solution states: “If you're someone who has indoor allergies, having A/C could actually help filter out some of the pollen, mould, and pollution that are in the air, which could make your symptoms more tolerable”.

Maintenance of HVAC Systems

In order to keep your HVAC working efficiently and effectively it’s vital to maintain it. Without maintenance your HVAC won’t do the job that it’s intended for. Where your HVAC is properly taken care of, serviced, filters are cleaned or replaced as required, the system is checked for leaks and tested your HVAC will continue to filter out particulates, dust and germs all year long, irrespective of the weather conditions outside.

Planned preventative maintenance also ensures you are F-Gas (a legal obligation for any business that operates an air conditioning system with a CO2 equivalent charge of 5 tonnes or more) and TM44 (an energy efficiency assessment of a buildings air conditioning system with a rated output of 12kW or more) compliant. Removing any uncertainty in the management of your system and giving you complete peace of mind.

Synecore – Experts In Heating, Ventilation and Air Conditioning

Synecore is an expert in HVAC design and installation in Kent, London, Surrey, Sussex, Essex. We are at the forefront of technological changes in the HVAC industry. We combine our technical expertise with the latest in HVAC technology to meet all your heating, ventilation, and air conditioning needs. Our design and fabrication service allows us to deliver sustainable HVAC design and installation solutions which match your floorplan, energy targets, and specific business needs.

We are an approved supplier and installation expert for air conditioning brands, Mitsubishi Electric, Toshiba, and Daikin. These brands are the disruptors in developing clean and efficient cooling and heating solutions for commercial and residential properties.

We also offer Planned Preventative Maintenance on commercial HVAC systems. New installations benefit from extended warranty periods when maintained by Synecore.

If you are looking to install a new air conditioning installation contact our team or call on 01795 509 509. We’ll talk you through your options and provide you with expert advice on the right system for you.